diff --git a/data/api/merge-requests/single-merge-request2.json b/data/api/merge-requests/single-merge-request2.json
new file mode 100644
--- /dev/null
+++ b/data/api/merge-requests/single-merge-request2.json
@@ -0,0 +1,125 @@
+{
+  "id": 18468,
+  "iid": 16018,
+  "project_id": 1,
+  "title": "users-guide: Fix weird notation in \"Summary of stolen syntax\"",
+  "description": "Fixes #26869",
+  "state": "closed",
+  "created_at": "2026-05-11T18:43:41.85Z",
+  "updated_at": "2026-05-18T14:22:27.43Z",
+  "merged_by": null,
+  "merge_user": null,
+  "merged_at": null,
+  "closed_by": {
+    "id": 94751,
+    "username": "meritamen",
+    "public_email": "meritamen@sdf.org",
+    "name": "Mrjtjmn",
+    "state": "active",
+    "locked": false,
+    "avatar_url": "https://gitlab.haskell.org/uploads/-/system/user/avatar/94751/avatar.png",
+    "web_url": "https://gitlab.haskell.org/meritamen"
+  },
+  "closed_at": "2026-05-18T13:16:33.016Z",
+  "target_branch": "master",
+  "source_branch": "master",
+  "user_notes_count": 6,
+  "upvotes": 1,
+  "downvotes": 0,
+  "author": {
+    "id": 94751,
+    "username": "meritamen",
+    "public_email": "meritamen@sdf.org",
+    "name": "Mrjtjmn",
+    "state": "active",
+    "locked": false,
+    "avatar_url": "https://gitlab.haskell.org/uploads/-/system/user/avatar/94751/avatar.png",
+    "web_url": "https://gitlab.haskell.org/meritamen"
+  },
+  "assignees": [
+    {
+      "id": 94751,
+      "username": "meritamen",
+      "public_email": "meritamen@sdf.org",
+      "name": "Mrjtjmn",
+      "state": "active",
+      "locked": false,
+      "avatar_url": "https://gitlab.haskell.org/uploads/-/system/user/avatar/94751/avatar.png",
+      "web_url": "https://gitlab.haskell.org/meritamen"
+    }
+  ],
+  "assignee": {
+    "id": 94751,
+    "username": "meritamen",
+    "public_email": "meritamen@sdf.org",
+    "name": "Mrjtjmn",
+    "state": "active",
+    "locked": false,
+    "avatar_url": "https://gitlab.haskell.org/uploads/-/system/user/avatar/94751/avatar.png",
+    "web_url": "https://gitlab.haskell.org/meritamen"
+  },
+  "reviewers": [],
+  "source_project_id": null,
+  "target_project_id": 1,
+  "labels": [
+    "documentation",
+    "no-changelog"
+  ],
+  "draft": false,
+  "imported": false,
+  "imported_from": "none",
+  "work_in_progress": false,
+  "milestone": null,
+  "merge_when_pipeline_succeeds": false,
+  "merge_status": "can_be_merged",
+  "detailed_merge_status": "not_open",
+  "merge_after": null,
+  "sha": "8cfc3a9241d9a178437ea10804384cd7125cd4e9",
+  "merge_commit_sha": null,
+  "squash_commit_sha": null,
+  "discussion_locked": null,
+  "should_remove_source_branch": null,
+  "force_remove_source_branch": null,
+  "prepared_at": "2026-05-11T18:43:55.731Z",
+  "allow_collaboration": false,
+  "allow_maintainer_to_push": false,
+  "reference": "!16018",
+  "references": {
+    "short": "!16018",
+    "relative": "!16018",
+    "full": "ghc/ghc!16018"
+  },
+  "web_url": "https://gitlab.haskell.org/ghc/ghc/-/merge_requests/16018",
+  "time_stats": {
+    "time_estimate": 0,
+    "total_time_spent": 0,
+    "human_time_estimate": null,
+    "human_total_time_spent": null
+  },
+  "squash": false,
+  "squash_on_merge": false,
+  "task_completion_status": {
+    "count": 0,
+    "completed_count": 0
+  },
+  "has_conflicts": false,
+  "blocking_discussions_resolved": true,
+  "approvals_before_merge": null,
+  "subscribed": false,
+  "changes_count": "2",
+  "latest_build_started_at": null,
+  "latest_build_finished_at": null,
+  "first_deployed_to_production_at": null,
+  "pipeline": null,
+  "head_pipeline": null,
+  "diff_refs": {
+    "base_sha": "1e60023bfac04260fa6f22a9a9bfb0774fb3ee4c",
+    "head_sha": "8cfc3a9241d9a178437ea10804384cd7125cd4e9",
+    "start_sha": "1e60023bfac04260fa6f22a9a9bfb0774fb3ee4c"
+  },
+  "merge_error": null,
+  "first_contribution": true,
+  "user": {
+    "can_merge": false
+  }
+}
diff --git a/gitlab-haskell.cabal b/gitlab-haskell.cabal
--- a/gitlab-haskell.cabal
+++ b/gitlab-haskell.cabal
@@ -1,7 +1,7 @@
 cabal-version: 3.0
 name:           gitlab-haskell
 category:       Git
-version:        1.4.1.0
+version:        1.5.0.0
 synopsis:       A Haskell library for the GitLab web API
 description:
             This library lifts the GitLab REST API into Haskell: <https://docs.gitlab.com/ee/api/>
@@ -155,6 +155,7 @@
   , data/api/merge-requests/time-estimate-merge-request.json
   , data/api/merge-requests/list-merge-request-pipelines.json
   , data/api/merge-requests/single-merge-request.json
+  , data/api/merge-requests/single-merge-request2.json
   , data/api/merge-requests/merge-to-default-merge-path.json
   , data/api/merge-requests/single-merge-request-diff-version.json
   , data/api/merge-requests/comments-on-merge-requests.json
@@ -195,6 +196,9 @@
                 , GitLab.SystemHooks.Rules
   other-modules:
                   GitLab.WebRequests.GitLabWebCalls
+                  Paths_gitlab_haskell
+  autogen-modules:
+                  Paths_gitlab_haskell
   hs-source-dirs:
                  src
   build-depends:
@@ -212,6 +216,8 @@
               , unix-compat
               , mtl >= 2.2.2
               , data-default
+              , safe-exceptions
+              , exceptions
   default-language: Haskell2010
   ghc-options: -Wall
                -- the following two for the stan static analysis tool
diff --git a/src/GitLab.hs b/src/GitLab.hs
--- a/src/GitLab.hs
+++ b/src/GitLab.hs
@@ -142,5 +142,14 @@
 runGitLabDbg (GitLabT action) = do
   liftIO $ hSetBuffering stdout LineBuffering
   manager <- liftIO $ newManager (mkManagerSettings def Nothing)
-  let cfg = GitLabServerConfig {url = "", authMethod = AuthMethodToken "", retries = 1, delayBetweenRetries = 1, debugSystemHooks = Nothing}
+  let
+    cfg =
+      GitLabServerConfig
+        { url = ""
+        , authMethod = AuthMethodToken ""
+        , retries = 1
+        , delayBetweenRetries = 1
+        , debugSystemHooks = Nothing
+        , userAgent = ""
+        }
   runExceptT (runReaderT action (GitLabState cfg manager))
diff --git a/src/GitLab/API/Boards.hs b/src/GitLab/API/Boards.hs
--- a/src/GitLab/API/Boards.hs
+++ b/src/GitLab/API/Boards.hs
@@ -45,9 +45,9 @@
   )
 where
 
