diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3187695341..7650a8c602 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1428,6 +1428,13 @@ As of 2026-10-21, the milestone includes **829 merged pull requests**.
   stalling other runs, requests and streams meanwhile. They now read the
   config once per call in a worker, as image search already did. ([#7580])
 
+- **wizard:** The setup wizard's Anthropic default model is now
+  `claude-sonnet-5-5` instead of the retired `claude-sonnet-4-20250514`, which
+  the Claude API no longer accepts. For that model the wizard leaves out the
+  extended-thinking (`budget_tokens`) and thinking-disabled templates it
+  rejects. The Anthropic examples in `config.example.yaml` and the
+  configuration docs follow the same model.([#7585])
+
 - **auth:** The public auth routes (`/register`, `/setup-status`,
   `/providers`, `/oauth/{provider}` and `/callback/{provider}`) no longer read
   `config.yaml` and `extensions_config.json` on the event loop. Each request
@@ -13177,5 +13184,6 @@ with **180 merged pull requests** since the first 2.0 milestone tag.
 [#7560]: https://github.com/bytedance/deer-flow/pull/7560
 [#7576]: https://github.com/bytedance/deer-flow/pull/7576
 [#7580]: https://github.com/bytedance/deer-flow/pull/7580
+[#7585]: https://github.com/bytedance/deer-flow/pull/7585
 [#7588]: https://github.com/bytedance/deer-flow/pull/7588
 [#7591]: https://github.com/bytedance/deer-flow/pull/7591
diff --git a/backend/tests/test_setup_wizard.py b/backend/tests/test_setup_wizard.py
index 84f6b8a473..4078b9faff 100644
--- a/backend/tests/test_setup_wizard.py
+++ b/backend/tests/test_setup_wizard.py
@@ -147,6 +147,20 @@ class TestProviders:
             # Override must not mutate the shared provider-level config.
             assert provider.extra_config["supports_vision"] is True
 
+    def test_anthropic_sonnet_5_5_omits_rejected_thinking_templates(self):
+        """Sonnet 5.5 rejects budget_tokens and thinking disabled; other Claude models keep them."""
+        providers = {provider.name: provider for provider in LLM_PROVIDERS}
+        anthropic = providers["anthropic"]
+        assert anthropic.default_model == "claude-sonnet-5-5"
+
+        config = anthropic.extra_config_for("claude-sonnet-5-5")
+        assert "when_thinking_enabled" not in config
+        assert "when_thinking_disabled" not in config
+
+        assert anthropic.extra_config_for("claude-sonnet-4-5")["when_thinking_enabled"]["thinking"]["budget_tokens"] == 4096
+        # Omission must not mutate the shared provider-level config.
+        assert "when_thinking_enabled" in anthropic.extra_config
+
     def test_extra_config_for_returns_provider_config_without_override(self):
         """Providers without per-model overrides return their config unchanged."""
         providers = {provider.name: provider for provider in LLM_PROVIDERS}
diff --git a/config.example.yaml b/config.example.yaml
index 84adfa82e0..b4d17baa84 100644
--- a/config.example.yaml
+++ b/config.example.yaml
@@ -396,29 +396,20 @@ models:
   # for example on Docker Desktop:
   #   base_url: http://host.docker.internal:8080/v1
 
-  # Example: Anthropic Claude model (with extended thinking)
-  # supports_thinking: true is required — without it, DeerFlow silently falls
-  # back to non-thinking mode even when the UI thinking toggle is on.
-  # budget_tokens is required by the Anthropic API when thinking.type=enabled
-  # (no server default; min 1024; must be less than max_tokens).
-  # - name: claude-sonnet-4
-  #   display_name: Claude Sonnet 4
+  # Example: Anthropic Claude model (thinks by default)
+  # Claude Sonnet 5.5 rejects extended thinking (budget_tokens), thinking
+  # type disabled, temperature, top_p and top_k, so leave them out.
+  # max_tokens covers both thinking and the answer.
+  # - name: claude-sonnet-5-5
+  #   display_name: Claude Sonnet 5.5
   #   use: langchain_anthropic:ChatAnthropic
-  #   model: claude-sonnet-4-20250514
+  #   model: claude-sonnet-5-5
   #   api_key: $ANTHROPIC_API_KEY
   #   default_request_timeout: 600.0
   #   max_retries: 2
-  #   max_tokens: 16000         # Per-call output cap
+  #   max_tokens: 16000         # Per-call output cap (thinking + answer)
   #   context_window: 200000    # Total prompt + completion capacity
   #   supports_vision: true
-  #   supports_thinking: true
-  #   when_thinking_enabled:
-  #     thinking:
-  #       type: enabled
-  #       budget_tokens: 4096   # required; min 1024; must be < max_tokens
-  #   when_thinking_disabled:
-  #     thinking:
-  #       type: disabled
 
