mcp-types (empty) → 0.1.0

raw patch · 7 files changed

+3439/−0 lines, 7 filesdep +aesondep +basedep +containers

Dependencies added: aeson, base, containers, hspec, jsonrpc, mcp-types, text

Files

• CHANGELOG.md +16/−0
• LICENSE +373/−0
• mcp-types.cabal +96/−0
• src/MCP/Aeson.hs +27/−0
• src/MCP/Protocol.hs +1303/−0
• src/MCP/Types.hs +1130/−0
• test/Main.hs +494/−0

@@ -0,0 +1,16 @@+# Changelog++## 0.1.0++### Added+- Initial release, split from the `mcp` package.+- `MCP.Types`: Core MCP data types (Content, Resource, Tool, Prompt, Capability, etc.)+- `MCP.Protocol`: JSON-RPC 2.0 message wrappers and all client/server request/response types.+- `MCP.Aeson`: Custom Aeson parsing options.++### Fixed+- Make `params` optional in `JSONRPCRequest`, `JSONRPCNotification`,+  `ViaJSONRPCRequest`, and `ViaJSONRPCNotification` `FromJSON` instances.+  JSON-RPC 2.0 allows omitting the `params` field; previously a missing+  `params` caused requests to be silently misparsed as notifications+  (losing the `id` and never receiving a response).

@@ -0,0 +1,373 @@+Mozilla Public License Version 2.0+==================================++1. Definitions+--------------++1.1. "Contributor"+    means each individual or legal entity that creates, contributes to+    the creation of, or owns Covered Software.++1.2. "Contributor Version"+    means the combination of the Contributions of others (if any) used+    by a Contributor and that particular Contributor's Contribution.++1.3. "Contribution"+    means Covered Software of a particular Contributor.++1.4. "Covered Software"+    means Source Code Form to which the initial Contributor has attached+    the notice in Exhibit A, the Executable Form of such Source Code+    Form, and Modifications of such Source Code Form, in each case+    including portions thereof.++1.5. "Incompatible With Secondary Licenses"+    means++    (a) that the initial Contributor has attached the notice described+        in Exhibit B to the Covered Software; or++    (b) that the Covered Software was made available under the terms of+        version 1.1 or earlier of the License, but not also under the+        terms of a Secondary License.++1.6. "Executable Form"+    means any form of the work other than Source Code Form.++1.7. "Larger Work"+    means a work that combines Covered Software with other material, in+    a separate file or files, that is not Covered Software.++1.8. "License"+    means this document.++1.9. "Licensable"+    means having the right to grant, to the maximum extent possible,+    whether at the time of the initial grant or subsequently, any and+    all of the rights conveyed by this License.++1.10. "Modifications"+    means any of the following:++    (a) any file in Source Code Form that results from an addition to,+        deletion from, or modification of the contents of Covered+        Software; or++    (b) any new file in Source Code Form that contains any Covered+        Software.++1.11. "Patent Claims" of a Contributor+    means any patent claim(s), including without limitation, method,+    process, and apparatus claims, in any patent Licensable by such+    Contributor that would be infringed, but for the grant of the+    License, by the making, using, selling, offering for sale, having+    made, import, or transfer of either its Contributions or its+    Contributor Version.++1.12. "Secondary License"+    means either the GNU General Public License, Version 2.0, the GNU+    Lesser General Public License, Version 2.1, the GNU Affero General+    Public License, Version 3.0, or any later versions of those+    licenses.++1.13. "Source Code Form"+    means the form of the work preferred for making modifications.++1.14. "You" (or "Your")+    means an individual or a legal entity exercising rights under this+    License. For legal entities, "You" includes any entity that+    controls, is controlled by, or is under common control with You. For+    purposes of this definition, "control" means (a) the power, direct+    or indirect, to cause the direction or management of such entity,+    whether by contract or otherwise, or (b) ownership of more than+    fifty percent (50%) of the outstanding shares or beneficial+    ownership of such entity.++2. License Grants and Conditions+--------------------------------++2.1. Grants++Each Contributor hereby grants You a world-wide, royalty-free,+non-exclusive license:++(a) under intellectual property rights (other than patent or trademark)+    Licensable by such Contributor to use, reproduce, make available,+    modify, display, perform, distribute, and otherwise exploit its+    Contributions, either on an unmodified basis, with Modifications, or+    as part of a Larger Work; and++(b) under Patent Claims of such Contributor to make, use, sell, offer+    for sale, have made, import, and otherwise transfer either its+    Contributions or its Contributor Version.++2.2. Effective Date++The licenses granted in Section 2.1 with respect to any Contribution+become effective for each Contribution on the date the Contributor first+distributes such Contribution.++2.3. Limitations on Grant Scope++The licenses granted in this Section 2 are the only rights granted under+this License. No additional rights or licenses will be implied from the+distribution or licensing of Covered Software under this License.+Notwithstanding Section 2.1(b) above, no patent license is granted by a+Contributor:++(a) for any code that a Contributor has removed from Covered Software;+    or++(b) for infringements caused by: (i) Your and any other third party's+    modifications of Covered Software, or (ii) the combination of its+    Contributions with other software (except as part of its Contributor+    Version); or++(c) under Patent Claims infringed by Covered Software in the absence of+    its Contributions.++This License does not grant any rights in the trademarks, service marks,+or logos of any Contributor (except as may be necessary to comply with+the notice requirements in Section 3.4).++2.4. Subsequent Licenses++No Contributor makes additional grants as a result of Your choice to+distribute the Covered Software under a subsequent version of this+License (see Section 10.2) or under the terms of a Secondary License (if+permitted under the terms of Section 3.3).++2.5. Representation++Each Contributor represents that the Contributor believes its+Contributions are its original creation(s) or it has sufficient rights+to grant the rights to its Contributions conveyed by this License.++2.6. Fair Use++This License is not intended to limit any rights You have under+applicable copyright doctrines of fair use, fair dealing, or other+equivalents.++2.7. Conditions++Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted+in Section 2.1.++3. Responsibilities+-------------------++3.1. Distribution of Source Form++All distribution of Covered Software in Source Code Form, including any+Modifications that You create or to which You contribute, must be under+the terms of this License. You must inform recipients that the Source+Code Form of the Covered Software is governed by the terms of this+License, and how they can obtain a copy of this License. You may not+attempt to alter or restrict the recipients' rights in the Source Code+Form.++3.2. Distribution of Executable Form++If You distribute Covered Software in Executable Form then:++(a) such Covered Software must also be made available in Source Code+    Form, as described in Section 3.1, and You must inform recipients of+    the Executable Form how they can obtain a copy of such Source Code+    Form by reasonable means in a timely manner, at a charge no more+    than the cost of distribution to the recipient; and++(b) You may distribute such Executable Form under the terms of this+    License, or sublicense it under different terms, provided that the+    license for the Executable Form does not attempt to limit or alter+    the recipients' rights in the Source Code Form under this License.++3.3. Distribution of a Larger Work++You may create and distribute a Larger Work under terms of Your choice,+provided that You also comply with the requirements of this License for+the Covered Software. If the Larger Work is a combination of Covered+Software with a work governed by one or more Secondary Licenses, and the+Covered Software is not Incompatible With Secondary Licenses, this+License permits You to additionally distribute such Covered Software+under the terms of such Secondary License(s), so that the recipient of+the Larger Work may, at their option, further distribute the Covered+Software under the terms of either this License or such Secondary+License(s).++3.4. Notices++You may not remove or alter the substance of any license notices+(including copyright notices, patent notices, disclaimers of warranty,+or limitations of liability) contained within the Source Code Form of+the Covered Software, except that You may alter any license notices to+the extent required to remedy known factual inaccuracies.++3.5. Application of Additional Terms++You may choose to offer, and to charge a fee for, warranty, support,+indemnity or liability obligations to one or more recipients of Covered+Software. However, You may do so only on Your own behalf, and not on+behalf of any Contributor. You must make it absolutely clear that any+such warranty, support, indemnity, or liability obligation is offered by+You alone, and You hereby agree to indemnify every Contributor for any+liability incurred by such Contributor as a result of warranty, support,+indemnity or liability terms You offer. You may include additional+disclaimers of warranty and limitations of liability specific to any+jurisdiction.++4. Inability to Comply Due to Statute or Regulation+---------------------------------------------------++If it is impossible for You to comply with any of the terms of this+License with respect to some or all of the Covered Software due to+statute, judicial order, or regulation then You must: (a) comply with+the terms of this License to the maximum extent possible; and (b)+describe the limitations and the code they affect. Such description must+be placed in a text file included with all distributions of the Covered+Software under this License. Except to the extent prohibited by statute+or regulation, such description must be sufficiently detailed for a+recipient of ordinary skill to be able to understand it.++5. Termination+--------------++5.1. The rights granted under this License will terminate automatically+if You fail to comply with any of its terms. However, if You become+compliant, then the rights granted under this License from a particular+Contributor are reinstated (a) provisionally, unless and until such+Contributor explicitly and finally terminates Your grants, and (b) on an+ongoing basis, if such Contributor fails to notify You of the+non-compliance by some reasonable means prior to 60 days after You have+come back into compliance. Moreover, Your grants from a particular+Contributor are reinstated on an ongoing basis if such Contributor+notifies You of the non-compliance by some reasonable means, this is the+first time You have received notice of non-compliance with this License+from such Contributor, and You become compliant prior to 30 days after+Your receipt of the notice.++5.2. If You initiate litigation against any entity by asserting a patent+infringement claim (excluding declaratory judgment actions,+counter-claims, and cross-claims) alleging that a Contributor Version+directly or indirectly infringes any patent, then the rights granted to+You by any and all Contributors for the Covered Software under Section+2.1 of this License shall terminate.++5.3. In the event of termination under Sections 5.1 or 5.2 above, all+end user license agreements (excluding distributors and resellers) which+have been validly granted by You or Your distributors under this License+prior to termination shall survive termination.++************************************************************************+*                                                                      *+*  6. Disclaimer of Warranty                                           *+*  -------------------------                                           *+*                                                                      *+*  Covered Software is provided under this License on an "as is"       *+*  basis, without warranty of any kind, either expressed, implied, or  *+*  statutory, including, without limitation, warranties that the       *+*  Covered Software is free of defects, merchantable, fit for a        *+*  particular purpose or non-infringing. The entire risk as to the     *+*  quality and performance of the Covered Software is with You.        *+*  Should any Covered Software prove defective in any respect, You     *+*  (not any Contributor) assume the cost of any necessary servicing,   *+*  repair, or correction. This disclaimer of warranty constitutes an   *+*  essential part of this License. No use of any Covered Software is   *+*  authorized under this License except under this disclaimer.         *+*                                                                      *+************************************************************************++************************************************************************+*                                                                      *+*  7. Limitation of Liability                                          *+*  --------------------------                                          *+*                                                                      *+*  Under no circumstances and under no legal theory, whether tort      *+*  (including negligence), contract, or otherwise, shall any           *+*  Contributor, or anyone who distributes Covered Software as          *+*  permitted above, be liable to You for any direct, indirect,         *+*  special, incidental, or consequential damages of any character      *+*  including, without limitation, damages for lost profits, loss of    *+*  goodwill, work stoppage, computer failure or malfunction, or any    *+*  and all other commercial damages or losses, even if such party      *+*  shall have been informed of the possibility of such damages. This   *+*  limitation of liability shall not apply to liability for death or   *+*  personal injury resulting from such party's negligence to the       *+*  extent applicable law prohibits such limitation. Some               *+*  jurisdictions do not allow the exclusion or limitation of           *+*  incidental or consequential damages, so this exclusion and          *+*  limitation may not apply to You.                                    *+*                                                                      *+************************************************************************++8. Litigation+-------------++Any litigation relating to this License may be brought only in the+courts of a jurisdiction where the defendant maintains its principal+place of business and such litigation shall be governed by laws of that+jurisdiction, without reference to its conflict-of-law provisions.+Nothing in this Section shall prevent a party's ability to bring+cross-claims or counter-claims.++9. Miscellaneous+----------------++This License represents the complete agreement concerning the subject+matter hereof. If any provision of this License is held to be+unenforceable, such provision shall be reformed only to the extent+necessary to make it enforceable. Any law or regulation which provides+that the language of a contract shall be construed against the drafter+shall not be used to construe this License against a Contributor.++10. Versions of the License+---------------------------++10.1. New Versions++Mozilla Foundation is the license steward. Except as provided in Section+10.3, no one other than the license steward has the right to modify or+publish new versions of this License. Each version will be given a+distinguishing version number.++10.2. Effect of New Versions++You may distribute the Covered Software under the terms of the version+of the License under which You originally received the Covered Software,+or under the terms of any subsequent version published by the license+steward.++10.3. Modified Versions++If you create software not governed by this License, and you want to+create a new license for such software, you may create and use a+modified version of this License if you rename the license and remove+any references to the name of the license steward (except to note that+such modified license differs from this License).++10.4. Distributing Source Code Form that is Incompatible With Secondary+Licenses++If You choose to distribute Source Code Form that is Incompatible With+Secondary Licenses under the terms of this version of the License, the+notice described in Exhibit B of this License must be attached.++Exhibit A - Source Code Form License Notice+-------------------------------------------++  This Source Code Form is subject to the terms of the Mozilla Public+  License, v. 2.0. If a copy of the MPL was not distributed with this+  file, You can obtain one at https://mozilla.org/MPL/2.0/.++If it is not possible or desirable to put the notice in a particular+file, then You may include the notice in a location (such as a LICENSE+file in a relevant directory) where a recipient would be likely to look+for such a notice.++You may add additional accurate notices of copyright ownership.++Exhibit B - "Incompatible With Secondary Licenses" Notice+---------------------------------------------------------++  This Source Code Form is "Incompatible With Secondary Licenses", as+  defined by the Mozilla Public License, v. 2.0.