+import Control.Monad.Except
 import qualified Data.ByteString.Lazy as BSL
 import Data.Default
-import Data.Either
 import Data.Maybe
 import Data.Text (Text)
 import qualified Data.Text as T
@@ -63,8 +63,9 @@
   GitLab [IssueBoard]
 projectIssueBoards project = do
   result <- projectIssueBoards' (project_id project)
-  -- return an empty list if the repository could not be found.
-  return (fromRight [] result)
+  case result of
+    Left resp -> throwError (httpResponseError "projectIssueBoards" resp)
+    Right xs -> return xs
 
 -- | returns all issue boards for a project given its project ID.
 projectIssueBoards' ::
@@ -111,7 +112,9 @@
   GitLab (Maybe IssueBoard)
 createIssueBoard project boardName = do
   result <- createIssueBoard' (project_id project) boardName
-  return (fromRight Nothing result)
+  case result of
+    Left resp -> throwError (httpResponseError "createIssueBoard" resp)
+    Right xs -> return xs
 
 -- | Creates a project issue board.
 createIssueBoard' ::
@@ -182,8 +185,9 @@
   GitLab [BoardIssue]
 projectBoardLists project board = do
   result <- projectBoardLists' (project_id project) (board_id board)
-  -- return an empty list if the repository could not be found.
-  return (fromRight [] result)
+  case result of
+    Left resp -> throwError (httpResponseError "projectBoardLists" resp)
+    Right xs -> return xs
 