   # Example: Google Gemini model (native SDK, no thinking support)
   # - name: gemini-2.5-pro
diff --git a/frontend/src/content/en/application/configuration.mdx b/frontend/src/content/en/application/configuration.mdx
index bf21424e55..43bf3ffd71 100644
--- a/frontend/src/content/en/application/configuration.mdx
+++ b/frontend/src/content/en/application/configuration.mdx
@@ -48,21 +48,14 @@ models:
   <Tabs.Tab>
 ```yaml
 models:
-  - name: claude-3-5-sonnet
+  - name: claude-sonnet-5-5
     use: langchain_anthropic:ChatAnthropic
-    model: claude-3-5-sonnet-20241022
+    model: claude-sonnet-5-5
     api_key: $ANTHROPIC_API_KEY
     default_request_timeout: 600.0
     max_retries: 2
     max_tokens: 8192
     supports_vision: true
-    supports_thinking: true
-    when_thinking_enabled:
-      thinking:
-        type: enabled
-    when_thinking_disabled:
-      thinking:
-        type: disabled
 ```
   </Tabs.Tab>
   <Tabs.Tab>
diff --git a/scripts/wizard/providers.py b/scripts/wizard/providers.py
index 968e072854..21d9f41d8e 100644
--- a/scripts/wizard/providers.py
+++ b/scripts/wizard/providers.py
@@ -23,6 +23,9 @@ class LLMProvider:
     # capability (e.g. MiniMax M3 supports vision but M2.7 is text-only). The
     # provider-level extra_config holds the default (default_model) capability.
     model_vision_overrides: dict[str, bool] = field(default_factory=dict)
+    # Per-model extra_config keys to leave out for models whose API rejects
+    # them (e.g. Claude Sonnet 5.5 rejects budget_tokens and thinking disabled).
+    model_omitted_config: dict[str, tuple[str, ...]] = field(default_factory=dict)
     auth_hint: str | None = None
     base_url_prompt: str | None = None
     model_prompt: str | None = None
@@ -38,6 +41,8 @@ class LLMProvider:
         config = dict(self.extra_config)
         if model_name in self.model_vision_overrides:
             config["supports_vision"] = self.model_vision_overrides[model_name]
+        for key in self.model_omitted_config.get(model_name, ()):
+            config.pop(key, None)
         return config
 
 
@@ -256,10 +261,10 @@ LLM_PROVIDERS: list[LLMProvider] = [
     LLMProvider(
         name="anthropic",
         display_name="Anthropic",
-        description="Claude Sonnet 4 with extended thinking",
+        description="Claude Sonnet 5.5 with thinking",
         use="langchain_anthropic:ChatAnthropic",
-        models=["claude-sonnet-4-20250514", "claude-opus-4-5", "claude-sonnet-4-5"],
-        default_model="claude-sonnet-4-20250514",
+        models=["claude-sonnet-5-5", "claude-opus-4-5", "claude-sonnet-4-5"],
+        default_model="claude-sonnet-5-5",
         env_var="ANTHROPIC_API_KEY",
         package="langchain-anthropic",
         extra_config={
@@ -269,6 +274,8 @@ LLM_PROVIDERS: list[LLMProvider] = [
             "supports_vision": True,
             **ANTHROPIC_THINKING_CONFIG,
         },
+        # Sonnet 5.5 thinks by default and rejects budget_tokens and thinking disabled.
+        model_omitted_config={"claude-sonnet-5-5": ("when_thinking_enabled", "when_thinking_disabled")},
     ),
     LLMProvider(
         name="deepseek",