@@ -0,0 +1,96 @@+cabal-version: 2.2+name: mcp-types+version: 0.1.0+license: MPL-2.0+license-file: LICENSE+copyright: (c) 2025 DPella AB+author: DPella AB+tested-with: ghc ==9.12.2+extra-doc-files:+  CHANGELOG.md++maintainer:+  matti@dpella.io,+  lobo@dpella.io++synopsis: Core types and protocol definitions for the Model Context Protocol (MCP)+description:+  This library provides the core type definitions and JSON-RPC protocol layer+  for the Model Context Protocol (MCP). MCP is a protocol that enables seamless+  communication between AI models and external tools, resources, and services.+  .+  This package contains only the pure protocol types with minimal dependencies,+  making it suitable for building both clients and servers on any framework.+  For a ready-made Servant-based server, see the @mcp@ package.++homepage: https://github.com/DPella/mcp+bug-reports: https://github.com/DPella/mcp/issues+category: Web, AI++source-repository head+  type: git+  location: https://github.com/DPella/mcp.git++library+  default-language:+    Haskell2010++  default-extensions:+    DataKinds+    FlexibleInstances+    GADTs+    GeneralizedNewtypeDeriving+    ImportQualifiedPost+    LambdaCase+    OverloadedStrings+    PolyKinds+    RankNTypes+    TypeApplications+    TypeFamilies++  hs-source-dirs:+    src++  exposed-modules:+    MCP.Aeson+    MCP.Protocol+    MCP.Types++  build-depends:+    aeson >=2.1 && <2.3,+    base >=4.18 && <4.22,+    containers >=0.6 && <0.8,+    jsonrpc >=0.2.0 && <0.3,+    text >=2.0 && <2.2,++test-suite test-mcp-types+  type: exitcode-stdio-1.0+  default-language:+    Haskell2010++  default-extensions:+    DataKinds+    FlexibleInstances+    GADTs+    GeneralizedNewtypeDeriving+    ImportQualifiedPost+    LambdaCase+    OverloadedStrings+    PolyKinds+    RankNTypes+    TypeApplications+    TypeFamilies++  hs-source-dirs:+    test++  main-is:+    Main.hs++  build-depends:+    aeson >=2.1 && <2.3,+    base >=4.18 && <4.22,+    containers >=0.6 && <0.8,+    hspec >=2.10 && <2.12,+    jsonrpc >=0.2.0 && <0.3,+    mcp-types,

@@ -0,0 +1,27 @@+{- |+Module:      MCP.Aeson+Copyright:   (c) DPella AB 2025+License:     MPL-2.0+Maintainer:  <matti@dpella.io>, <lobo@dpella.io>+-}+module MCP.Aeson where++import Data.Aeson+import Data.List (stripPrefix)++-- | Custom Aeson parsing options for MCP types.+mcpParseOpts :: Options+mcpParseOpts =+    defaultOptions+        { omitNothingFields = True+        , fieldLabelModifier = flm+        }+  where+    -- Custom field label modifier to handle "_meta" field+    flm :: String -> String+    flm "_meta" = "_meta"+    -- Handle duplicate record fields+    flm fl+        | Just with_sel <- stripPrefix "$sel:" fl =+            takeWhile (/= ':') with_sel+    flm fl = fl

@@ -0,0 +1,1303 @@+{-# HLINT ignore "Use newtype instead of data" #-}+{-# LANGUAGE DeriveAnyClass #-}+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE DerivingVia #-}+{-# LANGUAGE DuplicateRecordFields #-}+{-# LANGUAGE LambdaCase #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TemplateHaskell #-}+{-# LANGUAGE TypeFamilies #-}+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}++{- |+Module      : MCP.Protocol+Description : MCP protocol types built on JSON-RPC 2.0+Copyright   : (C) 2025 DPella AB+License     : MPL-2.0+Maintainer  : matti@dpella.io, lobo@dpella.io+Stability   : experimental+Portability : GHC++This module defines the Model Context Protocol (MCP) request, response,+and notification types.  The underlying JSON-RPC 2.0 transport types are+re-exported from the @jsonrpc@ package.+-}+module MCP.Protocol (+    -- * JSON-RPC types (re-exported from "JSONRPC")+    module JSONRPC,++    -- * Client Request Types+    InitializeRequest (..),+    InitializeParams (..),+    PingRequest (..),+    PingParams (..),+    ListResourcesRequest (..),+    ListResourcesParams (..),+    ListResourceTemplatesRequest (..),+    ListResourceTemplatesParams (..),+    ReadResourceRequest (..),+    ReadResourceParams (..),+    SubscribeRequest (..),+    SubscribeParams (..),+    UnsubscribeRequest (..),+    UnsubscribeParams (..),+    ListPromptsRequest (..),+    ListPromptsParams (..),+    GetPromptRequest (..),+    GetPromptParams (..),+    ListToolsRequest (..),+    ListToolsParams (..),+    CallToolRequest (..),+    CallToolParams (..),+    SetLevelRequest (..),+    SetLevelParams (..),+    CompleteRequest (..),+    CompleteParams (..),+    CompletionContext (..),+    CompletionArgument (..),+    Reference (..),++    -- * Server Request Types+    CreateMessageRequest (..),+    CreateMessageParams (..),+    ListRootsRequest (..),+    ListRootsParams (..),+    ElicitRequest (..),+    ElicitParams (..),+    PrimitiveSchemaDefinition (..),++    -- * Response Types+    InitializeResult (..),+    ListResourcesResult (..),+    ListResourceTemplatesResult (..),+    ReadResourceResult (..),+    ListPromptsResult (..),+    GetPromptResult (..),+    ListToolsResult (..),+    CallToolResult (..),+    CompleteResult (..),+    CompletionResult (..),+    CreateMessageResult (..),+    ListRootsResult (..),+    ElicitResult (..),++    -- * Notification Types+    CancelledNotification (..),+    CancelledParams (..),+    InitializedNotification (..),+    InitializedParams (..),+    ProgressNotification (..),+    ProgressParams (..),+    ResourceListChangedNotification (..),+    ResourceUpdatedNotification (..),+    ResourceUpdatedParams (..),+    PromptListChangedNotification (..),+    ToolListChangedNotification (..),+    LoggingMessageNotification (..),+    LoggingMessageParams (..),+    RootsListChangedNotification (..),++    -- * Union Types+    ClientRequest (..),+    ServerRequest (..),+    ClientNotification (..),+    ServerNotification (..),++    -- * MCP Constants+    pROTOCOL_VERSION,+) where++import Control.Applicative ((<|>))+import Data.Aeson+import Data.Aeson.TH+import Data.Map (Map)+import Data.Text (Text)+import GHC.Generics+import JSONRPC+import MCP.Aeson+import MCP.Types++-- * Client Request Types++{- | Initialize request parameters.++Parameters sent by the client during initialization.+-}+data InitializeParams = InitializeParams+    { protocolVersion :: Text+    {- ^ The latest version of the Model Context Protocol that the client supports.+    The client MAY decide to support older versions as well.+    -}+    , capabilities :: ClientCapabilities+    , clientInfo :: Implementation+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''InitializeParams)++{- | This request is sent from the client to the server when it first connects,+asking it to begin initialization.+-}+data InitializeRequest = InitializeRequest+    { id :: RequestId+    , params :: InitializeParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest InitializeRequest++instance IsJSONRPCRequest InitializeRequest where+    requestMethod _ = "initialize"++{- | Ping request parameters.++Parameters for a ping request (typically just metadata).+-}+data PingParams where+    PingParams :: {_meta :: Maybe Metadata} -> PingParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''PingParams)++{- | A ping, issued by either the server or the client, to check that the other+party is still alive.++The receiver must promptly respond, or else may be disconnected.+-}+data PingRequest = PingRequest+    { id :: RequestId+    , params :: Maybe PingParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest PingRequest++instance IsJSONRPCRequest PingRequest where+    requestMethod _ = "ping"++{- | List resources request parameters.++Parameters for requesting a paginated list of resources.+-}+data ListResourcesParams where+    ListResourcesParams ::+        { cursor :: Maybe Cursor+        {- ^ An opaque token representing the current pagination position.+        If provided, the server should return results starting after this cursor.+        -}+        } ->+        ListResourcesParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListResourcesParams)++-- | Sent from the client to request a list of resources the server has.+data ListResourcesRequest = ListResourcesRequest+    { id :: RequestId+    , params :: Maybe ListResourcesParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ListResourcesRequest++instance IsJSONRPCRequest ListResourcesRequest where+    requestMethod _ = "resources/list"++{- | List resource templates request parameters.++Parameters for requesting a paginated list of resource templates.+-}+data ListResourceTemplatesParams where+    ListResourceTemplatesParams ::+        { cursor :: Maybe Cursor+        {- ^ An opaque token representing the current pagination position.+        If provided, the server should return results starting after this cursor.+        -}+        } ->+        ListResourceTemplatesParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListResourceTemplatesParams)++-- | Sent from the client to request a list of resource templates the server has.+data ListResourceTemplatesRequest = ListResourceTemplatesRequest+    { id :: RequestId+    , params :: Maybe ListResourceTemplatesParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ListResourceTemplatesRequest++instance IsJSONRPCRequest ListResourceTemplatesRequest where+    requestMethod _ = "resources/templates/list"++{- | Read resource request parameters.++Parameters for reading a specific resource.+-}+data ReadResourceParams where+    ReadResourceParams ::+        { uri :: Text+        {- ^ The URI of the resource to read. The URI can use any protocol;+        it is up to the server how to interpret it.+        -}+        } ->+        ReadResourceParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ReadResourceParams)++-- | Sent from the client to the server, to read a specific resource URI.+data ReadResourceRequest = ReadResourceRequest+    { id :: RequestId+    , params :: ReadResourceParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ReadResourceRequest++instance IsJSONRPCRequest ReadResourceRequest where+    requestMethod _ = "resources/read"++{- | Subscribe request parameters.++Parameters for subscribing to resource updates.+-}+data SubscribeParams where+    SubscribeParams ::+        { uri :: Text+        {- ^ The URI of the resource to subscribe to. The URI can use any protocol;+        it is up to the server how to interpret it.+        -}+        } ->+        SubscribeParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''SubscribeParams)++{- | Sent from the client to request resources/updated notifications from the server+whenever a particular resource changes.+-}+data SubscribeRequest = SubscribeRequest+    { id :: RequestId+    , params :: SubscribeParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest SubscribeRequest++instance IsJSONRPCRequest SubscribeRequest where+    requestMethod _ = "resources/subscribe"++{- | Unsubscribe request parameters.++Parameters for unsubscribing from resource updates.+-}+data UnsubscribeParams where+    UnsubscribeParams ::+        { uri :: Text+        -- ^ The URI of the resource to unsubscribe from.+        } ->+        UnsubscribeParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''UnsubscribeParams)++{- | Sent from the client to request cancellation of resources/updated+notifications from the server. This should follow a previous resources/subscribe request.+-}+data UnsubscribeRequest = UnsubscribeRequest+    { id :: RequestId+    , params :: UnsubscribeParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest UnsubscribeRequest++instance IsJSONRPCRequest UnsubscribeRequest where+    requestMethod _ = "resources/unsubscribe"++{- | List prompts request parameters.++Parameters for requesting a paginated list of prompts.+-}+data ListPromptsParams where+    ListPromptsParams ::+        { cursor :: Maybe Cursor+        {- ^ An opaque token representing the current pagination position.+        If provided, the server should return results starting after this cursor.+        -}+        } ->+        ListPromptsParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListPromptsParams)++-- | Sent from the client to request a list of prompts and prompt templates the server has.+data ListPromptsRequest = ListPromptsRequest+    { id :: RequestId+    , params :: Maybe ListPromptsParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ListPromptsRequest++instance IsJSONRPCRequest ListPromptsRequest where+    requestMethod _ = "prompts/list"++{- | Get prompt request parameters.++Parameters for retrieving a specific prompt with optional arguments.+-}+data GetPromptParams = GetPromptParams+    { name :: Text+    -- ^ The name of the prompt or prompt template.+    , arguments :: Maybe (Map Text Text)+    -- ^ Arguments to use for templating the prompt.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''GetPromptParams)++-- | Used by the client to get a prompt provided by the server.+data GetPromptRequest = GetPromptRequest+    { id :: RequestId+    , params :: GetPromptParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest GetPromptRequest++instance IsJSONRPCRequest GetPromptRequest where+    requestMethod _ = "prompts/get"++{- | List tools request parameters.++Parameters for requesting a paginated list of tools.+-}+data ListToolsParams where+    ListToolsParams ::+        { cursor :: Maybe Cursor+        {- ^ An opaque token representing the current pagination position.+        If provided, the server should return results starting after this cursor.+        -}+        } ->+        ListToolsParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListToolsParams)++-- | Sent from the client to request a list of tools the server has.+data ListToolsRequest = ListToolsRequest+    { id :: RequestId+    , params :: Maybe ListToolsParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ListToolsRequest++instance IsJSONRPCRequest ListToolsRequest where+    requestMethod _ = "tools/list"++{- | Call tool request parameters.++Parameters for invoking a specific tool with arguments.+-}+data CallToolParams = CallToolParams+    { name :: Text+    , arguments :: Maybe (Map Text Value)+    }+    deriving stock (Show, Eq, Generic, Ord)++$(deriveJSON mcpParseOpts ''CallToolParams)++-- | Used by the client to invoke a tool provided by the server.+data CallToolRequest = CallToolRequest+    { id :: RequestId+    , params :: CallToolParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest CallToolRequest++instance IsJSONRPCRequest CallToolRequest where+    requestMethod _ = "tools/call"++{- | Set level request parameters.++Parameters for setting the logging level.+-}+data SetLevelParams where+    SetLevelParams ::+        { level :: LoggingLevel+        {- ^ The level of logging that the client wants to receive from the server.+        The server should send all logs at this level and higher (i.e., more severe)+        to the client as notifications/message.+        -}+        } ->+        SetLevelParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''SetLevelParams)++-- | A request from the client to the server, to enable or adjust logging.+data SetLevelRequest = SetLevelRequest+    { id :: RequestId+    , params :: SetLevelParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest SetLevelRequest++instance IsJSONRPCRequest SetLevelRequest where+    requestMethod _ = "logging/setLevel"++{- | Completion argument.