From 7c154c6659ea876b8dfcbfb3e96ce5095cef365c Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Sat, 11 Apr 2026 13:06:24 +0900
Subject: [PATCH] fix(anthropic-effort): skip effort injection for Haiku models
 (#3308)

Haiku models do not support the effort parameter and return API errors
when it is passed. The hook now explicitly checks for Haiku model
patterns and skips effort injection, preventing silent title generation
failures.

Added EFFORT_UNSUPPORTED_PATTERN and isEffortUnsupportedModel() to
detect and skip Haiku models.

Fixes #3308
---
 src/hooks/anthropic-effort/hook.ts       |  7 +++++++
 src/hooks/anthropic-effort/index.test.ts | 24 ++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/hooks/anthropic-effort/hook.ts b/src/hooks/anthropic-effort/hook.ts
index 76fba5245..fb5a9a209 100644
--- a/src/hooks/anthropic-effort/hook.ts
+++ b/src/hooks/anthropic-effort/hook.ts
@@ -1,6 +1,7 @@
 import { log, normalizeModelID } from "../../shared"
 
 const OPUS_PATTERN = /claude-.*opus/i
+const EFFORT_UNSUPPORTED_PATTERN = /claude-.*haiku/i
 const INTERNAL_SKIP_AGENTS = new Set(["title", "summary", "compaction"])
 
 function isClaudeProvider(providerID: string, modelID: string): boolean {
@@ -14,6 +15,11 @@ function isOpusModel(modelID: string): boolean {
   return OPUS_PATTERN.test(normalized)
 }
 
+function isEffortUnsupportedModel(modelID: string): boolean {
+  const normalized = normalizeModelID(modelID)
+  return EFFORT_UNSUPPORTED_PATTERN.test(normalized)
+}
+
 function shouldSkipForInternalAgent(agentName: string | undefined): boolean {
   if (!agentName) return false
   return INTERNAL_SKIP_AGENTS.has(agentName.trim().toLowerCase())
@@ -60,6 +66,7 @@ export function createAnthropicEffortHook() {
       if (!isClaudeProvider(model.providerID, model.modelID)) return
       if (shouldSkipForInternalAgent(agent?.name)) return
       if (output.options.effort !== undefined) return
+      if (isEffortUnsupportedModel(model.modelID)) return
 
       const opus = isOpusModel(model.modelID)
       const clamped = clampVariant(message.variant, opus)
diff --git a/src/hooks/anthropic-effort/index.test.ts b/src/hooks/anthropic-effort/index.test.ts
index 056ff0a28..5ca923cd2 100644
--- a/src/hooks/anthropic-effort/index.test.ts
+++ b/src/hooks/anthropic-effort/index.test.ts
@@ -147,6 +147,30 @@ describe("createAnthropicEffortHook", () => {
 
       expect(output.options.effort).toBeUndefined()
     })
+
+    describe("#given haiku models (effort unsupported)", () => {
+      const haikuModels = [
+        "claude-haiku-4-5",
+        "claude-haiku-4.6",
+        "claude-haiku",
+        "claude-haiku-20240307",
+      ]
+
+      for (const modelID of haikuModels) {
+        it(`skips effort injection for ${modelID}`, async () => {
+          // given
+          const hook = createAnthropicEffortHook()
+          const { input, output } = createMockParams({ modelID })
+
+          // when
+          await hook["chat.params"](input, output)
+
+          // then
+          expect(output.options.effort).toBeUndefined()
+          expect(input.message.variant).toBe("max")
+        })
+      }
+    })
   })
 
   describe("existing options", () => {