 -- | Get a list of the board’s lists. Does not include open and closed lists.
 projectBoardLists' ::
@@ -207,11 +211,9 @@
   IssueBoard ->
   -- | list ID
   Int ->
-  GitLab (Maybe BoardIssue)
+  GitLab (Either (Response BSL.ByteString) (Maybe BoardIssue))
 boardList project board listId = do
-  result <- boardList' (project_id project) (board_id board) listId
-  -- return an empty list if the repository could not be found.
-  return (fromRight Nothing result)
+  boardList' (project_id project) (board_id board) listId
 
 -- | Get a single board list. Does not include open and closed lists.
 boardList' ::
@@ -240,8 +242,9 @@
   GitLab (Maybe BoardIssue)
 createBoardList project board attrs = do
   result <- createBoardList' (project_id project) (board_id board) attrs
-  -- return an empty list if the repository could not be found.
-  return (fromRight Nothing result)
+  case result of
+    Left resp -> throwError (httpResponseError "createBoardList" resp)
+    Right xs -> return xs
 
 -- | Creates a new issue board list.
 createBoardList' ::
diff --git a/src/GitLab/API/Branches.hs b/src/GitLab/API/Branches.hs
--- a/src/GitLab/API/Branches.hs
+++ b/src/GitLab/API/Branches.hs
@@ -27,7 +27,6 @@
 
 import Control.Monad.Except
 import qualified Data.ByteString.Lazy as BSL
-import Data.Either
 import Data.Text (Text)
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
@@ -106,8 +105,9 @@
   GitLab (Maybe Branch)
 createRepositoryBranch project branchName branchFrom = do
   result <- createRepositoryBranch' (project_id project) branchName branchFrom
-  -- return an empty list if the repository could not be found.
-  return (fromRight Nothing result)
+  case result of
+    Left resp -> throwError (httpResponseError "createRepositoryBranch" resp)
+    Right br -> return br
 
 -- | Create a new branch in the repository.
 createRepositoryBranch' ::
diff --git a/src/GitLab/API/Commits.hs b/src/GitLab/API/Commits.hs
--- a/src/GitLab/API/Commits.hs
+++ b/src/GitLab/API/Commits.hs
@@ -59,7 +59,6 @@
 
 import Control.Monad.Except
 import qualified Data.ByteString.Lazy as BSL
-import Data.Either
 import Data.Text (Text)
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
@@ -75,7 +74,9 @@
 repoCommits prj = do
   -- return an empty list if the repository could not be found.
   result <- gitlabGetMany (commitsAddr (project_id prj)) [("with_stats", Just "true")]
-  return (fromRight [] result)
+  case result of
+    Left resp -> throwError (httpResponseError "repoCommits" resp)
+    Right xs -> return xs
   where
     commitsAddr :: Int -> Text
     commitsAddr projId =
@@ -189,7 +190,9 @@
   GitLab (Maybe Commit)
 singleCommit project theHash = do
   result <- gitlabGetOne (commitsAddr (project_id project)) []
-  return (fromRight Nothing result)
+  case result of
+    Left resp -> throwError (httpResponseError "singleCommit" resp)
+    Right c -> return c
   where
     commitsAddr :: Int -> Text
     commitsAddr projId =
@@ -216,7 +219,7 @@
       [ ("branch", Just (T.encodeUtf8 branchName))
       ]
   case result of
-    Left _ -> return Nothing
+    Left resp -> throwError (httpResponseError "cherryPickCommit" resp)
     Right x -> return x
   where
     commitsAddr :: Text
@@ -244,7 +247,7 @@
       [ ("branch", Just (T.encodeUtf8 branchName))
       ]
   case result of
-    Left _ -> return Nothing
+    Left resp -> throwError (httpResponseError "revertCommit" resp)
     Right x -> return x
   where
     commitsAddr :: Text
diff --git a/src/GitLab/API/Pipelines.hs b/src/GitLab/API/Pipelines.hs
--- a/src/GitLab/API/Pipelines.hs
+++ b/src/GitLab/API/Pipelines.hs
@@ -37,6 +37,7 @@
   )
 where
 
+import Control.Monad.Except
 import qualified Data.ByteString.Lazy as BSL
 import Data.Default
 import Data.Maybe
@@ -60,8 +61,8 @@
 pipelines p attrs = do
   result <- pipelines' (project_id p) attrs
   case result of
+    Left resp -> throwError (httpResponseError "pipelines" resp)
     Right ps -> return (Just ps)
-    Left _err -> return Nothing -- perhaps throwError (GitLabError ..)
 
