diff --git a/baikai-claude.cabal b/baikai-claude.cabal
--- a/baikai-claude.cabal
+++ b/baikai-claude.cabal
@@ -1,6 +1,6 @@
 cabal-version: 3.4
 name:          baikai-claude
-version:       0.3.0.1
+version:       0.3.0.2
 synopsis:      Anthropic Claude providers for the baikai abstraction
 description:
   Wraps the claude Haskell package as a Baikai Provider for both the Anthropic API and the
@@ -43,7 +43,7 @@
 
   build-depends:
     , aeson              ^>=2.2
-    , baikai             ^>=0.3.0
+    , baikai             ^>=0.4.0
     , base               >=4.20   && <5
     , base64-bytestring  ^>=1.2
     , bytestring         ^>=0.12
@@ -80,7 +80,7 @@
   ghc-options:    -threaded -with-rtsopts=-N
   build-depends:
     , aeson
-    , baikai            ^>=0.3.0
+    , baikai            ^>=0.4.0
     , baikai-claude
     , base              >=4.20   && <5
     , bytestring
diff --git a/src/Baikai/Provider/Claude/Interactive.hs b/src/Baikai/Provider/Claude/Interactive.hs
--- a/src/Baikai/Provider/Claude/Interactive.hs
+++ b/src/Baikai/Provider/Claude/Interactive.hs
@@ -23,6 +23,7 @@
     interactiveLaunchResult,
   )
 import Baikai.Prelude
+import Baikai.ThinkingLevel (ThinkingLevel (..), renderThinkingLevel)
 import Cradle (addArgs, cmd, run, setWorkingDir)
 import Data.Generics.Labels ()
 import Data.Text qualified as Text
@@ -50,6 +51,7 @@
 claudeInteractiveCommand cfg req =
   ( cfg ^. #executable,
     modelArgs req
+      <> effortArgs req
       <> systemPromptArgs req
       <> extraDirArgs req
       <> safetyArgs req
@@ -76,6 +78,17 @@
   Nothing -> []
   Just "" -> []
   Just mid -> ["--model", Text.unpack mid]
+
+-- | Claude's @--effort@ accepts @low|medium|high|xhigh|max@, but
+-- not @minimal@, so the lowest Baikai level maps up to @low@.
+effortArgs :: InteractiveLaunchRequest -> [String]
+effortArgs req = case req ^. #effort of
+  Nothing -> []
+  Just lvl -> ["--effort", Text.unpack (claudeEffortValue lvl)]
+
+claudeEffortValue :: ThinkingLevel -> Text
+claudeEffortValue ThinkingMinimal = "low"
+claudeEffortValue lvl = renderThinkingLevel lvl
 
 systemPromptArgs :: InteractiveLaunchRequest -> [String]
 systemPromptArgs req = case Text.strip <$> req ^. #systemPrompt of
diff --git a/src/Baikai/Provider/Claude/Internal/Request.hs b/src/Baikai/Provider/Claude/Internal/Request.hs
--- a/src/Baikai/Provider/Claude/Internal/Request.hs
+++ b/src/Baikai/Provider/Claude/Internal/Request.hs
@@ -184,6 +184,8 @@
   ThinkingLow -> Just "low"
   ThinkingMedium -> Just "medium"
   ThinkingHigh -> Nothing
+  ThinkingXHigh -> Just "xhigh"
+  ThinkingMax -> Just "max"
 
 -- | Map a baikai 'Tool.Tool' into the upstream Anthropic
 -- 'ClaudeTool.ToolDefinition'. The SDK helper is used to populate
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -32,6 +32,7 @@
     testGroup
       "Baikai.Provider.Claude"
       [ commandRenderingTest,
+        effortRenderingTests,
         batchCommandRenderingTest,
         stderrFloodTest,
         compatDetectionTest,
@@ -137,6 +138,24 @@
               "inspect the repo"
             ]
           )
+
+effortRenderingTests :: TestTree
+effortRenderingTests =
+  testGroup
+    "renders interactive reasoning effort"
+    [ testCase name $ do
+        let req = interactiveLaunchRequest "prompt" & #effort .~ Just level
+        claudeInteractiveCommand defaultClaudeInteractiveConfig req
+          @?= ("claude", ["--effort", expected, "--", "prompt"])
+    | (name, level, expected) <-
+        [ ("minimal as low", ThinkingMinimal, "low"),
+          ("low", ThinkingLow, "low"),
+          ("medium", ThinkingMedium, "medium"),
+          ("high", ThinkingHigh, "high"),
+          ("xhigh", ThinkingXHigh, "xhigh"),
+          ("max", ThinkingMax, "max")
+        ]
+    ]
 
 batchCommandRenderingTest :: TestTree
 batchCommandRenderingTest =
diff --git a/test/ThinkingSpec.hs b/test/ThinkingSpec.hs
--- a/test/ThinkingSpec.hs
+++ b/test/ThinkingSpec.hs
@@ -23,6 +23,8 @@
   testGroup
     "ThinkingSpec"
     [ testGroup "mapRequest max_tokens" (neverExceedsCapTests <> styleTests),
+      adaptiveHigherEffortTests,
+      maxBudgetTest,
       explicitMaxTokensTest,
       handRolledUnclampedTest,
       tooSmallCapDropsThinkingTest,
@@ -48,7 +50,9 @@
   [ ("minimal", ThinkingMinimal),
     ("low", ThinkingLow),
     ("medium", ThinkingMedium),
-    ("high", ThinkingHigh)
+    ("high", ThinkingHigh),
+    ("xhigh", ThinkingXHigh),
+    ("max", ThinkingMax)
   ]
 
 neverExceedsCapTests :: [TestTree]
@@ -82,6 +86,36 @@
     (levelName, level) <- thinkingLevels
   ]
 
+adaptiveHigherEffortTests :: TestTree
+adaptiveHigherEffortTests =
+  testGroup
+    "adaptive higher effort"
+    [ testCase name $ do
+        req <-
+          requestFor
+            anthropic_claude_opus_4_7
+            (emptyOptions & #thinking .~ Just level)
+        requestThinking req @?= Just Messages.ThinkingAdaptive
+        (Messages.output_config req >>= Messages.effort) @?= Just expected
+    | (name, level, expected) <-
+        [ ("xhigh is preserved", ThinkingXHigh, "xhigh"),
+          ("max is preserved", ThinkingMax, "max")
+        ]
+    ]
+
+maxBudgetTest :: TestTree
+maxBudgetTest =
+  testCase "manual max effort uses 32768 tokens with visible-output room" $ do
+    req <-
+      requestFor
+        anthropic_claude_haiku_4_5
+        (emptyOptions & #thinking .~ Just ThinkingMax)
+    requestThinking req
+      @?= Just Messages.ThinkingEnabled {Messages.budget_tokens = 32768}
+    assertBool
+      "max_tokens leaves visible-output room beyond the max thinking budget"
+      (Messages.max_tokens req > 32768)
+
 explicitMaxTokensTest :: TestTree
 explicitMaxTokensTest =
   testCase "explicit maxTokens participates as visible output plus budget, then clamps" $ do
@@ -167,6 +201,8 @@
   ThinkingLow -> Just "low"
   ThinkingMedium -> Just "medium"
   ThinkingHigh -> Nothing
+  ThinkingXHigh -> Just "xhigh"
+  ThinkingMax -> Just "max"
 
 streamFidelityTests :: TestTree
 streamFidelityTests =