++Represents an argument for completion requests.+-}+data CompletionArgument = CompletionArgument+    { name :: Text+    -- ^ The name of the argument.+    , value :: Text+    -- ^ The value of the argument to use for completion matching.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CompletionArgument)++{- | Reference to either a prompt or resource template.++Used in completion requests to specify what is being completed.+-}+data Reference+    = PromptRef PromptReference+    | ResourceTemplateRef ResourceTemplateReference+    deriving stock (Show, Eq, Generic)++instance ToJSON Reference where+    toJSON (PromptRef p) = toJSON p+    toJSON (ResourceTemplateRef r) = toJSON r++instance FromJSON Reference where+    parseJSON v =+        (PromptRef <$> parseJSON v)+            <|> (ResourceTemplateRef <$> parseJSON v)++-- | Context for completion requests+data CompletionContext = CompletionContext+    { arguments :: Maybe (Map Text Text)+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CompletionContext)++{- | Complete request parameters.++Parameters for requesting completion options.+-}+data CompleteParams = CompleteParams+    { ref :: Reference+    , argument :: CompletionArgument+    -- ^ The argument's information.+    , context :: Maybe CompletionContext+    {- ^ Additional, optional context for completions.+    Previously-resolved variables in a URI template or prompt.+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CompleteParams)++-- | A request from the client to the server, to ask for completion options.+data CompleteRequest = CompleteRequest+    { id :: RequestId+    , params :: CompleteParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest CompleteRequest++instance IsJSONRPCRequest CompleteRequest where+    requestMethod _ = "completion/complete"++-- * Server Request Types++{- | Create message request parameters.++Parameters for requesting LLM sampling from the client.+-}+data CreateMessageParams = CreateMessageParams+    { maxTokens :: Int+    {- ^ The maximum number of tokens to sample, as requested by the server.+    The client MAY choose to sample fewer tokens than requested.+    -}+    , messages :: [SamplingMessage]+    , modelPreferences :: Maybe ModelPreferences+    -- ^ The server's preferences for which model to select. The client MAY ignore these preferences.+    , systemPrompt :: Maybe Text+    {- ^ An optional system prompt the server wants to use for sampling.+    The client MAY modify or omit this prompt.+    -}+    , includeContext :: Maybe IncludeContext+    {- ^ A request to include context from one or more MCP servers (including the caller),+    to be attached to the prompt. The client MAY ignore this request.+    -}+    , temperature :: Maybe Double+    , stopSequences :: Maybe [Text]+    , metadata :: Maybe (Map Text Value)+    {- ^ Optional metadata to pass through to the LLM provider.+    The format of this metadata is provider-specific.+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CreateMessageParams)++{- | A request from the server to sample an LLM via the client.++The client has full discretion over which model to select. The client should also+inform the user before beginning sampling, to allow them to inspect the request+(human in the loop) and decide whether to approve it.+-}+data CreateMessageRequest = CreateMessageRequest+    { id :: RequestId+    , params :: CreateMessageParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest CreateMessageRequest++instance IsJSONRPCRequest CreateMessageRequest where+    requestMethod _ = "sampling/createMessage"++{- | List roots request parameters.++Parameters for requesting the list of root directories or files.+-}+data ListRootsParams where+    ListRootsParams :: {_meta :: Maybe Metadata} -> ListRootsParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListRootsParams)++{- | Sent from the server to request a list of root URIs from the client.++Roots allow servers to ask for specific directories or files to operate on.+A common example for roots is providing a set of repositories or directories+a server should operate on.++This request is typically used when the server needs to understand the file system+structure or access specific locations that the client has permission to read from.+-}+data ListRootsRequest = ListRootsRequest+    { id :: RequestId+    , params :: Maybe ListRootsParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ListRootsRequest++instance IsJSONRPCRequest ListRootsRequest where+    requestMethod _ = "roots/list"++-- * Response Types++-- | After receiving an initialize request from the client, the server sends this response.+data InitializeResult = InitializeResult+    { protocolVersion :: Text+    {- ^ The version of the Model Context Protocol that the server wants to use.+    This may not match the version that the client requested. If the client+    cannot support this version, it MUST disconnect.+    -}+    , capabilities :: ServerCapabilities+    , serverInfo :: Implementation+    , instructions :: Maybe Text+    {- ^ Instructions describing how to use the server and its features.+    This can be used by clients to improve the LLM's understanding of available+    tools, resources, etc. It can be thought of like a "hint" to the model.+    For example, this information MAY be added to the system prompt.+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''InitializeResult)++-- | The server's response to a resources/list request from the client.+data ListResourcesResult = ListResourcesResult+    { resources :: [Resource]+    , nextCursor :: Maybe Cursor+    {- ^ An opaque token representing the pagination position after the last returned result.+    If present, there may be more results available.+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListResourcesResult)++-- | The server's response to a resources/templates/list request from the client.+data ListResourceTemplatesResult = ListResourceTemplatesResult+    { resourceTemplates :: [ResourceTemplate]+    , nextCursor :: Maybe Cursor+    {- ^ An opaque token representing the pagination position after the last returned result.+    If present, there may be more results available.+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListResourceTemplatesResult)++-- | The server's response to a resources/read request from the client.+data ReadResourceResult = ReadResourceResult+    { contents :: [ResourceContents]+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ReadResourceResult)++-- | The server's response to a prompts/list request from the client.+data ListPromptsResult = ListPromptsResult+    { prompts :: [Prompt]+    , nextCursor :: Maybe Cursor+    {- ^ An opaque token representing the pagination position after the last returned result.+    If present, there may be more results available.+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListPromptsResult)++-- | The server's response to a prompts/get request from the client.+data GetPromptResult = GetPromptResult+    { description :: Maybe Text+    -- ^ An optional description for the prompt.+    , messages :: [PromptMessage]+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''GetPromptResult)++-- | The server's response to a tools/list request from the client.+data ListToolsResult = ListToolsResult+    { tools :: [Tool]+    , nextCursor :: Maybe Cursor+    {- ^ An opaque token representing the pagination position after the last returned result.+    If present, there may be more results available.+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListToolsResult)++{- | The server's response to a tool call.++Any errors that originate from the tool SHOULD be reported inside the result+object, with `isError` set to true, _not_ as an MCP protocol-level error+response. Otherwise, the LLM would not be able to see that an error occurred+and self-correct.++However, any errors in _finding_ the tool, an error indicating that the+server does not support tool calls, or any other exceptional conditions,+should be reported as an MCP error response.+-}+data CallToolResult = CallToolResult+    { content :: [ContentBlock]+    -- ^ A list of content objects that represent the unstructured result of the tool call.+    , structuredContent :: Maybe (Map Text Value)+    -- ^ An optional JSON object that represents the structured result of the tool call.+    , isError :: Maybe Bool+    {- ^ Whether the tool call ended in an error.+    If not set, this is assumed to be false (the call was successful).+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CallToolResult)++{- | Completion result inner type.++Contains the actual completion data.+-}+data CompletionResult = CompletionResult+    { values :: [Text]+    -- ^ An array of completion values. Must not exceed 100 items.+    , total :: Maybe Int+    {- ^ The total number of completion options available.+    This can exceed the number of values actually sent in the response.+    -}+    , hasMore :: Maybe Bool+    {- ^ Indicates whether there are additional completion options beyond those+    provided in the current response, even if the exact total is unknown.+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CompletionResult)++-- | The server's response to a completion/complete request.+data CompleteResult = CompleteResult+    { completion :: CompletionResult+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CompleteResult)++{- | The client's response to a sampling/createMessage request from the server.++The client should inform the user before returning the sampled message, to allow them+to inspect the response (human in the loop) and decide whether to allow the server to see it.+-}+data CreateMessageResult = CreateMessageResult+    { role :: Role+    , content :: Content -- This stays as Content for sampling, not ContentBlock+    , model :: Text+    -- ^ The name of the model that generated the message.+    , stopReason :: Maybe Text+    -- ^ The reason why sampling stopped, if known.+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CreateMessageResult)++{- | The client's response to a roots/list request from the server.++This result contains an array of Root objects, each representing a root directory+or file that the server can operate on.+-}+data ListRootsResult = ListRootsResult+    { roots :: [Root]+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ListRootsResult)++-- * Notification Types++{- | Cancelled notification parameters.++Parameters for a cancellation notification.+-}+data CancelledParams = CancelledParams+    { requestId :: RequestId+    {- ^ The ID of the request to cancel.+    This MUST correspond to the ID of a request previously issued in the same direction.+    -}+    , reason :: Maybe Text+    {- ^ An optional string describing the reason for the cancellation.+    This MAY be logged or presented to the user.+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''CancelledParams)++{- | This notification can be sent by either side to indicate that it is cancelling+a previously-issued request.++The request SHOULD still be in-flight, but due to communication latency, it is always+possible that this notification MAY arrive after the request has already finished.++This notification indicates that the result will be unused, so any associated+processing SHOULD cease.++A client MUST NOT attempt to cancel its `initialize` request.+-}+data CancelledNotification = CancelledNotification+    { params :: CancelledParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification CancelledNotification++instance IsJSONRPCNotification CancelledNotification where+    notificationsMethod _ = "notifications/cancelled"++{- | Initialized notification parameters.++Parameters for the initialized notification (typically just metadata).+-}+data InitializedParams where+    InitializedParams :: {_meta :: Maybe Metadata} -> InitializedParams+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''InitializedParams)++-- | This notification is sent from the client to the server after initialization has finished.+data InitializedNotification = InitializedNotification+    { params :: Maybe EmptyParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification InitializedNotification++instance IsJSONRPCNotification InitializedNotification where+    notificationsMethod _ = "notifications/initialized"++{- | Progress notification parameters.++Parameters for progress update notifications.+-}+data ProgressParams = ProgressParams+    { progressToken :: ProgressToken+    {- ^ The progress token which was given in the initial request, used to associate+    this notification with the request that is proceeding.+    -}+    , progress :: Double+    {- ^ The progress thus far. This should increase every time progress is made,+    even if the total is unknown.+    -}+    , total :: Maybe Double+    -- ^ Total number of items to process (or total progress required), if known.+    , message :: Maybe Text+    -- ^ An optional message describing the current progress.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ProgressParams)++{- | An out-of-band notification used to inform the receiver of a progress update+for a long-running request.+-}+data ProgressNotification = ProgressNotification+    { params :: ProgressParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification ProgressNotification++instance IsJSONRPCNotification ProgressNotification where+    notificationsMethod _ = "notifications/progress"++{- | An optional notification from the server to the client, informing it that the list+of resources it can read from has changed.++This may be issued by servers without any previous subscription from the client.+-}+data ResourceListChangedNotification = ResourceListChangedNotification+    { params :: Maybe EmptyParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification ResourceListChangedNotification++instance IsJSONRPCNotification ResourceListChangedNotification where+    notificationsMethod _ = "notifications/resources/list_changed"++{- | Resource updated notification parameters.++Parameters for resource update notifications.+-}+data ResourceUpdatedParams = ResourceUpdatedParams+    { uri :: Text+    {- ^ The URI of the resource that has been updated. This might be a sub-resource+    of the one that the client actually subscribed to.+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ResourceUpdatedParams)++{- | A notification from the server to the client, informing it that a resource+has changed and may need to be read again.++This should only be sent if the client previously sent a resources/subscribe request.+-}+data ResourceUpdatedNotification = ResourceUpdatedNotification+    { params :: ResourceUpdatedParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification ResourceUpdatedNotification++instance IsJSONRPCNotification ResourceUpdatedNotification where+    notificationsMethod _ = "notifications/resources/updated"++{- | An optional notification from the server to the client, informing it that the list+of prompts it offers has changed.++This may be issued by servers without any previous subscription from the client.