 -- | returns the pipelines for a project given its project ID.
 pipelines' ::
diff --git a/src/GitLab/API/Users.hs b/src/GitLab/API/Users.hs
--- a/src/GitLab/API/Users.hs
+++ b/src/GitLab/API/Users.hs
@@ -649,6 +649,6 @@
       params = [("username", Just (T.encodeUtf8 username))]
   result <- gitlabGetMany pathUser params
   case result of
-    Left _err -> return Nothing
+    Left resp -> throwError (httpResponseError "searchUser" resp)
     Right [] -> return Nothing
     Right (x : _) -> return (Just x)
diff --git a/src/GitLab/Types.hs b/src/GitLab/Types.hs
--- a/src/GitLab/Types.hs
+++ b/src/GitLab/Types.hs
@@ -112,6 +112,7 @@
   )
 where
 
+import Control.Monad.Catch (MonadCatch, MonadThrow)
 import Control.Monad.Except
 import Control.Monad.IO.Class
 import qualified Control.Monad.IO.Class as MIO
@@ -124,9 +125,11 @@
 import Data.Text (Text)
 import qualified Data.Text as T
 import Data.Time.Clock
+import Data.Version (showVersion)
 import Network.HTTP.Conduit
 import Network.HTTP.Types.Header (ResponseHeaders)
 import Network.HTTP.Types.Status (Status)
+import Paths_gitlab_haskell (version)
 
 -- | The monad in which the GitLab operations can be run.
 -- Contains the 'GitLabState' to run the requests with.
@@ -141,9 +144,15 @@
 instance (MIO.MonadIO m) => MIO.MonadIO (GitLabT m) where
   liftIO = GitLabT . MIO.liftIO
 
+deriving instance (MonadThrow m) => MonadThrow (GitLabT m)
+
+deriving instance (MonadCatch m) => MonadCatch (GitLabT m)
+
 data GitLabError
   = -- | A general error, e.g. a JSON parsing failure.
     GitLabError Text
+  | -- | A repeated HTTP attempt has exhausted the maximum retries
+    GitLabMaxRetriesError HttpException
   | -- | A non-success HTTP response from the GitLab server, including response
     -- headers.
     GitLabHttpError HttpResponseError
@@ -178,7 +187,9 @@
     -- | delay between HTTP request retries in seconds
     delayBetweenRetries :: Int,
     -- | write system hook events to files in the system temporary directory.
-    debugSystemHooks :: Maybe DebugSystemHooks
+    debugSystemHooks :: Maybe DebugSystemHooks,
+    -- | The user-agent string
+    userAgent :: Text
   }
 
 data DebugSystemHooks
@@ -192,7 +203,15 @@
 
 -- | default settings are https://gitlab.com with 'AuthMethodNone', the 'url' and 'authMethod' values may need to be overwritten.
 instance Default GitLabServerConfig where
-  def = GitLabServerConfig {url = "https://gitlab.com", authMethod = AuthMethodNone, retries = 5, delayBetweenRetries = 1, debugSystemHooks = Nothing}
+  def =
+      GitLabServerConfig
+        { url = "https://gitlab.com"
+        , authMethod = AuthMethodNone
+        , retries = 5
+        , delayBetweenRetries = 1
+        , debugSystemHooks = Nothing
+        , userAgent = T.pack ("gitlab-haskell/" <> showVersion version)
+        }
 
 -- | personal access token, see <https://docs.gitlab.com/ee/user/profile/personal_access_tokens.html>
 data AuthMethod
diff --git a/src/GitLab/WebRequests/GitLabWebCalls.hs b/src/GitLab/WebRequests/GitLabWebCalls.hs
--- a/src/GitLab/WebRequests/GitLabWebCalls.hs
+++ b/src/GitLab/WebRequests/GitLabWebCalls.hs
@@ -18,13 +18,14 @@
 
 import Control.Concurrent (threadDelay)
 import qualified Control.Exception as Exception
+import Control.Exception.Safe (try)
 import Control.Monad.Except
 import Control.Monad.IO.Class
 import qualified Control.Monad.Reader as MR
 import Data.Aeson
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Lazy as BSL
-import Data.Maybe (isJust)
+import Data.Maybe
 import Data.Text (Text)
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
@@ -209,12 +210,22 @@
           { method = httpMethod,
             requestHeaders =
               authHeaders
-                <> [ ("content-type", contentType)
+                <> [ ("content-type", contentType) ]
+                <> [ ("User-Agent", T.encodeUtf8 agentString)
+                   | let agentString = userAgent cfg
+                   , not $ T.null agentString
                    ],
             requestBody = RequestBodyBS (renderQuery False contentParams)
           }
-  liftIO $ tryGitLab 0 request (retries cfg) (delayBetweenRetries cfg) manager Nothing
+  tryGitLab 0 request (retries cfg) (delayBetweenRetries cfg) manager Nothing
 
