diff --git a/.openclaw-sync/source.json b/.openclaw-sync/source.json
index 72d42a1fb..a8428d6e7 100644
--- a/.openclaw-sync/source.json
+++ b/.openclaw-sync/source.json
@@ -1,5 +1,5 @@
 {
   "repository": "openclaw/openclaw",
-  "sha": "b9fd13e8d7304fd5d35f93bee1dd460484fcc94d",
-  "syncedAt": "2026-04-27T20:25:13.492Z"
+  "sha": "599b1b84620bc9c43e37a385d6f5468289e5156e",
+  "syncedAt": "2026-04-27T20:38:02.043Z"
 }
diff --git a/docs/plugins/sdk-provider-plugins.md b/docs/plugins/sdk-provider-plugins.md
index ee2fa9f59..1efcdac36 100644
--- a/docs/plugins/sdk-provider-plugins.md
+++ b/docs/plugins/sdk-provider-plugins.md
@@ -340,7 +340,7 @@ API key auth, and dynamic model resolution.
       Each family builder is composed from lower-level public helpers exported from the same package, which you can reach for when a provider needs to go off the common pattern:
 
       - `openclaw/plugin-sdk/provider-model-shared` — `ProviderReplayFamily`, `buildProviderReplayFamilyHooks(...)`, and the raw replay builders (`buildOpenAICompatibleReplayPolicy`, `buildAnthropicReplayPolicyForModel`, `buildGoogleGeminiReplayPolicy`, `buildHybridAnthropicOrOpenAIReplayPolicy`). Also exports Gemini replay helpers (`sanitizeGoogleGeminiReplayHistory`, `resolveTaggedReasoningOutputMode`) and endpoint/model helpers (`resolveProviderEndpoint`, `normalizeProviderId`, `normalizeGooglePreviewModelId`, `normalizeNativeXaiModelId`).
-      - `openclaw/plugin-sdk/provider-stream` — `ProviderStreamFamily`, `buildProviderStreamFamilyHooks(...)`, `composeProviderStreamWrappers(...)`, plus the shared OpenAI/Codex wrappers (`createOpenAIAttributionHeadersWrapper`, `createOpenAIFastModeWrapper`, `createOpenAIServiceTierWrapper`, `createOpenAIResponsesContextManagementWrapper`, `createCodexNativeWebSearchWrapper`), DeepSeek V4 OpenAI-compatible wrapper (`createDeepSeekV4OpenAICompatibleThinkingWrapper`), and shared proxy/provider wrappers (`createOpenRouterWrapper`, `createToolStreamWrapper`, `createMinimaxFastModeWrapper`).
+      - `openclaw/plugin-sdk/provider-stream` — `ProviderStreamFamily`, `buildProviderStreamFamilyHooks(...)`, `composeProviderStreamWrappers(...)`, plus the shared OpenAI/Codex wrappers (`createOpenAIAttributionHeadersWrapper`, `createOpenAIFastModeWrapper`, `createOpenAIServiceTierWrapper`, `createOpenAIResponsesContextManagementWrapper`, `createCodexNativeWebSearchWrapper`), DeepSeek V4 OpenAI-compatible wrapper (`createDeepSeekV4OpenAICompatibleThinkingWrapper`), Anthropic Messages thinking prefill cleanup (`createAnthropicThinkingPrefillPayloadWrapper`), and shared proxy/provider wrappers (`createOpenRouterWrapper`, `createToolStreamWrapper`, `createMinimaxFastModeWrapper`).
       - `openclaw/plugin-sdk/provider-tools` — `ProviderToolCompatFamily`, `buildProviderToolCompatFamilyHooks("gemini")`, underlying Gemini schema helpers (`normalizeGeminiToolSchemas`, `inspectGeminiToolSchemas`), and xAI compat helpers (`resolveXaiModelCompatPatch()`, `applyXaiModelCompat(model)`). The bundled xAI plugin uses `normalizeResolvedModel` + `contributeResolvedModelCompat` with these to keep xAI rules owned by the provider.
 
       Some stream helpers stay provider-local on purpose. `@openclaw/anthropic-provider` keeps `wrapAnthropicProviderStream`, `resolveAnthropicBetas`, `resolveAnthropicFastMode`, `resolveAnthropicServiceTier`, and the lower-level Anthropic wrapper builders in its own public `api.ts` / `contract-api.ts` seam because they encode Claude OAuth beta handling and `context1m` gating. The xAI plugin similarly keeps native xAI Responses shaping in its own `wrapStreamFn` (`/fast` aliases, default `tool_stream`, unsupported strict-tool cleanup, xAI-specific reasoning-payload removal).
diff --git a/docs/providers/cloudflare-ai-gateway.md b/docs/providers/cloudflare-ai-gateway.md
index f9768c100..f0552e528 100644
--- a/docs/providers/cloudflare-ai-gateway.md
+++ b/docs/providers/cloudflare-ai-gateway.md
@@ -19,6 +19,11 @@ Cloudflare AI Gateway sits in front of provider APIs and lets you add analytics,
 For Anthropic models routed through Cloudflare AI Gateway, use your **Anthropic API key** as the provider key.
 </Note>
 
+When thinking is enabled for Anthropic Messages models, OpenClaw strips trailing
+assistant prefill turns before sending the payload through Cloudflare AI Gateway.
+Anthropic rejects response prefilling with extended thinking, while ordinary
+non-thinking prefill remains available.
+
 ## Getting started
 
 <Steps>
diff --git a/docs/reference/transcript-hygiene.md b/docs/reference/transcript-hygiene.md
index 6783d1e62..198167d3d 100644
--- a/docs/reference/transcript-hygiene.md
+++ b/docs/reference/transcript-hygiene.md
@@ -137,6 +137,8 @@ external end-user instructions.
 
 - Tool result pairing repair and synthetic tool results.
 - Turn validation (merge consecutive user turns to satisfy strict alternation).
+- Trailing assistant prefill turns are stripped from outgoing Anthropic Messages
+  payloads when thinking is enabled, including Cloudflare AI Gateway routes.
 - Thinking blocks with missing, empty, or blank replay signatures are stripped
   before provider conversion. If that empties an assistant turn, OpenClaw keeps
   turn shape with non-empty omitted-reasoning text.