+-}+data PromptListChangedNotification = PromptListChangedNotification+    { params :: Maybe EmptyParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification PromptListChangedNotification++instance IsJSONRPCNotification PromptListChangedNotification where+    notificationsMethod _ = "notifications/prompts/list_changed"++{- | An optional notification from the server to the client, informing it that the list+of tools it offers has changed.++This may be issued by servers without any previous subscription from the client.+-}+data ToolListChangedNotification = ToolListChangedNotification+    { params :: Maybe EmptyParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification ToolListChangedNotification++instance IsJSONRPCNotification ToolListChangedNotification where+    notificationsMethod _ = "notifications/tools/list_changed"++{- | Logging message notification parameters.++Parameters for log message notifications.+-}+data LoggingMessageParams = LoggingMessageParams+    { level :: LoggingLevel+    -- ^ The severity of this log message.+    , data' :: Value+    {- ^ The data to be logged, such as a string message or an object.+    Any JSON serializable type is allowed here.+    -}+    , logger :: Maybe Text+    -- ^ An optional name of the logger issuing this message.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''LoggingMessageParams)++{- | Notification of a log message passed from server to client.++If no logging/setLevel request has been sent from the client, the server MAY decide+which messages to send automatically.+-}+data LoggingMessageNotification = LoggingMessageNotification+    { params :: LoggingMessageParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification LoggingMessageNotification++instance IsJSONRPCNotification LoggingMessageNotification where+    notificationsMethod _ = "notifications/message"++{- | A notification from the client to the server, informing it that the list of roots has changed.++This notification should be sent whenever the client adds, removes, or modifies any root.+The server should then request an updated list of roots using the ListRootsRequest.+-}+data RootsListChangedNotification = RootsListChangedNotification+    { params :: Maybe EmptyParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCNotification RootsListChangedNotification++instance IsJSONRPCNotification RootsListChangedNotification where+    notificationsMethod _ = "notifications/roots/list_changed"++-- * Union Types++{- | Any request that can be sent from a client to a server.++This union type encompasses all possible client-to-server requests in the MCP protocol.+-}+data ClientRequest+    = InitializeReq InitializeRequest+    | PingReq PingRequest+    | ListResourcesReq ListResourcesRequest+    | ListResourceTemplatesReq ListResourceTemplatesRequest+    | ReadResourceReq ReadResourceRequest+    | SubscribeReq SubscribeRequest+    | UnsubscribeReq UnsubscribeRequest+    | ListPromptsReq ListPromptsRequest+    | GetPromptReq GetPromptRequest+    | ListToolsReq ListToolsRequest+    | CallToolReq CallToolRequest+    | SetLevelReq SetLevelRequest+    | CompleteReq CompleteRequest+    deriving stock (Show, Eq, Generic)++instance ToJSON ClientRequest where+    toJSON (InitializeReq r) = toJSON r+    toJSON (PingReq r) = toJSON r+    toJSON (ListResourcesReq r) = toJSON r+    toJSON (ListResourceTemplatesReq r) = toJSON r+    toJSON (ReadResourceReq r) = toJSON r+    toJSON (SubscribeReq r) = toJSON r+    toJSON (UnsubscribeReq r) = toJSON r+    toJSON (ListPromptsReq r) = toJSON r+    toJSON (GetPromptReq r) = toJSON r+    toJSON (ListToolsReq r) = toJSON r+    toJSON (CallToolReq r) = toJSON r+    toJSON (SetLevelReq r) = toJSON r+    toJSON (CompleteReq r) = toJSON r++instance FromJSON ClientRequest where+    parseJSON v =+        (InitializeReq <$> parseJSON v)+            <|> (PingReq <$> parseJSON v)+            <|> (ListResourcesReq <$> parseJSON v)+            <|> (ListResourceTemplatesReq <$> parseJSON v)+            <|> (ReadResourceReq <$> parseJSON v)+            <|> (SubscribeReq <$> parseJSON v)+            <|> (UnsubscribeReq <$> parseJSON v)+            <|> (ListPromptsReq <$> parseJSON v)+            <|> (GetPromptReq <$> parseJSON v)+            <|> (ListToolsReq <$> parseJSON v)+            <|> (CallToolReq <$> parseJSON v)+            <|> (SetLevelReq <$> parseJSON v)+            <|> (CompleteReq <$> parseJSON v)++{- | Any request that can be sent from a server to a client.++This union type encompasses all possible server-to-client requests in the MCP protocol.+-}+data ServerRequest+    = PingServerReq PingRequest+    | CreateMessageReq CreateMessageRequest+    | ListRootsReq ListRootsRequest+    | ElicitReq ElicitRequest+    deriving stock (Show, Eq, Generic)++instance ToJSON ServerRequest where+    toJSON (PingServerReq r) = toJSON r+    toJSON (CreateMessageReq r) = toJSON r+    toJSON (ListRootsReq r) = toJSON r+    toJSON (ElicitReq r) = toJSON r++instance FromJSON ServerRequest where+    parseJSON v =+        (PingServerReq <$> parseJSON v)+            <|> (CreateMessageReq <$> parseJSON v)+            <|> (ListRootsReq <$> parseJSON v)+            <|> (ElicitReq <$> parseJSON v)++{- | Any notification that can be sent from a client to a server.++This union type encompasses all possible client-to-server notifications in the MCP protocol.+-}+data ClientNotification+    = CancelledNotif CancelledNotification+    | InitializedNotif InitializedNotification+    | ProgressNotif ProgressNotification+    | RootsListChangedNotif RootsListChangedNotification+    deriving stock (Show, Eq, Generic)++instance ToJSON ClientNotification where+    toJSON (CancelledNotif n) = toJSON n+    toJSON (InitializedNotif n) = toJSON n+    toJSON (ProgressNotif n) = toJSON n+    toJSON (RootsListChangedNotif n) = toJSON n++instance FromJSON ClientNotification where+    parseJSON v =+        (CancelledNotif <$> parseJSON v)+            <|> (InitializedNotif <$> parseJSON v)+            <|> (ProgressNotif <$> parseJSON v)+            <|> (RootsListChangedNotif <$> parseJSON v)++{- | Any notification that can be sent from a server to a client.++This union type encompasses all possible server-to-client notifications in the MCP protocol.+-}+data ServerNotification+    = CancelledServerNotif CancelledNotification+    | ProgressServerNotif ProgressNotification+    | ResourceListChangedNotif ResourceListChangedNotification+    | ResourceUpdatedNotif ResourceUpdatedNotification+    | PromptListChangedNotif PromptListChangedNotification+    | ToolListChangedNotif ToolListChangedNotification+    | LoggingMessageNotif LoggingMessageNotification+    deriving stock (Show, Eq, Generic)++instance ToJSON ServerNotification where+    toJSON (CancelledServerNotif n) = toJSON n+    toJSON (ProgressServerNotif n) = toJSON n+    toJSON (ResourceListChangedNotif n) = toJSON n+    toJSON (ResourceUpdatedNotif n) = toJSON n+    toJSON (PromptListChangedNotif n) = toJSON n+    toJSON (ToolListChangedNotif n) = toJSON n+    toJSON (LoggingMessageNotif n) = toJSON n++instance FromJSON ServerNotification where+    parseJSON v =+        (CancelledServerNotif <$> parseJSON v)+            <|> (ProgressServerNotif <$> parseJSON v)+            <|> (ResourceListChangedNotif <$> parseJSON v)+            <|> (ResourceUpdatedNotif <$> parseJSON v)+            <|> (PromptListChangedNotif <$> parseJSON v)+            <|> (ToolListChangedNotif <$> parseJSON v)+            <|> (LoggingMessageNotif <$> parseJSON v)++{- | MCP protocol version string.++Indicates the version of the Model Context Protocol+that this implementation supports.+-}+pROTOCOL_VERSION :: Text+pROTOCOL_VERSION = "2025-06-18"++{- | Primitive schema definitions that only allow primitive types without nested objects or arrays.++Restricted schema definitions for elicitation requests.+-}+data PrimitiveSchemaDefinition+    = StringSchema+        { schemaType :: Text -- Always "string"+        , title :: Maybe Text+        , description :: Maybe Text+        , minLength :: Maybe Int+        , maxLength :: Maybe Int+        , format :: Maybe Text -- "email" | "uri" | "date" | "date-time"+        }+    | NumberSchema+        { schemaType :: Text -- "number" or "integer"+        , title :: Maybe Text+        , description :: Maybe Text+        , minimum :: Maybe Double+        , maximum :: Maybe Double+        }+    | BooleanSchema+        { schemaType :: Text -- Always "boolean"+        , title :: Maybe Text+        , description :: Maybe Text+        , defaultValue :: Maybe Bool+        }+    | EnumSchema+        { schemaType :: Text -- Always "string"+        , title :: Maybe Text+        , description :: Maybe Text+        , enum :: [Text]+        , enumNames :: Maybe [Text] -- Display names for enum values+        }+    deriving stock (Show, Eq, Generic)++instance ToJSON PrimitiveSchemaDefinition where+    toJSON (StringSchema ty ttl desc minL maxL fmt) =+        object $+            ["type" .= ty]+                <> maybe [] (\t -> ["title" .= t]) ttl+                <> maybe [] (\d -> ["description" .= d]) desc+                <> maybe [] (\ml -> ["minLength" .= ml]) minL+                <> maybe [] (\mx -> ["maxLength" .= mx]) maxL+                <> maybe [] (\f -> ["format" .= f]) fmt+    toJSON (NumberSchema ty ttl desc minV maxV) =+        object $+            ["type" .= ty]+                <> maybe [] (\t -> ["title" .= t]) ttl+                <> maybe [] (\d -> ["description" .= d]) desc+                <> maybe [] (\mn -> ["minimum" .= mn]) minV+                <> maybe [] (\mx -> ["maximum" .= mx]) maxV+    toJSON (BooleanSchema ty ttl desc defVal) =+        object $+            ["type" .= ty]+                <> maybe [] (\t -> ["title" .= t]) ttl+                <> maybe [] (\d -> ["description" .= d]) desc+                <> maybe [] (\dv -> ["default" .= dv]) defVal+    toJSON (EnumSchema ty ttl desc vals names) =+        object $+            [ "type" .= ty+            , "enum" .= vals+            ]+                <> maybe [] (\t -> ["title" .= t]) ttl+                <> maybe [] (\d -> ["description" .= d]) desc+                <> maybe [] (\en -> ["enumNames" .= en]) names++instance FromJSON PrimitiveSchemaDefinition where+    parseJSON = withObject "PrimitiveSchemaDefinition" $ \o -> do+        ty <- o .: "type"+        case ty of+            "string" -> do+                enums <- o .:? "enum"+                case enums of+                    Just vals ->+                        EnumSchema ty+                            <$> o .:? "title"+                            <*> o .:? "description"+                            <*> pure vals+                            <*> o .:? "enumNames"+                    Nothing ->+                        StringSchema ty+                            <$> o .:? "title"+                            <*> o .:? "description"+                            <*> o .:? "minLength"+                            <*> o .:? "maxLength"+                            <*> o .:? "format"+            "number" ->+                NumberSchema ty+                    <$> o .:? "title"+                    <*> o .:? "description"+                    <*> o .:? "minimum"+                    <*> o .:? "maximum"+            "integer" ->+                NumberSchema ty+                    <$> o .:? "title"+                    <*> o .:? "description"+                    <*> o .:? "minimum"+                    <*> o .:? "maximum"+            "boolean" ->+                BooleanSchema ty+                    <$> o .:? "title"+                    <*> o .:? "description"+                    <*> o .:? "default"+            _ -> fail $ "Unknown schema type: " <> show ty++{- | Elicit request parameters.++Parameters for requesting additional information from the user via the client.+-}+data ElicitParams = ElicitParams+    { message :: Text+    -- ^ The message to present to the user.+    , requestedSchema :: Map Text PrimitiveSchemaDefinition+    {- ^ A restricted subset of JSON Schema. Only top-level properties are allowed,+    without nesting. The schema type is always "object" with properties.+    -}+    , requiredFields :: Maybe [Text]+    -- ^ Required fields in the schema.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON ElicitParams where+    toJSON (ElicitParams msg schema reqFields) =+        object $+            [ "message" .= msg+            , "requestedSchema"+                .= object+                    ( [ "type" .= ("object" :: Text)+                      , "properties" .= schema+                      ]+                        <> maybe [] (\rf -> ["required" .= rf]) reqFields+                    )+            ]++instance FromJSON ElicitParams where+    parseJSON = withObject "ElicitParams" $ \o -> do+        msg <- o .: "message"+        schema <- o .: "requestedSchema"+        schemaProps <-+            withObject+                "requestedSchema"+                ( \so -> do+                    ty <- so .: "type"+                    if ty == ("object" :: Text)+                        then do+                            props <- so .: "properties"+                            reqFields <- so .:? "required"+                            pure (props, reqFields)+                        else fail "Expected requestedSchema type to be 'object'"+                )+                schema+        pure $ ElicitParams msg (fst schemaProps) (snd schemaProps)++-- | A request from the server to elicit additional information from the user via the client.+data ElicitRequest = ElicitRequest+    { id :: RequestId+    , params :: ElicitParams+    }+    deriving stock (Show, Eq, Generic)+    deriving (ToJSON, FromJSON) via ViaJSONRPCRequest ElicitRequest++instance IsJSONRPCRequest ElicitRequest where+    requestMethod _ = "elicitation/create"++-- | The client's response to an elicitation request.+data ElicitResult = ElicitResult+    { action :: Text+    {- ^ The user action in response to the elicitation.+    - "accept": User submitted the form/confirmed the action+    - "decline": User explicitly declined the action+    - "cancel": User dismissed without making an explicit choice+    -}+    , content :: Maybe (Map Text Value)+    {- ^ The submitted form data, only present when action is "accept".+    Contains values matching the requested schema.+    -}+    , _meta :: Maybe Metadata+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ElicitResult)

