diff --git a/src/agent/index.ts b/src/agent/index.ts
index 6b151cae..0f9455c4 100644
--- a/src/agent/index.ts
+++ b/src/agent/index.ts
@@ -16,6 +16,7 @@ import {
   saveOpenWikiEnv,
 } from "../env.js";
 import { isFileNotFoundError } from "../fs-errors.js";
+import { SECRET_KEY_PATTERN_SOURCE } from "../diagnostics.js";
 import { openWikiLocalWikiDir } from "../openwiki-home.js";
 import { OpenWikiLocalShellBackend } from "./docs-only-backend.js";
 import {
@@ -1261,8 +1262,15 @@ async function readResponseBodyPreview(response: Response): Promise<string> {
 }
 
 export function sanitizeOpenRouterResponseBody(body: string): string {
+  // Redact string values whose JSON key name contains any secret-bearing term
+  // (shared source of truth with isSecretLikeKey / the MCP redactor).
+  const secretJsonKeyPattern = new RegExp(
+    `"([^"]*(?:${SECRET_KEY_PATTERN_SOURCE})[^"]*)"\\s*:\\s*"[^"]*"`,
+    "giu",
+  );
+
   return body.replace(
-    /"([^"]*(?:api[-_]?key|authorization|bearer|password|secret|token|user_id)[^"]*)"\s*:\s*"[^"]*"/giu,
+    secretJsonKeyPattern,
     (_, key: string) => `${JSON.stringify(key)}:"[REDACTED]"`,
   );
 }
diff --git a/src/cli.tsx b/src/cli.tsx
index f264269a..a4c79124 100644
--- a/src/cli.tsx
+++ b/src/cli.tsx
@@ -33,7 +33,11 @@ import {
 } from "./env.js";
 import { createOpenWikiThreadId, runOpenWikiAgent } from "./agent/index.js";
 import { formatChatGptAccountFromEnv } from "./agent/openai-chatgpt-oauth.js";
-import { getErrorMessage, sanitizeDiagnosticText } from "./diagnostics.js";
+import {
+  getErrorMessage,
+  isSecretLikeKey,
+  sanitizeDiagnosticText,
+} from "./diagnostics.js";
 import { stripHtmlTags } from "./utils.js";
 import {
   type OpenWikiRunEvent,
@@ -3269,10 +3273,6 @@ function createDiagnosticJsonReplacer() {
   };
 }
 
-function isSecretLikeKey(key: string): boolean {
-  return /api[-_]?key|authorization|bearer|token|secret|password/iu.test(key);
-}
-
 function truncateDiagnosticValue(value: string): string {
   const maxLength = 2_000;
   const normalizedValue = value.trim();
diff --git a/src/connectors/mcp-runtime.ts b/src/connectors/mcp-runtime.ts
index 14463648..1140baaa 100644
--- a/src/connectors/mcp-runtime.ts
+++ b/src/connectors/mcp-runtime.ts
@@ -16,6 +16,7 @@ import type {
   ConnectorIngestResult,
   McpConnectorConfig,
 } from "./types.js";
+import { isSecretLikeKey } from "../diagnostics.js";
 
 export type McpConnectorId = Extract<ConnectorId, "notion">;
 
@@ -272,7 +273,3 @@ function sanitizeValue(value: unknown): unknown {
 
   return value;
 }
-
-function isSecretLikeKey(key: string): boolean {
-  return /(token|secret|password|authorization|api[-_]?key|cookie)/iu.test(key);
-}
diff --git a/src/diagnostics.ts b/src/diagnostics.ts
index ca840756..c6fefa8a 100644
--- a/src/diagnostics.ts
+++ b/src/diagnostics.ts
@@ -48,6 +48,27 @@ export function sanitizeDiagnosticText(value: string): string {
     .replace(/\bls[v_][A-Za-z0-9_-]+/gu, "[REDACTED:LANGSMITH_API_KEY]");
 }
 
+/**
+ * True when an object key name looks like it holds a credential, so its value
+ * should be redacted before display, logging, or persistence.
+ *
+ * This is a security boundary shared by every redaction path (diagnostics,
+ * OpenRouter response bodies, and MCP tool args/results). The term list is the
+ * union of every term the individual paths previously matched, so a key
+ * redacted by one path is redacted by all of them.
+ */
+/**
+ * The union of every substring that marks a key/field name as secret-bearing.
+ * Single source of truth for all redaction paths — extend this, not the
+ * individual call sites.
+ */
+export const SECRET_KEY_PATTERN_SOURCE =
+  "api[-_]?key|authorization|bearer|token|secret|password|user_id|cookie";
+
+export function isSecretLikeKey(key: string): boolean {
+  return new RegExp(SECRET_KEY_PATTERN_SOURCE, "iu").test(key);
+}
+
 /**
  * Recognizes an OpenRouter/provider 500 response so a friendlier, actionable
  * message can be shown instead of a raw stack trace.
diff --git a/test/redaction.test.ts b/test/redaction.test.ts
index 1908fa32..7ad32b1f 100644
--- a/test/redaction.test.ts
+++ b/test/redaction.test.ts
@@ -2,10 +2,59 @@ import { afterEach, beforeEach, describe, expect, test } from "vitest";
 import {
   getErrorMessage,
   isOpenRouterServerError,
+  isSecretLikeKey,
   sanitizeDiagnosticText,
 } from "../src/diagnostics.ts";
 import { sanitizeOpenRouterResponseBody } from "../src/agent/index.ts";
 
+describe("isSecretLikeKey", () => {
+  // The shared predicate must be the union of every term the three former
+  // implementations (cli.tsx, agent/index.ts, mcp-runtime.ts) matched, so a key
+  // redacted by one path is redacted by all of them.
+  test.each([
+    "apiKey",
+    "api_key",
+    "api-key",
+    "authorization",
+    "Bearer",
+    "access_token",
+    "refresh_token",
+    "client_secret",
+    "password",
+    "user_id",
+    "Cookie",
+  ])("flags secret-bearing key %s (case-insensitive)", (key) => {
+    expect(isSecretLikeKey(key)).toBe(true);
+    expect(isSecretLikeKey(key.toUpperCase())).toBe(true);
+  });
+
+  test.each(["email", "plan", "model", "count", "name", "url"])(
+    "does not flag benign key %s",
+    (key) => {
+      expect(isSecretLikeKey(key)).toBe(false);
+    },
+  );
+});
+
+describe("sanitizeOpenRouterResponseBody", () => {
+  test("redacts values for the unified secret key set", () => {
+    const body = JSON.stringify({
+      access_token: "should-be-hidden",
+      user_id: "u-123",
+      cookie: "session=abc",
+      model: "gpt-5.5",
+    });
+    const sanitized = sanitizeOpenRouterResponseBody(body);
+
+    expect(sanitized).not.toContain("should-be-hidden");
+    expect(sanitized).not.toContain("u-123");
+    expect(sanitized).not.toContain("session=abc");
+    expect(sanitized).toContain("[REDACTED]");
+    // Non-secret fields are preserved.
+    expect(sanitized).toContain("gpt-5.5");
+  });
+});
+
 describe("sanitizeDiagnosticText", () => {
   const originalOpenAiKey = process.env.OPENAI_API_KEY;
   const originalOpenAiCompatibleKey = process.env.OPENAI_COMPATIBLE_API_KEY;