diff --git a/src/agents/pi-embedded-runner/replay-history.ts b/src/agents/pi-embedded-runner/replay-history.ts
index 92c540141407..53aa90dede0c 100644
--- a/src/agents/pi-embedded-runner/replay-history.ts
+++ b/src/agents/pi-embedded-runner/replay-history.ts
@@ -35,6 +35,7 @@ import { STREAM_ERROR_FALLBACK_TEXT } from "../stream-message-shared.js";
 import { sanitizeToolCallIdsForCloudCodeAssist } from "../tool-call-id.js";
 import type { TranscriptPolicy } from "../transcript-policy.js";
 import {
+  providerRequiresSignedThinking,
   resolveTranscriptPolicy,
   shouldAllowProviderOwnedThinkingReplay,
 } from "../transcript-policy.js";
@@ -658,12 +659,6 @@ function isSameModelSnapshot(a: ModelSnapshotEntry, b: ModelSnapshotEntry): bool
   );
 }
 
-const SIGNED_THINKING_PROVIDERS = new Set(["anthropic", "amazon-bedrock", "anthropic-vertex"]);
-
-function providerRequiresSignedThinking(provider?: string | null): boolean {
-  return SIGNED_THINKING_PROVIDERS.has(provider ?? "");
-}
-
 /**
  * Applies the generic replay-history cleanup pipeline before provider-owned
  * replay hooks run.
@@ -697,12 +692,11 @@ export async function sanitizeSessionHistory(params: {
     });
   const withInterSessionMarkers = annotateInterSessionUserMessages(params.messages);
   const signedThinkingProvider = providerRequiresSignedThinking(params.provider);
-  const allowProviderOwnedThinkingReplay =
-    shouldAllowProviderOwnedThinkingReplay({
-      modelApi: params.modelApi,
-      policy,
-    }) ||
-    (signedThinkingProvider && !policy.dropThinkingBlocks);
+  const allowProviderOwnedThinkingReplay = shouldAllowProviderOwnedThinkingReplay({
+    modelApi: params.modelApi,
+    provider: params.provider,
+    policy,
+  });
   const isOpenAIResponsesApi =
     params.modelApi === "openai-responses" ||
     params.modelApi === "openai-codex-responses" ||
diff --git a/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.test.ts b/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.test.ts
index 00d894a42a1e..e5839dd86a50 100644
--- a/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.test.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.test.ts
@@ -130,6 +130,46 @@ describe("sanitizeReplayToolCallIdsForStream", () => {
     });
   });
 