@@ -0,0 +1,1130 @@+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE DerivingStrategies #-}+{-# LANGUAGE DuplicateRecordFields #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE LambdaCase #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE TemplateHaskell #-}++{- |+Module      : MCP.Types+Description : Core types for the Model Context Protocol (MCP)+Copyright   : (C) 2025 DPella AB+License     : MPL-2.0+Maintainer  : matti@dpella.io, lobo@dpella.io+Stability   : experimental+Portability : GHC++This module defines the core types used in the Model Context Protocol (MCP),+including JSON-RPC message types, client/server capabilities, resources,+tools, prompts, and various request/response types.+-}+module MCP.Types (+    -- * Basic Types (re-exported from JSONRPC)+    RequestId (..),+    -- * Basic Types+    Role (..),+    Cursor (..),+    ProgressToken (..),+    LoggingLevel (..),++    -- * Content Types+    Annotations (..),+    TextContent (..),+    ImageContent (..),+    AudioContent (..),+    EmbeddedResource (..),+    ResourceLink (..),+    Content (..),+    ContentBlock (..),++    -- * Resource Types+    ResourceContents (..),+    TextResourceContents (..),+    BlobResourceContents (..),+    Resource (..),+    ResourceTemplate (..),+    ResourceReference (..),+    ResourceTemplateReference,++    -- * Tool Types+    ToolAnnotations (..),+    Tool (..),+    InputSchema (..),++    -- * Prompt Types+    PromptArgument (..),+    Prompt (..),+    PromptMessage (..),+    PromptReference (..),++    -- * Model Types+    ModelHint (..),+    ModelPreferences (..),+    IncludeContext (..),+    SamplingMessage (..),++    -- * Capability Types+    ClientCapabilities (..),+    ServerCapabilities (..),+    RootsCapability (..),+    PromptsCapability (..),+    ResourcesCapability (..),+    ToolsCapability (..),+    CompletionsCapability (..),+    LoggingCapability (..),+    SamplingCapability (..),+    ElicitationCapability (..),+    ExperimentalCapability (..),++    -- * Implementation Info+    BaseMetadata (..),+    Implementation (..),++    -- * Roots+    Root (..),++    -- * Result Types+    Result (..),+    Metadata (..),+) where++import Control.Applicative (Alternative ((<|>)))+import Data.Aeson hiding (Error, Result)+import Data.Aeson.TH+import Data.Map (Map)+import Data.Text (Text)+import GHC.Generics+import JSONRPC (RequestId (..))+import MCP.Aeson++{- | The sender or recipient of messages and data in a conversation.++This is used to identify whether content comes from the user or the assistant+in prompt messages and sampling requests.+-}+data Role = User | Assistant+    deriving stock (Show, Eq, Generic)++instance ToJSON Role where+    toJSON User = "user"+    toJSON Assistant = "assistant"++instance FromJSON Role where+    parseJSON = withText "Role" $ \case+        "user" -> pure User+        "assistant" -> pure Assistant+        other -> fail $ "Unknown role: " <> show other++{- | An opaque token used to represent a cursor for pagination.++Used in paginated requests to indicate the starting position for the next+set of results. If provided, the server should return results starting+after this cursor.+-}+newtype Cursor = Cursor Text+    deriving stock (Show, Eq)+    deriving newtype (ToJSON, FromJSON)++{- | A progress token, used to associate progress notifications with the original request.++If specified in a request, the caller is requesting out-of-band progress+notifications (as represented by notifications/progress). The value is an+opaque token that will be attached to any subsequent notifications.+The receiver is not obligated to provide these notifications.+-}+newtype ProgressToken = ProgressToken Value+    deriving stock (Show, Eq)+    deriving newtype (ToJSON, FromJSON)++{- | The severity of a log message.++These map to syslog message severities, as specified in RFC-5424:+https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1+-}+data LoggingLevel+    = Emergency+    | Alert+    | Critical+    | Error+    | Warning+    | Notice+    | Info+    | Debug+    deriving stock (Show, Ord, Eq, Generic)++instance ToJSON LoggingLevel where+    toJSON Emergency = "emergency"+    toJSON Alert = "alert"+    toJSON Critical = "critical"+    toJSON Error = "error"+    toJSON Warning = "warning"+    toJSON Notice = "notice"+    toJSON Info = "info"+    toJSON Debug = "debug"++instance FromJSON LoggingLevel where+    parseJSON = withText "LoggingLevel" $ \case+        "alert" -> pure Alert+        "critical" -> pure Critical+        "debug" -> pure Debug+        "emergency" -> pure Emergency+        "error" -> pure Error+        "info" -> pure Info+        "notice" -> pure Notice+        "warning" -> pure Warning+        other -> fail $ "Unknown logging level: " <> show other++{- | Optional annotations for the client.++The client can use annotations to inform how objects are used or displayed.+-}+data Annotations = Annotations+    { audience :: Maybe [Role]+    {- ^ Describes who the intended customer of this object or data is.+    It can include multiple entries to indicate content useful for+    multiple audiences (e.g., ["user", "assistant"]).+    -}+    , priority :: Maybe Double+    {- ^ Describes how important this data is for operating the server.+    A value of 1 means "most important," and indicates that the data is+    effectively required, while 0 means "least important," and indicates+    that the data is entirely optional. Range: 0.0 to 1.0+    -}+    , lastModified :: Maybe Text+    {- ^ The moment the resource was last modified, as an ISO 8601 formatted string.+    Should be an ISO 8601 formatted string (e.g., "2025-01-12T15:00:58Z").+    Examples: last activity timestamp in an open file, timestamp when the resource+    was attached, etc.+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''Annotations)++{- | Metadata for results.++This result property is reserved by the protocol to allow clients and servers+to attach additional metadata to their responses.+-}+newtype Metadata = Metadata (Map Text Value)+    deriving stock (Show, Eq, Generic)+    deriving newtype (ToJSON, FromJSON)++{- | Text provided to or from an LLM.++This represents textual content that can be sent to or received from+a language model during conversations.+-}+data TextContent = TextContent+    { textType :: Text -- Always "text"+    , text :: Text+    -- ^ The text content of the message.+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON TextContent where+    toJSON (TextContent _ txt anns m) =+        object $+            [ "type" .= ("text" :: Text)+            , "text" .= txt+            ]+                <> maybe [] (\a -> ["annotations" .= a]) anns+                <> maybe [] (\meta -> ["_meta" .= meta]) m++instance FromJSON TextContent where+    parseJSON = withObject "TextContent" $ \o -> do+        ty <- o .: "type"+        if ty == ("text" :: Text)+            then TextContent ty <$> o .: "text" <*> o .:? "annotations" <*> o .:? "_meta"+            else fail "Expected type 'text'"++{- | An image provided to or from an LLM.++Represents image data that can be included in messages to language models+that support multimodal input.+-}+data ImageContent = ImageContent+    { imageType :: Text -- Always "image"+    , data' :: Text+    -- ^ The base64-encoded image data.+    , mimeType :: Text+    -- ^ The MIME type of the image. Different providers may support different image types.+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON ImageContent where+    toJSON (ImageContent _ dat mime anns m) =+        object $+            [ "type" .= ("image" :: Text)+            , "data" .= dat+            , "mimeType" .= mime+            ]+                <> maybe [] (\a -> ["annotations" .= a]) anns+                <> maybe [] (\meta -> ["_meta" .= meta]) m++instance FromJSON ImageContent where+    parseJSON = withObject "ImageContent" $ \o -> do+        ty <- o .: "type"+        if ty == ("image" :: Text)+            then ImageContent ty <$> o .: "data" <*> o .: "mimeType" <*> o .:? "annotations" <*> o .:? "_meta"+            else fail "Expected type 'image'"++{- | Audio provided to or from an LLM.++Represents audio data that can be included in messages to language models+that support audio input.+-}+data AudioContent = AudioContent+    { audioType :: Text -- Always "audio"+    , data' :: Text+    -- ^ The base64-encoded audio data.+    , mimeType :: Text+    -- ^ The MIME type of the audio. Different providers may support different audio types.+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON AudioContent where+    toJSON (AudioContent _ dat mime anns m) =+        object $+            [ "type" .= ("audio" :: Text)+            , "data" .= dat+            , "mimeType" .= mime+            ]+                <> maybe [] (\a -> ["annotations" .= a]) anns+                <> maybe [] (\meta -> ["_meta" .= meta]) m++instance FromJSON AudioContent where+    parseJSON = withObject "AudioContent" $ \o -> do+        ty <- o .: "type"+        if ty == ("audio" :: Text)+            then AudioContent ty <$> o .: "data" <*> o .: "mimeType" <*> o .:? "annotations" <*> o .:? "_meta"+            else fail "Expected type 'audio'"++{- | Text resource contents.++Represents the contents of a resource that can be represented as text+(not binary data).+-}+data TextResourceContents = TextResourceContents+    { uri :: Text+    -- ^ The URI of this resource.+    , text :: Text+    {- ^ The text of the item. This must only be set if the item can+    actually be represented as text (not binary data).+    -}+    , mimeType :: Maybe Text+    -- ^ The MIME type of this resource, if known.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$( deriveJSON+    mcpParseOpts+    ''TextResourceContents+ )++{- | Blob resource contents.++Represents the contents of a resource as binary data, encoded in base64.+-}+data BlobResourceContents = BlobResourceContents+    { uri :: Text+    -- ^ The URI of this resource.+    , blob :: Text+    -- ^ A base64-encoded string representing the binary data of the item.+    , mimeType :: Maybe Text+    -- ^ The MIME type of this resource, if known.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$( deriveJSON+    mcpParseOpts+    ''BlobResourceContents+ )++{- | The contents of a specific resource or sub-resource.++A resource can contain either text or binary data.+-}+data ResourceContents+    = TextResource TextResourceContents+    | BlobResource BlobResourceContents+    deriving stock (Show, Eq, Generic)++instance ToJSON ResourceContents where+    toJSON (TextResource t) = toJSON t+    toJSON (BlobResource b) = toJSON b++instance FromJSON ResourceContents where+    parseJSON v =+        (TextResource <$> parseJSON v)+            <|> (BlobResource <$> parseJSON v)++{- | The contents of a resource, embedded into a prompt or tool call result.++It is up to the client how best to render embedded resources for the benefit+of the LLM and/or the user.+-}+data EmbeddedResource = EmbeddedResource+    { resourceType :: Text -- Always "resource"+    , resource :: ResourceContents+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON EmbeddedResource where+    toJSON (EmbeddedResource _ res anns m) =+        object $+            [ "type" .= ("resource" :: Text)+            , "resource" .= res+            ]+                <> maybe [] (\a -> ["annotations" .= a]) anns+                <> maybe [] (\meta -> ["_meta" .= meta]) m++instance FromJSON EmbeddedResource where+    parseJSON = withObject "EmbeddedResource" $ \o -> do+        ty <- o .: "type"+        if ty == ("resource" :: Text)+            then EmbeddedResource ty <$> o .: "resource" <*> o .:? "annotations" <*> o .:? "_meta"+            else fail "Expected type 'resource'"++{- | A resource that the server is capable of reading, included in a prompt or tool call result.++Note: resource links returned by tools are not guaranteed to appear in the results of `resources/list` requests.+-}+data ResourceLink = ResourceLink+    { linkType :: Text -- Always "resource_link"+    , uri :: Text+    -- ^ The URI of this resource.+    , name :: Text+    -- ^ A human-readable name for this resource.+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    , description :: Maybe Text+    -- ^ A description of what this resource represents.+    , mimeType :: Maybe Text+    -- ^ The MIME type of this resource, if known.+    , size :: Maybe Int+    -- ^ The size of the raw resource content, in bytes.+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON ResourceLink where+    toJSON (ResourceLink _ u n t d mt s a m) =+        object $+            [ "type" .= ("resource_link" :: Text)+            , "uri" .= u+            , "name" .= n+            ]+                <> maybe [] (\ttl -> ["title" .= ttl]) t+                <> maybe [] (\desc -> ["description" .= desc]) d+                <> maybe [] (\mime -> ["mimeType" .= mime]) mt+                <> maybe [] (\sz -> ["size" .= sz]) s+                <> maybe [] (\ann -> ["annotations" .= ann]) a+                <> maybe [] (\meta -> ["_meta" .= meta]) m++instance FromJSON ResourceLink where+    parseJSON = withObject "ResourceLink" $ \o -> do+        ty <- o .: "type"+        if ty == ("resource_link" :: Text)+            then+                ResourceLink ty+                    <$> o .: "uri"+                    <*> o .: "name"+                    <*> o .:? "title"+                    <*> o .:? "description"+                    <*> o .:? "mimeType"+                    <*> o .:? "size"+                    <*> o .:? "annotations"+                    <*> o .:? "_meta"+            else fail "Expected type 'resource_link'"++{- | Content that can be text, image, audio, or embedded resource.++This union type represents the different kinds of content that can be+included in messages, prompts, and tool results.+-}+data Content+    = TextContentType TextContent+    | ImageContentType ImageContent+    | AudioContentType AudioContent+    | EmbeddedResourceType EmbeddedResource+    deriving stock (Show, Eq, Generic)++instance ToJSON Content where+    toJSON (TextContentType c) = toJSON c+    toJSON (ImageContentType c) = toJSON c+    toJSON (AudioContentType c) = toJSON c+    toJSON (EmbeddedResourceType c) = toJSON c++instance FromJSON Content where+    parseJSON v =+        (TextContentType <$> parseJSON v)+            <|> (ImageContentType <$> parseJSON v)+            <|> (AudioContentType <$> parseJSON v)+            <|> (EmbeddedResourceType <$> parseJSON v)++{- | ContentBlock union type that includes ResourceLink.++This is the unified content type used in new schema version.+-}+data ContentBlock+    = TextBlock TextContent+    | ImageBlock ImageContent+    | AudioBlock AudioContent+    | ResourceLinkBlock ResourceLink+    | EmbeddedResourceBlock EmbeddedResource+    deriving stock (Show, Eq, Generic)++instance ToJSON ContentBlock where+    toJSON (TextBlock c) = toJSON c+    toJSON (ImageBlock c) = toJSON c+    toJSON (AudioBlock c) = toJSON c+    toJSON (ResourceLinkBlock c) = toJSON c+    toJSON (EmbeddedResourceBlock c) = toJSON c++instance FromJSON ContentBlock where+    parseJSON v =+        (TextBlock <$> parseJSON v)+            <|> (ImageBlock <$> parseJSON v)+            <|> (AudioBlock <$> parseJSON v)+            <|> (ResourceLinkBlock <$> parseJSON v)+            <|> (EmbeddedResourceBlock <$> parseJSON v)++{- | A known resource that the server is capable of reading.++Resources represent files, documents, or other data sources that the+server can provide to clients.+-}+data Resource = Resource+    { uri :: Text+    -- ^ The URI of this resource.+    , name :: Text+    {- ^ A human-readable name for this resource.+    This can be used by clients to populate UI elements.+    -}+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    , description :: Maybe Text+    {- ^ A description of what this resource represents.+    This can be used by clients to improve the LLM's understanding+    of available resources. It can be thought of like a "hint" to the model.+    -}+    , mimeType :: Maybe Text+    -- ^ The MIME type of this resource, if known.+    , size :: Maybe Int+    {- ^ The size of the raw resource content, in bytes (i.e., before base64+    encoding or any tokenization), if known. This can be used by Hosts+    to display file sizes and estimate context window usage.