diff --git a/src/acp/runtime/error-text.test.ts b/src/acp/runtime/error-text.test.ts
index 14f7ff91f55..80d3eea39e5 100644
--- a/src/acp/runtime/error-text.test.ts
+++ b/src/acp/runtime/error-text.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from "vitest";
-import { formatAcpRuntimeErrorText } from "./error-text.js";
-import { AcpRuntimeError } from "./errors.js";
+import { formatAcpRuntimeErrorText, toAcpRuntimeErrorText } from "./error-text.js";
+import { AcpRuntimeError, toAcpRuntimeError } from "./errors.js";
 
 describe("formatAcpRuntimeErrorText", () => {
   it("adds actionable next steps for known ACP runtime error codes", () => {
@@ -18,4 +18,49 @@ describe("formatAcpRuntimeErrorText", () => {
       "ACP error (ACP_TURN_FAILED): turn failed\nnext: Retry, or use `/acp cancel` and send the message again.",
     );
   });
+
+  it("surfaces redacted numeric RequestError details in runtime failure text", () => {
+    const token = "sk-abcdefghijklmnopqrstuvwxyz123456";
+    const requestError = Object.assign(new Error("Internal error"), {
+      name: "RequestError",
+      code: -32603,
+      data: {
+        details: `Unknown config option: timeout; token=${token}`,
+      },
+    });
+
+    const text = formatAcpRuntimeErrorText(
+      toAcpRuntimeError({
+        error: requestError,
+        fallbackCode: "ACP_TURN_FAILED",
+        fallbackMessage: "fallback",
+      }),
+    );
+
+    expect(text).toContain(
+      "ACP error (ACP_TURN_FAILED): Internal error: Unknown config option: timeout",
+    );
+    expect(text).toContain("next: Retry");
+    expect(text).not.toContain(token);
+  });
+
+  it("applies the same RequestError details normalization through text conversion", () => {
+    const requestError = Object.assign(new Error("Internal error"), {
+      name: "RequestError",
+      code: -32603,
+      data: {
+        details: "Unknown config option: timeout",
+      },
+    });
+
+    const text = toAcpRuntimeErrorText({
+      error: requestError,
+      fallbackCode: "ACP_TURN_FAILED",
+      fallbackMessage: "fallback",
+    });
+
+    expect(text).toContain(
+      "ACP error (ACP_TURN_FAILED): Internal error: Unknown config option: timeout",
+    );
+  });
 });
diff --git a/src/acp/runtime/errors.test.ts b/src/acp/runtime/errors.test.ts
index c05ccfb705a..e91a0d2bb3b 100644
--- a/src/acp/runtime/errors.test.ts
+++ b/src/acp/runtime/errors.test.ts
@@ -3,6 +3,7 @@ import {
   AcpRuntimeError,
   formatAcpErrorChain,
   isAcpRuntimeError,
+  toAcpRuntimeError,
   withAcpRuntimeErrorBoundary,
 } from "./errors.js";
 
@@ -72,6 +73,65 @@ describe("withAcpRuntimeErrorBoundary", () => {
     expect(error.cause).toBe(foreignError);
     expect(isAcpRuntimeError(foreignError)).toBe(true);
   });
+
+  it("preserves redacted RequestError details from numeric ACP errors", () => {
+    const token = "sk-abcdefghijklmnopqrstuvwxyz123456";
+    const requestError = Object.assign(new Error("Internal error"), {
+      name: "RequestError",
+      code: -32603,
+      data: {
+        details: `unknown config option: timeout; token=${token}`,
+      },
+    });
+
+    const error = toAcpRuntimeError({
+      error: requestError,
+      fallbackCode: "ACP_TURN_FAILED",
+      fallbackMessage: "fallback",
+    });
+
+    expect(error.code).toBe("ACP_TURN_FAILED");
+    expect(error.message).toContain("Internal error: unknown config option: timeout");
+    expect(error.message).not.toContain(token);
+    expect(error.cause).toBe(requestError);
+  });
+
+  it("keeps foreign OpenClaw ACP string code behavior unchanged", () => {
+    const foreignError = Object.assign(new Error("backend missing"), {
+      code: "ACP_BACKEND_MISSING",
+      data: {
+        details: "extra backend diagnostic",
+      },
+    });
+
+    const error = toAcpRuntimeError({
+      error: foreignError,
+      fallbackCode: "ACP_TURN_FAILED",
+      fallbackMessage: "fallback",
+    });
+
+    expect(error.code).toBe("ACP_BACKEND_MISSING");
+    expect(error.message).toBe("backend missing");
+    expect(error.cause).toBe(foreignError);
+  });
+
+  it("keeps generic non-RequestError messages unchanged", () => {
+    const sourceError = Object.assign(new Error("boom"), {
+      data: {
+        details: "extra diagnostic",
+      },
+    });
+
+    const error = toAcpRuntimeError({
+      error: sourceError,
+      fallbackCode: "ACP_TURN_FAILED",
+      fallbackMessage: "fallback",
+    });
+
+    expect(error.code).toBe("ACP_TURN_FAILED");
+    expect(error.message).toBe("boom");
+    expect(error.cause).toBe(sourceError);
+  });
 });
 
 describe("formatAcpErrorChain redaction", () => {
diff --git a/src/acp/runtime/errors.ts b/src/acp/runtime/errors.ts
index 2cfe3dbc4c8..d37e0991c75 100644
--- a/src/acp/runtime/errors.ts
+++ b/src/acp/runtime/errors.ts
@@ -43,6 +43,31 @@ function getForeignAcpRuntimeError(value: unknown): {
   };
 }
 
+function readAcpRequestErrorDetails(value: Error): string | undefined {
+  const code = (value as { code?: unknown }).code;
+  if (typeof code !== "number") {
+    return undefined;
+  }
+  const data = (value as { data?: unknown }).data;
+  if (!data || typeof data !== "object") {
+    return undefined;
+  }
+  const details = (data as { details?: unknown }).details;
+  if (details === undefined || details === null) {
+    return undefined;
+  }
+  const rendered = redactSensitiveText(stringifyNonErrorCause(details)).trim();
+  return rendered.length > 0 ? rendered : undefined;
+}
+
+function messageWithAcpRequestErrorDetails(error: Error): string {
+  const details = readAcpRequestErrorDetails(error);
+  if (!details || error.message.includes(details)) {
+    return error.message;
+  }
+  return `${error.message}: ${details}`;
+}
+
 export function isAcpRuntimeError(value: unknown): value is AcpRuntimeError {
   return value instanceof AcpRuntimeError || getForeignAcpRuntimeError(value) !== null;
 }
@@ -62,9 +87,13 @@ export function toAcpRuntimeError(params: {
     });
   }
   if (params.error instanceof Error) {
-    return new AcpRuntimeError(params.fallbackCode, params.error.message, {
-      cause: params.error,
-    });
+    return new AcpRuntimeError(
+      params.fallbackCode,
+      messageWithAcpRequestErrorDetails(params.error),
+      {
+        cause: params.error,
+      },
+    );
   }
   return new AcpRuntimeError(params.fallbackCode, params.fallbackMessage, {
     cause: params.error,