+-- Tricky corner, when to return "Nothing"?
+-- Currently if:
+
+-- * explicit 204
+
+-- * 2xx code with no response body
+
 gitlabHTTPOne ::
   (FromJSON a) =>
   -- | HTTP method (PUT, POST, DELETE, GET)
@@ -238,7 +249,15 @@
       urlParams
       contentParams
   if successStatus (responseStatus response)
-    then return (Right (parseOne (responseBody response)))
+    then
+      let code = responseStatus response
+       in if code == status204
+            || code >= status200 && code < status300 && BSL.null (responseBody response) -- Deliberately nothing
+            -- Success status with no body
+            then pure $ Right Nothing
+            else pure $ case eitherDecode (responseBody response) of
+              Left _ -> Left response
+              Right r -> Right r
     else return (Left response)
 
 gitlabHTTPMany ::
@@ -268,27 +287,32 @@
           (urlParams <> [("per_page", Just "100"), ("page", Just (T.encodeUtf8 (T.pack (show pageNum))))])
           contentParams
       if successStatus (responseStatus response)
-        then do
-          case eitherDecode (responseBody response) of
-            Left decodeErr -> do
-              liftIO $
-                hPutStrLn stderr $
-                  "[gitlab-haskell] JSON decode error for "
-                    <> T.unpack urlPath
-                    <> " (page "
-                    <> show pageNum
-                    <> "): "
-                    <> decodeErr
-              liftIO $
-                hPutStrLn stderr $
-                  "[gitlab-haskell] Raw response body: "
-                    <> show (BSL.take 2000 (responseBody response))
-              return (Right accum)
-            Right moreResults -> do
-              let accum' = accum <> moreResults
-              if hasNextPage response
-                then go (pageNum + 1) accum'
-                else return (Right accum')
+        then
+          let code = responseStatus response
+           in if code == status204
+                || code >= status200 && code < status300 && BSL.null (responseBody response) -- Deliberately nothing
+                -- Success status with no body
+                then pure $ Right []
+                else case eitherDecode (responseBody response) of
+                  Left decodeErr -> do
+                    liftIO $
+                      hPutStrLn stderr $
+                        "[gitlab-haskell] JSON decode error for "
+                          <> T.unpack urlPath
+                          <> " (page "
+                          <> show pageNum
+                          <> "): "
+                          <> decodeErr
+                    liftIO $
+                      hPutStrLn stderr $
+                        "[gitlab-haskell] Raw response body: "
+                          <> show (BSL.take 2000 (responseBody response))
+                    return (Left response)
+                  Right moreResults -> do
+                    let accum' = accum <> moreResults
+                    if hasNextPage response
+                      then go (pageNum + 1) accum'
+                      else return (Right accum')
         else return (Left response)
 
 hasNextPage :: Response a -> Bool
@@ -319,15 +343,13 @@
   Manager ->
   -- | the exception to report if maximum retries met
   Maybe HttpException ->
-  IO (Response BSL.ByteString)
+  GitLab (Response BSL.ByteString)
 tryGitLab i request maxRetries delaySeconds manager lastException
-  | i == maxRetries = error (show lastException)
-  | otherwise =
-      httpLbs request manager
-        `Exception.catch` \ex -> threadDelay delaySeconds >> tryGitLab (i + 1) request maxRetries delaySeconds manager (Just ex)
-
-parseOne :: (FromJSON a) => BSL.ByteString -> Maybe a
-parseOne bs =
-  case eitherDecode bs of
-    Left _err -> Nothing
-    Right x -> Just x
+  | i == maxRetries + 1 = throwError (GitLabMaxRetriesError (fromJust lastException))
+  | otherwise = do
+      tried <- try $ httpLbs request manager
+      case tried of
+        Left ex -> do
+          liftIO (threadDelay delaySeconds)
+          tryGitLab (i + 1) request maxRetries delaySeconds manager (Just ex)
+        Right theResp -> return theResp