+    -}+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$( deriveJSON+    mcpParseOpts+    ''Resource+ )++{- | A template description for resources available on the server.++Resource templates allow servers to describe parameterized resources+that can be instantiated with specific values.+-}+data ResourceTemplate = ResourceTemplate+    { name :: Text+    {- ^ A human-readable name for the type of resource this template refers to.+    This can be used by clients to populate UI elements.+    -}+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    , uriTemplate :: Text+    -- ^ A URI template (according to RFC 6570) that can be used to construct resource URIs.+    , description :: Maybe Text+    {- ^ A description of what this template is for.+    This can be used by clients to improve the LLM's understanding+    of available resources. It can be thought of like a "hint" to the model.+    -}+    , mimeType :: Maybe Text+    {- ^ The MIME type for all resources that match this template.+    This should only be included if all resources matching this+    template have the same type.+    -}+    , annotations :: Maybe Annotations+    -- ^ Optional annotations for the client.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$( deriveJSON+    mcpParseOpts+    ''ResourceTemplate+ )++{- | A reference to a resource or resource template definition.++Used in completion requests and other contexts where a resource+needs to be referenced.+-}+data ResourceReference = ResourceReference+    { refType :: Text -- Always "ref/resource"+    , uri :: Text+    -- ^ The URI or URI template of the resource.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON ResourceReference where+    toJSON (ResourceReference _ u) =+        object+            [ "type" .= ("ref/resource" :: Text)+            , "uri" .= u+            ]++instance FromJSON ResourceReference where+    parseJSON = withObject "ResourceReference" $ \o -> do+        ty <- o .: "type"+        if ty == ("ref/resource" :: Text)+            then ResourceReference ty <$> o .: "uri"+            else fail "Expected type 'ref/resource'"++{- | A reference to a resource template definition.++This is an alias for ResourceReference in the new schema.+-}+type ResourceTemplateReference = ResourceReference++{- | Additional properties describing a Tool to clients.++NOTE: all properties in ToolAnnotations are **hints**.+They are not guaranteed to provide a faithful description of+tool behavior (including descriptive properties like `title`).++Clients should never make tool use decisions based on ToolAnnotations+received from untrusted servers.+-}+data ToolAnnotations = ToolAnnotations+    { title :: Maybe Text+    -- ^ A human-readable title for the tool.+    , readOnlyHint :: Maybe Bool+    -- ^ If true, the tool does not modify its environment. Default: false+    , destructiveHint :: Maybe Bool+    {- ^ If true, the tool may perform destructive updates to its environment.+    If false, the tool performs only additive updates.+    (This property is meaningful only when `readOnlyHint == false`)+    Default: true+    -}+    , idempotentHint :: Maybe Bool+    {- ^ If true, calling the tool repeatedly with the same arguments+    will have no additional effect on its environment.+    (This property is meaningful only when `readOnlyHint == false`)+    Default: false+    -}+    , openWorldHint :: Maybe Bool+    {- ^ If true, this tool may interact with an "open world" of external+    entities. If false, the tool's domain of interaction is closed.+    For example, the world of a web search tool is open, whereas that+    of a memory tool is not. Default: true+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ToolAnnotations)++{- | Input schema for a tool.++A JSON Schema object defining the expected parameters for the tool.+-}+data InputSchema = InputSchema+    { schemaType :: Text -- Always "object"+    , properties :: Maybe (Map Text Value)+    , required :: Maybe [Text]+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON InputSchema where+    toJSON (InputSchema _ props req) =+        object $+            [ "type" .= ("object" :: Text)+            ]+                <> maybe [] (\p -> ["properties" .= p]) props+                <> maybe [] (\r -> ["required" .= r]) req++instance FromJSON InputSchema where+    parseJSON = withObject "InputSchema" $ \o -> do+        ty <- o .: "type"+        if ty == ("object" :: Text)+            then InputSchema ty <$> o .:? "properties" <*> o .:? "required"+            else fail "Expected type 'object'"++{- | Definition for a tool the client can call.++Tools are functions that the MCP server exposes to clients,+allowing the client to perform specific actions or retrieve information.+-}+data Tool = Tool+    { name :: Text+    -- ^ The name of the tool.+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    , description :: Maybe Text+    {- ^ A human-readable description of the tool.+    This can be used by clients to improve the LLM's understanding+    of available tools. It can be thought of like a "hint" to the model.+    -}+    , inputSchema :: InputSchema+    -- ^ A JSON Schema object defining the expected parameters for the tool.+    , outputSchema :: Maybe InputSchema+    {- ^ An optional JSON Schema object defining the structure of the tool's output+    returned in the structuredContent field of a CallToolResult.+    -}+    , annotations :: Maybe ToolAnnotations+    {- ^ Optional additional tool information.+    Display name precedence order is: title, annotations.title, then name.+    -}+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''Tool)++{- | Describes an argument that a prompt can accept.++Prompt arguments allow prompts to be parameterized with user-provided values.+-}+data PromptArgument = PromptArgument+    { name :: Text+    -- ^ The name of the argument.+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    , description :: Maybe Text+    -- ^ A human-readable description of the argument.+    , required :: Maybe Bool+    -- ^ Whether this argument must be provided.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''PromptArgument)++{- | A prompt or prompt template that the server offers.++Prompts are reusable message templates that can be parameterized+with arguments to generate specific conversations.+-}+data Prompt = Prompt+    { name :: Text+    -- ^ The name of the prompt or prompt template.+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    , description :: Maybe Text+    -- ^ An optional description of what this prompt provides.+    , arguments :: Maybe [PromptArgument]+    -- ^ A list of arguments to use for templating the prompt.+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''Prompt)++{- | Describes a message returned as part of a prompt.++This is similar to `SamplingMessage`, but also supports the embedding of+resources from the MCP server.+-}+data PromptMessage = PromptMessage+    { role :: Role+    , content :: ContentBlock+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''PromptMessage)++{- | Identifies a prompt.++Used in completion requests and other contexts where a prompt+needs to be referenced.+-}+data PromptReference = PromptReference+    { refType :: Text -- Always "ref/prompt"+    , name :: Text+    -- ^ The name of the prompt or prompt template.+    , title :: Maybe Text+    -- ^ Optional title for display purposes.+    }+    deriving stock (Show, Eq, Generic)++instance ToJSON PromptReference where+    toJSON (PromptReference _ n t) =+        object $+            [ "type" .= ("ref/prompt" :: Text)+            , "name" .= n+            ]+                <> maybe [] (\ttl -> ["title" .= ttl]) t++instance FromJSON PromptReference where+    parseJSON = withObject "PromptReference" $ \o -> do+        ty <- o .: "type"+        if ty == ("ref/prompt" :: Text)+            then PromptReference ty <$> o .: "name" <*> o .:? "title"+            else fail "Expected type 'ref/prompt'"++{- | Hints to use for model selection.++Keys not declared here are currently left unspecified by the spec and are up+to the client to interpret.+-}+data ModelHint where+    ModelHint ::+        { name :: Maybe Text+        {- ^ A hint for a model name.+        The client SHOULD treat this as a substring of a model name; for example:+        - `claude-3-5-sonnet` should match `claude-3-5-sonnet-20241022`+        - `sonnet` should match `claude-3-5-sonnet-20241022`, `claude-3-sonnet-20240229`, etc.+        - `claude` should match any Claude model+        The client MAY also map the string to a different provider's model name+        or a different model family, as long as it fills a similar niche.+        -}+        } ->+        ModelHint+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ModelHint)++{- | The server's preferences for model selection, requested of the client during sampling.++Because LLMs can vary along multiple dimensions, choosing the "best" model is+rarely straightforward. Different models excel in different areas—some are+faster but less capable, others are more capable but more expensive, and so+on. This interface allows servers to express their priorities across multiple+dimensions to help clients make an appropriate selection for their use case.++These preferences are always advisory. The client MAY ignore them. It is also+up to the client to decide how to interpret these preferences and how to+balance them against other considerations.+-}+data ModelPreferences = ModelPreferences+    { hints :: Maybe [ModelHint]+    {- ^ Optional hints to use for model selection.+    If multiple hints are specified, the client MUST evaluate them in order+    (such that the first match is taken).+    The client SHOULD prioritize these hints over the numeric priorities, but+    MAY still use the priorities to select from ambiguous matches.+    -}+    , costPriority :: Maybe Double+    {- ^ How much to prioritize cost when selecting a model. A value of 0 means cost+    is not important, while a value of 1 means cost is the most important+    factor. Range: 0.0 to 1.0+    -}+    , speedPriority :: Maybe Double+    {- ^ How much to prioritize sampling speed (latency) when selecting a model. A+    value of 0 means speed is not important, while a value of 1 means speed is+    the most important factor. Range: 0.0 to 1.0+    -}+    , intelligencePriority :: Maybe Double+    {- ^ How much to prioritize intelligence and capabilities when selecting a+    model. A value of 0 means intelligence is not important, while a value of 1+    means intelligence is the most important factor. Range: 0.0 to 1.0+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ModelPreferences)++{- | Include context options for sampling.++A request to include context from one or more MCP servers (including the caller),+to be attached to the prompt. The client MAY ignore this request.+-}+data IncludeContext = AllServers | None | ThisServer+    deriving stock (Show, Eq, Generic)++instance ToJSON IncludeContext where+    toJSON AllServers = "allServers"+    toJSON None = "none"+    toJSON ThisServer = "thisServer"++instance FromJSON IncludeContext where+    parseJSON = withText "IncludeContext" $ \case+        "allServers" -> pure AllServers+        "none" -> pure None+        "thisServer" -> pure ThisServer+        other -> fail $ "Unknown include context: " <> show other++{- | Describes a message issued to or received from an LLM API.++Used in sampling requests to represent the conversation history+that should be sent to the language model.+-}+data SamplingMessage = SamplingMessage+    { role :: Role+    , content :: Content+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''SamplingMessage)++{- | Client capability for root directory management.++Present if the client supports listing roots (directories or files+that the server can operate on).+-}+data RootsCapability where+    RootsCapability ::+        { listChanged :: Maybe Bool+        -- ^ Whether the client supports notifications for changes to the roots list.+        } ->+        RootsCapability+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''RootsCapability)++{- | Server capability for prompt management.++Present if the server offers any prompt templates.+-}+data PromptsCapability where+    PromptsCapability ::+        { listChanged :: Maybe Bool+        -- ^ Whether this server supports notifications for changes to the prompt list.+        } ->+        PromptsCapability+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''PromptsCapability)++{- | Server capability for resource management.++Present if the server offers any resources to read.+-}+data ResourcesCapability = ResourcesCapability+    { listChanged :: Maybe Bool+    -- ^ Whether this server supports notifications for changes to the resource list.+    , subscribe :: Maybe Bool+    -- ^ Whether this server supports subscribing to resource updates.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ResourcesCapability)++{- | Server capability for tool management.++Present if the server offers any tools to call.+-}+data ToolsCapability where+    ToolsCapability ::+        { listChanged :: Maybe Bool+        -- ^ Whether this server supports notifications for changes to the tool list.+        } ->+        ToolsCapability+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ToolsCapability)++{- | Server capability for argument autocompletion.++Present if the server supports argument autocompletion suggestions.+-}+data CompletionsCapability = CompletionsCapability+    deriving stock (Show, Eq, Generic)++instance ToJSON CompletionsCapability where+    toJSON _ = object []++instance FromJSON CompletionsCapability where+    parseJSON = withObject "CompletionsCapability" $ \_ -> pure CompletionsCapability++{- | Server capability for logging.++Present if the server supports sending log messages to the client.+-}+data LoggingCapability = LoggingCapability+    deriving stock (Show, Eq, Generic)++instance ToJSON LoggingCapability where+    toJSON _ = object []++instance FromJSON LoggingCapability where+    parseJSON = withObject "LoggingCapability" $ \_ -> pure LoggingCapability++{- | Client capability for LLM sampling.++Present if the client supports sampling from an LLM.+-}+data SamplingCapability = SamplingCapability+    deriving stock (Show, Eq, Generic)++instance ToJSON SamplingCapability where+    toJSON _ = object []++instance FromJSON SamplingCapability where+    parseJSON = withObject "SamplingCapability" $ \_ -> pure SamplingCapability++{- | Experimental, non-standard capabilities.++Experimental capabilities that the client or server supports.+This is not a closed set: any client or server can define its own,+additional capabilities.+-}+newtype ExperimentalCapability = ExperimentalCapability (Map Text Value)+    deriving stock (Show, Eq, Generic)+    deriving newtype (ToJSON, FromJSON)++{- | Client capability for elicitation.++Present if the client supports elicitation from the server.+-}+data ElicitationCapability = ElicitationCapability+    deriving stock (Show, Eq, Generic)++instance ToJSON ElicitationCapability where+    toJSON _ = object []++instance FromJSON ElicitationCapability where+    parseJSON = withObject "ElicitationCapability" $ \_ -> pure ElicitationCapability++{- | Capabilities a client may support.