+  it("preserves signed-thinking replay ids when requested by provider policy", () => {
+    const rawId = "call_1";
+    const out = sanitizeReplayToolCallIdsForStream({
+      messages: [
+        {
+          role: "assistant",
+          content: [
+            { type: "thinking", thinking: "internal", thinkingSignature: "sig_1" },
+            { type: "toolUse", id: rawId, name: "read", input: { path: "." } },
+          ],
+        } as never,
+        {
+          role: "toolResult",
+          toolCallId: rawId,
+          toolUseId: rawId,
+          toolName: "read",
+          content: [{ type: "text", text: "ok" }],
+          isError: false,
+        } as never,
+      ],
+      mode: "strict",
+      preserveReplaySafeThinkingToolCallIds: true,
+      repairToolUseResultPairing: true,
+    });
+
+    expect(out.map((message) => message.role)).toEqual(["assistant", "toolResult"]);
+    expect(requireAssistantMessage(out[0]).content[1]).toMatchObject({
+      type: "toolUse",
+      id: "call_1",
+      name: "read",
+    });
+    expect(toolResultSummary(out[1])).toEqual({
+      role: "toolResult",
+      toolCallId: "call_1",
+      toolUseId: "call_1",
+      toolName: "read",
+      isError: false,
+    });
+  });
+
   it("synthesizes missing tool results after strict id sanitization", () => {
     const rawId = "call_function_av7cbkigmk7x1";
     const out = sanitizeReplayToolCallIdsForStream({
diff --git a/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.ts b/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.ts
index 6977205379da..ef9432b02cc4 100644
--- a/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.tool-call-normalization.ts
@@ -919,6 +919,7 @@ export function wrapStreamFnSanitizeMalformedToolCalls(
     TranscriptPolicy,
     "validateGeminiTurns" | "validateAnthropicTurns" | "preserveSignatures" | "dropThinkingBlocks"
   >,
+  provider?: string | null,
 ): StreamFn {
   return (model, context, options) => {
     const ctx = context as unknown as { messages?: unknown };
@@ -928,6 +929,7 @@ export function wrapStreamFnSanitizeMalformedToolCalls(
     }
     const allowProviderOwnedThinkingReplay = shouldAllowProviderOwnedThinkingReplay({
       modelApi: (model as { api?: unknown })?.api as string | null | undefined,
+      provider,
       policy: {
         validateAnthropicTurns: transcriptPolicy?.validateAnthropicTurns === true,
         preserveSignatures: transcriptPolicy?.preserveSignatures === true,
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index 1262c0701a66..a3bb3a88d03e 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -2855,6 +2855,7 @@ export async function runEmbeddedAttempt(
             preserveNativeAnthropicToolUseIds: transcriptPolicy.preserveNativeAnthropicToolUseIds,
             preserveReplaySafeThinkingToolCallIds: shouldAllowProviderOwnedThinkingReplay({
               modelApi: (model as { api?: unknown })?.api as string | null | undefined,
+              provider: params.provider,
               policy: transcriptPolicy,
             }),
             repairToolUseResultPairing: transcriptPolicy.repairToolUseResultPairing,
@@ -2911,6 +2912,7 @@ export async function runEmbeddedAttempt(
         activeSession.agent.streamFn,
         allowedToolNames,
         transcriptPolicy,
+        params.provider,
       );
       activeSession.agent.streamFn = wrapStreamFnTrimToolCallNames(
         activeSession.agent.streamFn,
diff --git a/src/agents/transcript-policy.test.ts b/src/agents/transcript-policy.test.ts
index 402f6bc7aaa3..e8a3a5792976 100644
--- a/src/agents/transcript-policy.test.ts
+++ b/src/agents/transcript-policy.test.ts
@@ -617,6 +617,24 @@ describe("resolveTranscriptPolicy", () => {
     ).toBe(true);
   });
 
+  it.each(["anthropic", "amazon-bedrock"] as const)(
+    "allows provider-owned thinking replay for signed-thinking %s recovery policies",
+    (provider) => {
+      expect(
+        shouldAllowProviderOwnedThinkingReplay({
+          provider,
+          modelApi:
+            provider === "amazon-bedrock" ? "bedrock-converse-stream" : "anthropic-messages",
+          policy: {
+            validateAnthropicTurns: true,
+            preserveSignatures: false,
+            dropThinkingBlocks: false,
+          },
+        }),
+      ).toBe(true);
+    },
+  );
+
   it("does not allow immutable provider-owned thinking replay for github-copilot claude models", () => {
     const policy = resolveTranscriptPolicy({
       provider: "github-copilot",
diff --git a/src/agents/transcript-policy.ts b/src/agents/transcript-policy.ts
index a3b093d6d760..99d350a5f8a0 100644
--- a/src/agents/transcript-policy.ts
+++ b/src/agents/transcript-policy.ts
@@ -32,17 +32,26 @@ export type TranscriptPolicy = {
   allowSyntheticToolResults: boolean;
 };
 
+const SIGNED_THINKING_PROVIDERS = new Set(["anthropic", "amazon-bedrock", "anthropic-vertex"]);
+
+export function providerRequiresSignedThinking(provider?: string | null): boolean {
+  return SIGNED_THINKING_PROVIDERS.has(normalizeProviderId(provider ?? ""));
+}
+
 export function shouldAllowProviderOwnedThinkingReplay(params: {
   modelApi?: string | null;
+  provider?: string | null;
   policy: Pick<
     TranscriptPolicy,
     "validateAnthropicTurns" | "preserveSignatures" | "dropThinkingBlocks"
   >;
 }): boolean {
+  const hasProviderOwnedSignedThinking =
+    params.policy.preserveSignatures || providerRequiresSignedThinking(params.provider);
   return (
     isAnthropicApi(params.modelApi) &&
     params.policy.validateAnthropicTurns &&
-    params.policy.preserveSignatures &&
+    hasProviderOwnedSignedThinking &&
     !params.policy.dropThinkingBlocks
   );
 }