++Known capabilities are defined here, in this schema, but this is not a closed set:+any client can define its own, additional capabilities.+-}+data ClientCapabilities = ClientCapabilities+    { roots :: Maybe RootsCapability+    -- ^ Present if the client supports listing roots.+    , sampling :: Maybe SamplingCapability+    -- ^ Present if the client supports sampling from an LLM.+    , elicitation :: Maybe ElicitationCapability+    -- ^ Present if the client supports elicitation from the server.+    , experimental :: Maybe ExperimentalCapability+    -- ^ Experimental, non-standard capabilities that the client supports.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ClientCapabilities)++{- | Capabilities that a server may support.++Known capabilities are defined here, in this schema, but this is not a closed set:+any server can define its own, additional capabilities.+-}+data ServerCapabilities = ServerCapabilities+    { logging :: Maybe LoggingCapability+    -- ^ Present if the server supports sending log messages to the client.+    , prompts :: Maybe PromptsCapability+    -- ^ Present if the server offers any prompt templates.+    , resources :: Maybe ResourcesCapability+    -- ^ Present if the server offers any resources to read.+    , tools :: Maybe ToolsCapability+    -- ^ Present if the server offers any tools to call.+    , completions :: Maybe CompletionsCapability+    -- ^ Present if the server supports argument autocompletion suggestions.+    , experimental :: Maybe ExperimentalCapability+    -- ^ Experimental, non-standard capabilities that the server supports.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''ServerCapabilities)++{- | Base interface for metadata with name (identifier) and title (display name) properties.++This is the base type for various entities that need both programmatic+identifiers and human-readable names.+-}+data BaseMetadata = BaseMetadata+    { name :: Text+    {- ^ Intended for programmatic or logical use, but used as a display name in past specs+    or fallback (if title isn't present).+    -}+    , title :: Maybe Text+    {- ^ Intended for UI and end-user contexts — optimized to be human-readable and easily understood,+    even by those unfamiliar with domain-specific terminology.+    If not provided, the name should be used for display (except for Tool,+    where `annotations.title` should be given precedence over using `name`,+    if present).+    -}+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''BaseMetadata)++{- | Describes the name and version of an MCP implementation.++Used to identify the client or server software in initialization.+-}+data Implementation = Implementation+    { name :: Text+    , version :: Text+    , title :: Maybe Text+    -- ^ Optional title for UI representation.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''Implementation)++{- | Represents a root directory or file that the server can operate on.++Roots allow servers to ask for specific directories or files to operate on.+A common example for roots is providing a set of repositories or directories+a server should operate on.+-}+data Root = Root+    { uri :: Text+    {- ^ The URI identifying the root. This *must* start with file:// for now.+    This restriction may be relaxed in future versions of the protocol to allow+    other URI schemes.+    -}+    , name :: Maybe Text+    {- ^ An optional name for the root. This can be used to provide a human-readable+    identifier for the root, which may be useful for display purposes or for+    referencing the root in other parts of the application.+    -}+    , _meta :: Maybe Metadata+    -- ^ Optional metadata field.+    }+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''Root)++{- | Base result type.++All MCP result types include optional metadata that can be used+to attach additional information to responses.+-}+data Result where+    Result ::+        { _meta :: Maybe Metadata+        {- ^ This result property is reserved by the protocol to allow clients and servers+        to attach additional metadata to their responses.+        -}+        } ->+        Result+    deriving stock (Show, Eq, Generic)++$(deriveJSON mcpParseOpts ''Result)

@@ -0,0 +1,494 @@+{-# LANGUAGE DuplicateRecordFields #-}+{-# LANGUAGE OverloadedStrings #-}++module Main (main) where++import Data.Aeson hiding (Error, Result)+import Data.Aeson.KeyMap qualified as KM+import Data.Map.Strict qualified as Map+import Data.Maybe (isNothing)+import JSONRPC ()+import MCP.Protocol+import MCP.Types+import Test.Hspec+import Prelude hiding (error, id, minimum, maximum)+import Prelude qualified++-- | Helper to extract a JSON Object, failing on non-objects.+asObject :: Value -> KM.KeyMap Value+asObject (Object o) = o+asObject _ = Prelude.error "expected object"++main :: IO ()+main = hspec $ do+    -- -----------------------------------------------------------------+    -- MCP.Types+    -- -----------------------------------------------------------------+    describe "MCP.Types" $ do+        describe "Role" $ do+            it "serialises User as \"user\"" $+                toJSON User `shouldBe` String "user"+            it "serialises Assistant as \"assistant\"" $+                toJSON Assistant `shouldBe` String "assistant"+            it "round-trips User" $+                decode (encode User) `shouldBe` Just User+            it "round-trips Assistant" $+                decode (encode Assistant) `shouldBe` Just Assistant+            it "rejects unknown role" $+                (decode "\"admin\"" :: Maybe Role) `shouldBe` Nothing++        describe "LoggingLevel" $ do+            it "round-trips all levels" $ do+                let levels = [Emergency, Alert, Critical, Error, Warning, Notice, Info, Debug]+                mapM_ (\l -> decode (encode l) `shouldBe` Just l) levels+            it "preserves ordering" $+                Emergency < Debug `shouldBe` True+            it "serialises Debug as \"debug\"" $+                toJSON Debug `shouldBe` String "debug"++        describe "Cursor" $ do+            it "round-trips" $ do+                let c = Cursor "abc123"+                decode (encode c) `shouldBe` Just c++        describe "ProgressToken" $ do+            it "round-trips a string token" $ do+                let t = ProgressToken (String "tok-1")+                decode (encode t) `shouldBe` Just t+            it "round-trips a numeric token" $ do+                let t = ProgressToken (Number 42)+                decode (encode t) `shouldBe` Just t++        describe "Annotations" $ do+            it "round-trips with all fields" $ do+                let ann = Annotations (Just [User, Assistant]) (Just 0.8) (Just "2025-01-12T15:00:58Z")+                decode (encode ann) `shouldBe` Just ann+            it "omits Nothing fields" $ do+                let ann = Annotations Nothing Nothing Nothing+                    obj = asObject (toJSON ann)+                KM.member "audience" obj `shouldBe` False+                KM.member "priority" obj `shouldBe` False++        describe "TextContent" $ do+            it "round-trips" $ do+                let tc = TextContent "text" "hello" Nothing Nothing+                decode (encode tc) `shouldBe` Just tc+            it "serialises type as \"text\"" $ do+                let tc = TextContent "text" "hello" Nothing Nothing+                    obj = asObject (toJSON tc)+                KM.lookup "type" obj `shouldBe` Just (String "text")+            it "rejects wrong type tag" $+                (decode "{\"type\":\"image\",\"text\":\"x\"}" :: Maybe TextContent) `shouldBe` Nothing++        describe "ImageContent" $ do+            it "round-trips" $ do+                let ic = ImageContent "image" "base64data" "image/png" Nothing Nothing+                decode (encode ic) `shouldBe` Just ic+            it "serialises data field (not data')" $ do+                let ic = ImageContent "image" "base64data" "image/png" Nothing Nothing+                    obj = asObject (toJSON ic)+                KM.member "data" obj `shouldBe` True+                KM.member "data'" obj `shouldBe` False++        describe "AudioContent" $ do+            it "round-trips" $ do+                let ac = AudioContent "audio" "base64audio" "audio/wav" Nothing Nothing+                decode (encode ac) `shouldBe` Just ac++        describe "ResourceContents" $ do+            it "round-trips TextResource" $ do+                let rc = TextResource (TextResourceContents "file:///a.txt" "contents" (Just "text/plain") Nothing)+                decode (encode rc) `shouldBe` Just rc+            it "round-trips BlobResource" $ do+                let rc = BlobResource (BlobResourceContents "file:///b.bin" "AQID" (Just "application/octet-stream") Nothing)+                decode (encode rc) `shouldBe` Just rc++        describe "EmbeddedResource" $ do+            it "round-trips" $ do+                let er = EmbeddedResource "resource" (TextResource (TextResourceContents "uri" "txt" Nothing Nothing)) Nothing Nothing+                decode (encode er) `shouldBe` Just er+            it "rejects wrong type tag" $+                (decode "{\"type\":\"text\",\"resource\":{}}" :: Maybe EmbeddedResource) `shouldBe` Nothing++        describe "ResourceLink" $ do+            it "round-trips with minimal fields" $ do+                let rl = ResourceLink "resource_link" "file:///x" "myfile" Nothing Nothing Nothing Nothing Nothing Nothing+                decode (encode rl) `shouldBe` Just rl+            it "round-trips with all fields" $ do+                let ann = Annotations (Just [User]) Nothing Nothing+                    rl = ResourceLink "resource_link" "file:///x" "myfile" (Just "My File") (Just "A file") (Just "text/plain") (Just 1024) (Just ann) Nothing+                decode (encode rl) `shouldBe` Just rl++        describe "Content (union)" $ do+            it "parses text content" $ do+                let js = "{\"type\":\"text\",\"text\":\"hello\"}"+                case decode js :: Maybe Content of+                    Just (TextContentType _) -> pure ()+                    other -> expectationFailure $ "Expected TextContentType, got: " <> show other+            it "parses image content" $ do+                let js = "{\"type\":\"image\",\"data\":\"abc\",\"mimeType\":\"image/png\"}"+                case decode js :: Maybe Content of+                    Just (ImageContentType _) -> pure ()+                    other -> expectationFailure $ "Expected ImageContentType, got: " <> show other++        describe "ContentBlock (union)" $ do+            it "parses resource_link as ResourceLinkBlock" $ do+                let js = "{\"type\":\"resource_link\",\"uri\":\"file:///x\",\"name\":\"f\"}"+                case decode js :: Maybe ContentBlock of+                    Just (ResourceLinkBlock _) -> pure ()+                    other -> expectationFailure $ "Expected ResourceLinkBlock, got: " <> show other++        describe "Resource" $ do+            it "round-trips with minimal fields" $ do+                let r = Resource "file:///a" "a" Nothing Nothing Nothing Nothing Nothing Nothing+                decode (encode r) `shouldBe` Just r+            it "omits Nothing fields" $ do+                let r = Resource "file:///a" "a" Nothing Nothing Nothing Nothing Nothing Nothing+                    obj = asObject (toJSON r)+                KM.member "description" obj `shouldBe` False+                KM.member "mimeType" obj `shouldBe` False++        describe "ResourceTemplate" $ do+            it "round-trips" $ do+                let rt = ResourceTemplate "tmpl" Nothing "file:///{path}" Nothing Nothing Nothing Nothing+                decode (encode rt) `shouldBe` Just rt++        describe "ResourceReference" $ do+            it "serialises type as \"ref/resource\"" $ do+                let rr = ResourceReference "ref/resource" "file:///a"+                    obj = asObject (toJSON rr)+                KM.lookup "type" obj `shouldBe` Just (String "ref/resource")+            it "round-trips" $ do+                let rr = ResourceReference "ref/resource" "file:///a"+                decode (encode rr) `shouldBe` Just rr+            it "rejects wrong type" $+                (decode "{\"type\":\"ref/prompt\",\"uri\":\"x\"}" :: Maybe ResourceReference) `shouldBe` Nothing++        describe "Tool" $ do+            it "round-trips" $ do+                let sch = InputSchema "object" (Just (Map.fromList [("x", object ["type" .= ("integer" :: String)])])) (Just ["x"])+                    t = Tool "add" Nothing (Just "Add numbers") sch Nothing Nothing Nothing+                decode (encode t) `shouldBe` Just t++        describe "InputSchema" $ do+            it "serialises type as \"object\"" $ do+                let s = InputSchema "object" Nothing Nothing+                    obj = asObject (toJSON s)+                KM.lookup "type" obj `shouldBe` Just (String "object")+            it "round-trips with properties" $ do+                let s = InputSchema "object" (Just (Map.singleton "a" (String "test"))) (Just ["a"])+                decode (encode s) `shouldBe` Just s++        describe "Prompt" $ do+            it "round-trips" $ do+                let p = Prompt "greet" Nothing (Just "A greeting") (Just [PromptArgument "name" Nothing Nothing (Just True)]) Nothing+                decode (encode p) `shouldBe` Just p++        describe "PromptReference" $ do+            it "serialises type as \"ref/prompt\"" $ do+                let pr = PromptReference "ref/prompt" "greet" Nothing+                    obj = asObject (toJSON pr)+                KM.lookup "type" obj `shouldBe` Just (String "ref/prompt")+            it "round-trips" $ do+                let pr = PromptReference "ref/prompt" "greet" (Just "Greeting")+                decode (encode pr) `shouldBe` Just pr++        describe "IncludeContext" $ do+            it "round-trips AllServers" $+                decode (encode AllServers) `shouldBe` Just AllServers+            it "round-trips None" $+                decode (encode None) `shouldBe` Just None+            it "round-trips ThisServer" $+                decode (encode ThisServer) `shouldBe` Just ThisServer++        describe "ModelHint" $ do+            it "round-trips" $ do+                let h = ModelHint (Just "claude-3-5-sonnet")+                decode (encode h) `shouldBe` Just h++        describe "ModelPreferences" $ do+            it "round-trips" $ do+                let mp = ModelPreferences (Just [ModelHint (Just "sonnet")]) (Just 0.5) (Just 0.8) (Just 0.9)+                decode (encode mp) `shouldBe` Just mp++        describe "Capabilities" $ do+            it "round-trips ClientCapabilities" $ do+                let cc = ClientCapabilities (Just (RootsCapability (Just True))) (Just SamplingCapability) Nothing Nothing+                decode (encode cc) `shouldBe` Just cc+            it "round-trips ServerCapabilities" $ do+                let sc = ServerCapabilities (Just LoggingCapability) (Just (PromptsCapability (Just True))) Nothing (Just (ToolsCapability Nothing)) (Just CompletionsCapability) Nothing+                decode (encode sc) `shouldBe` Just sc+            it "empty capabilities round-trip" $ do+                let cc = ClientCapabilities Nothing Nothing Nothing Nothing+                decode (encode cc) `shouldBe` Just cc++        describe "Implementation" $ do+            it "round-trips" $ do+                let impl = Implementation "test-server" "1.0.0" (Just "Test Server")+                decode (encode impl) `shouldBe` Just impl+            it "omits Nothing title" $ do+                let impl = Implementation "srv" "0.1" Nothing+                    obj = asObject (toJSON impl)+                KM.member "title" obj `shouldBe` False++        describe "Root" $ do+            it "round-trips" $ do+                let r = Root "file:///home/user" (Just "Home") Nothing+                decode (encode r) `shouldBe` Just r++        describe "Result" $ do+            it "round-trips with no metadata" $ do+                let r = Result Nothing+                decode (encode r) `shouldBe` Just r+            it "round-trips with metadata" $ do+                let m = Metadata (Map.singleton "key" (String "val"))+                    r = Result (Just m)+                decode (encode r) `shouldBe` Just r++    -- -----------------------------------------------------------------+    -- MCP.Protocol+    -- -----------------------------------------------------------------+    describe "MCP.Protocol" $ do+        describe "pROTOCOL_VERSION" $ do+            it "is \"2025-06-18\"" $+                pROTOCOL_VERSION `shouldBe` "2025-06-18"++        describe "InitializeRequest" $ do+            it "round-trips" $ do+                let initParams = InitializeParams "2025-06-18" (ClientCapabilities Nothing Nothing Nothing Nothing) (Implementation "client" "1.0" Nothing)+                    initReq = InitializeRequest (RequestId (Number 1)) initParams+                decode (encode initReq) `shouldBe` Just initReq+            it "serialises with method \"initialize\"" $ do+                let initParams = InitializeParams "2025-06-18" (ClientCapabilities Nothing Nothing Nothing Nothing) (Implementation "c" "1" Nothing)+                    initReq = InitializeRequest (RequestId (Number 1)) initParams+                    obj = asObject (toJSON initReq)+                KM.lookup "method" obj `shouldBe` Just (String "initialize")++        describe "PingRequest" $ do+            it "round-trips" $ do+                let pingReq = PingRequest (RequestId (Number 2)) Nothing+                decode (encode pingReq) `shouldBe` Just pingReq+            it "has method \"ping\"" $ do+                let obj = asObject (toJSON (PingRequest (RequestId (Number 1)) Nothing))+                KM.lookup "method" obj `shouldBe` Just (String "ping")++        describe "ListToolsRequest" $ do+            it "has method \"tools/list\"" $ do+                let obj = asObject (toJSON (ListToolsRequest (RequestId (Number 1)) Nothing))+                KM.lookup "method" obj `shouldBe` Just (String "tools/list")++        describe "CallToolRequest" $ do+            it "round-trips" $ do+                let callParams = CallToolParams "add" (Just (Map.fromList [("a", Number 1), ("b", Number 2)]))+                    callReq = CallToolRequest (RequestId (Number 3)) callParams+                decode (encode callReq) `shouldBe` Just callReq+            it "has method \"tools/call\"" $ do+                let callParams = CallToolParams "echo" Nothing+                    obj = asObject (toJSON (CallToolRequest (RequestId (Number 1)) callParams))+                KM.lookup "method" obj `shouldBe` Just (String "tools/call")++        describe "ListResourcesRequest" $ do+            it "has method \"resources/list\"" $ do+                let obj = asObject (toJSON (ListResourcesRequest (RequestId (Number 1)) Nothing))+                KM.lookup "method" obj `shouldBe` Just (String "resources/list")++        describe "ReadResourceRequest" $ do+            it "round-trips" $ do+                let readReq = ReadResourceRequest (RequestId (Number 4)) (ReadResourceParams "file:///a.txt")+                decode (encode readReq) `shouldBe` Just readReq++        describe "ListPromptsRequest" $ do+            it "has method \"prompts/list\"" $ do+                let obj = asObject (toJSON (ListPromptsRequest (RequestId (Number 1)) Nothing))+                KM.lookup "method" obj `shouldBe` Just (String "prompts/list")++        describe "GetPromptRequest" $ do+            it "round-trips" $ do+                let gpParams = GetPromptParams "greet" (Just (Map.singleton "name" "Alice"))+                    gpReq = GetPromptRequest (RequestId (Number 5)) gpParams+                decode (encode gpReq) `shouldBe` Just gpReq++        describe "SetLevelRequest" $ do+            it "round-trips" $ do+                let slReq = SetLevelRequest (RequestId (Number 6)) (SetLevelParams Warning)+                decode (encode slReq) `shouldBe` Just slReq++        describe "CompleteRequest" $ do+            it "round-trips" $ do+                let compParams = CompleteParams (PromptRef (PromptReference "ref/prompt" "greet" Nothing)) (CompletionArgument "name" "Al") Nothing+                    compReq = CompleteRequest (RequestId (Number 7)) compParams+                decode (encode compReq) `shouldBe` Just compReq++        describe "Response types" $ do+            it "InitializeResult round-trips" $ do+                let sc = ServerCapabilities Nothing Nothing Nothing (Just (ToolsCapability Nothing)) Nothing Nothing+                    res = InitializeResult "2025-06-18" sc (Implementation "srv" "1.0" Nothing) (Just "Use tools") Nothing+                decode (encode res) `shouldBe` Just res++            it "ListToolsResult round-trips" $ do+                let sch = InputSchema "object" Nothing Nothing+                    t = Tool "echo" Nothing (Just "Echo back") sch Nothing Nothing Nothing+                    res = ListToolsResult [t] Nothing Nothing+                decode (encode res) `shouldBe` Just res++            it "CallToolResult round-trips" $ do+                let res = CallToolResult [TextBlock (TextContent "text" "ok" Nothing Nothing)] Nothing Nothing Nothing+                decode (encode res) `shouldBe` Just res++            it "CallToolResult with isError round-trips" $ do+                let res = CallToolResult [TextBlock (TextContent "text" "fail" Nothing Nothing)] Nothing (Just True) Nothing+                decode (encode res) `shouldBe` Just res++            it "ListResourcesResult round-trips" $ do+                let r = Resource "file:///a" "a" Nothing Nothing Nothing Nothing Nothing Nothing+                    res = ListResourcesResult [r] Nothing Nothing+                decode (encode res) `shouldBe` Just res++            it "ReadResourceResult round-trips" $ do+                let rc = TextResource (TextResourceContents "file:///a" "hello" Nothing Nothing)+                    res = ReadResourceResult [rc] Nothing+                decode (encode res) `shouldBe` Just res++            it "CompleteResult round-trips" $ do+                let cr = CompletionResult ["Alice", "Alex"] (Just 2) Nothing+                    res = CompleteResult cr Nothing+                decode (encode res) `shouldBe` Just res++            it "GetPromptResult round-trips" $ do+                let pm = PromptMessage User (TextBlock (TextContent "text" "Hello!" Nothing Nothing))+                    res = GetPromptResult (Just "A prompt") [pm] Nothing+                decode (encode res) `shouldBe` Just res++        describe "Notification types" $ do+            it "InitializedNotification round-trips" $ do+                let n = InitializedNotification Nothing+                decode (encode n) `shouldBe` Just n+            it "InitializedNotification has correct method" $ do+                let obj = asObject (toJSON (InitializedNotification Nothing))+                KM.lookup "method" obj `shouldBe` Just (String "notifications/initialized")++            it "CancelledNotification round-trips" $ do+                let n = CancelledNotification (CancelledParams (RequestId (Number 5)) (Just "no longer needed"))+                decode (encode n) `shouldBe` Just n++            it "ProgressNotification round-trips" $ do+                let n = ProgressNotification (ProgressParams (ProgressToken (String "tok-1")) 0.5 (Just 1.0) (Just "halfway"))+                decode (encode n) `shouldBe` Just n++            it "LoggingMessageNotification round-trips" $ do+                let n = LoggingMessageNotification (LoggingMessageParams Info (String "server started") (Just "main"))+                decode (encode n) `shouldBe` Just n++            it "ResourceUpdatedNotification round-trips" $ do+                let n = ResourceUpdatedNotification (ResourceUpdatedParams "file:///a.txt")+                decode (encode n) `shouldBe` Just n++        describe "ClientRequest (union)" $ do+            it "parses an initialize request" $ do+                let initParams = InitializeParams "2025-06-18" (ClientCapabilities Nothing Nothing Nothing Nothing) (Implementation "c" "1" Nothing)+                    initReq = InitializeReq (InitializeRequest (RequestId (Number 1)) initParams)+                case decode (encode initReq) :: Maybe ClientRequest of+                    Just (InitializeReq _) -> pure ()+                    other -> expectationFailure $ "Expected InitializeReq, got: " <> show other++            it "parses a ping request" $ do+                let pingReq = PingReq (PingRequest (RequestId (Number 2)) Nothing)+                case decode (encode pingReq) :: Maybe ClientRequest of+                    Just (PingReq _) -> pure ()+                    other -> expectationFailure $ "Expected PingReq, got: " <> show other++            it "parses a tools/call request" $ do+                let callReq = CallToolReq (CallToolRequest (RequestId (Number 3)) (CallToolParams "echo" Nothing))+                case decode (encode callReq) :: Maybe ClientRequest of+                    Just (CallToolReq _) -> pure ()+                    other -> expectationFailure $ "Expected CallToolReq, got: " <> show other++        describe "ClientNotification (union)" $ do+            it "parses an initialized notification" $ do+                let n = InitializedNotif (InitializedNotification Nothing)+                case decode (encode n) :: Maybe ClientNotification of+                    Just (InitializedNotif _) -> pure ()+                    other -> expectationFailure $ "Expected InitializedNotif, got: " <> show other++        describe "ServerNotification (union)" $ do+            it "parses a logging message notification" $ do+                let n = LoggingMessageNotif (LoggingMessageNotification (LoggingMessageParams Debug (String "msg") Nothing))+                case decode (encode n) :: Maybe ServerNotification of+                    Just (LoggingMessageNotif _) -> pure ()+                    other -> expectationFailure $ "Expected LoggingMessageNotif, got: " <> show other++        describe "PrimitiveSchemaDefinition" $ do+            it "round-trips StringSchema" $ do+                let s = StringSchema "string" (Just "Name") Nothing Nothing (Just 100) (Just "email")+                decode (encode s) `shouldBe` Just s+            it "round-trips NumberSchema" $ do+                let s = NumberSchema "number" Nothing (Just "A number") (Just 0) (Just 100)+                decode (encode s) `shouldBe` Just s+            it "round-trips integer NumberSchema" $ do+                let s = NumberSchema "integer" Nothing Nothing Nothing Nothing+                decode (encode s) `shouldBe` Just s+            it "round-trips BooleanSchema" $ do+                let s = BooleanSchema "boolean" Nothing Nothing (Just True)+                decode (encode s) `shouldBe` Just s+            it "round-trips EnumSchema" $ do+                let s = EnumSchema "string" Nothing Nothing ["a", "b", "c"] (Just ["Alpha", "Beta", "Charlie"])+                decode (encode s) `shouldBe` Just s++        describe "ElicitParams" $ do+            it "round-trips" $ do+                let sch = Map.singleton "name" (StringSchema "string" (Just "Name") Nothing Nothing Nothing Nothing)+                    ep = ElicitParams "Enter your name" sch (Just ["name"])+                decode (encode ep) `shouldBe` Just ep+            it "wraps schema in object with type and properties" $ do+                let sch = Map.singleton "age" (NumberSchema "integer" Nothing Nothing Nothing Nothing)+                    ep = ElicitParams "Age?" sch Nothing+                    obj = asObject (toJSON ep)+                case KM.lookup "requestedSchema" obj of+                    Just (Object so) -> do+                        KM.lookup "type" so `shouldBe` Just (String "object")+                        KM.member "properties" so `shouldBe` True+                    other -> expectationFailure $ "Expected requestedSchema object, got: " <> show other++        describe "ElicitResult" $ do+            it "round-trips accept with content" $ do+                let res = ElicitResult "accept" (Just (Map.singleton "name" (String "Alice"))) Nothing+                decode (encode res) `shouldBe` Just res+            it "round-trips decline without content" $ do+                let res = ElicitResult "decline" Nothing Nothing+                decode (encode res) `shouldBe` Just res++    -- -----------------------------------------------------------------+    -- MCP.Aeson+    -- -----------------------------------------------------------------+    describe "MCP.Aeson" $ do+        describe "omitNothingFields" $ do+            it "omits Nothing fields from TH-derived types" $ do+                let impl = Implementation "srv" "1.0" Nothing+                    obj = asObject (toJSON impl)+                KM.member "title" obj `shouldBe` False+            it "includes Just fields" $ do+                let impl = Implementation "srv" "1.0" (Just "Server")+                    obj = asObject (toJSON impl)+                KM.lookup "title" obj `shouldBe` Just (String "Server")++        describe "_meta field" $ do+            it "serialises _meta as \"_meta\" (not modified)" $ do+                let r = Root "file:///a" Nothing (Just (Metadata (Map.singleton "k" (String "v"))))+                    obj = asObject (toJSON r)+                KM.member "_meta" obj `shouldBe` True+            it "omits _meta when Nothing" $ do+                let r = Root "file:///a" Nothing Nothing+                    obj = asObject (toJSON r)+                KM.member "_meta" obj `shouldBe` False+            it "parses _meta from JSON" $ do+                let js = "{\"uri\":\"file:///a\",\"_meta\":{\"k\":\"v\"}}"+                case decode js :: Maybe Root of+                    Just (Root _ _ meta) -> isNothing meta `shouldBe` False+                    Nothing -> expectationFailure "Failed to parse Root"++        describe "$sel: prefix stripping" $ do+            it "strips $sel: prefix for DuplicateRecordFields" $ do+                let sch = InputSchema "object" Nothing Nothing+                    t = Tool "echo" Nothing Nothing sch Nothing Nothing Nothing+                    obj = asObject (toJSON t)+                KM.member "name" obj `shouldBe` True