asap-protocol · cursor · Sep 7, 2026
@@ -82,6 +82,8 @@ function createMockBrowserTree() {
     mockClick,
     mockFill,
     mockContent,
+    mockUrl,
+    mockEvalAnchors,
     contextClose,
     browserClose,
   };
@@ -153,6 +155,46 @@ describe("BrowserRuntime", () => {
     await rt.shutdown();
   });
 
+  it("redacts URL userinfo from navigate and snapshot outputs", async () => {
+    const { browser, mockUrl, mockContent, mockEvalAnchors } =
+      createMockBrowserTree();
+    mockUrl.mockReturnValue("https://alice:s3cret@page.example/path");
+    mockContent.mockResolvedValue(
+      '<html><body><a href="https://alice:s3cret@page.example/x">x</a></body></html>',
+    );
+    mockEvalAnchors.mockImplementation(
+      async (
+        _selector: string,
+        pageFunction: (
+          anchors: { href: string; textContent: string }[],
+          max: number,
+        ) => unknown,
+        max: number,
+      ) =>
+        pageFunction(
+          [{ href: "https://alice:s3cret@page.example/x", textContent: "x" }],
+          max,
+        ),
+    );
+    mockChromiumLaunch.mockResolvedValueOnce(browser);
+
+    const rt = new BrowserRuntime({ headless: true });
+    const { sessionId } = await rt.createSession();
+    const nav = await rt.navigate({
+      action: "navigate",
+      sessionId,
+      url: "https://alice:s3cret@example.com/",
+    });
+    expect(nav.url).toBe("https://page.example/path");
+    expect(nav.url).not.toContain("s3cret");
+
+    const snap = await rt.snapshot({ action: "snapshot", sessionId });
+    expect(snap.url).toBe("https://page.example/path");
+    expect(snap.htmlSnippet).not.toContain("s3cret");
+    expect(snap.links?.[0]?.href).toBe("https://page.example/x");
+    await rt.shutdown();
+  });
+
   it("clicks and types", async () => {
     const { mockClick, mockFill, browser } = createMockBrowserTree();
     mockChromiumLaunch.mockResolvedValueOnce(browser);

@@ -19,6 +19,12 @@ import {
   WebchainRuntimeError,
 } from "./runtime-error.js";
 import { extractLandmarks, extractPageLinks } from "./snapshot-helpers.js";
+import {
+  stripUserinfoDeep,
+  stripUserinfoFromLinks,
+  stripUserinfoFromText,
+  stripUserinfoFromUrl,
+} from "./url-redact.js";
 
 export interface BrowserRuntimeOptions {
   headless?: boolean;
@@ -103,11 +109,7 @@ export class BrowserRuntime {
       throw mapCommandFailure(error);
     }
 
-    return {
-      sessionId: command.sessionId,
-      url: session.page.url(),
-      title: await session.page.title(),
-    };
+    return actionResult(command.sessionId, session.page);
   }
 
   async snapshot(command: SnapshotCommand): Promise<SnapshotResult> {
@@ -150,12 +152,15 @@ export class BrowserRuntime {
       }
       return {
         sessionId: command.sessionId,
-        url: page.url(),
+        url: stripUserinfoFromUrl(page.url()),
         title: await page.title(),
-        htmlSnippet: summarizeHtml(html),
-        domSummary,
-        accessibilityTree: accessibilityJson,
-        links,
+        htmlSnippet: stripUserinfoFromText(summarizeHtml(html)),
+        domSummary:
+          domSummary === undefined
+            ? undefined
+            : stripUserinfoFromText(domSummary),
+        accessibilityTree: stripUserinfoDeep(accessibilityJson),
+        links: links === undefined ? undefined : stripUserinfoFromLinks(links),
         landmarks,
       };
     } catch (error) {
@@ -171,11 +176,7 @@ export class BrowserRuntime {
       throw mapCommandFailure(error);
     }
 
-    return {
-      sessionId: command.sessionId,
-      url: session.page.url(),
-      title: await session.page.title(),
-    };
+    return actionResult(command.sessionId, session.page);
   }
 
   async type(command: TypeCommand): Promise<ActionResult> {
@@ -186,11 +187,7 @@ export class BrowserRuntime {
       throw mapCommandFailure(error);
     }
 
-    return {
-      sessionId: command.sessionId,
-      url: session.page.url(),
-      title: await session.page.title(),
-    };
+    return actionResult(command.sessionId, session.page);
   }
 
   async closeSession(
@@ -247,6 +244,17 @@ export {
   WebchainRuntimeError,
 } from "./runtime-error.js";
 
+async function actionResult(
+  sessionId: string,
+  page: Page,
+): Promise<ActionResult> {
+  return {
+    sessionId,
+    url: stripUserinfoFromUrl(page.url()),
+    title: await page.title(),
+  };
+}
+
 export function summarizeHtml(html: string, limit = 1600) {
   return html.replace(/\s+/g, " ").trim().slice(0, limit);
 }

@@ -39,6 +39,15 @@ describe("mapCommandFailure", () => {
     expect(err.code).toBe("COMMAND_FAILED");
     expect(err.message).toContain("timed out");
   });
+
+  it("redacts URL userinfo from Playwright error messages", () => {
+    const err = mapCommandFailure(
+      new Error("net::ERR_FAILED at https://alice:s3cret@127.0.0.1/x"),
+    );
+    expect(err.code).toBe("COMMAND_FAILED");
+    expect(err.message).not.toContain("s3cret");
+    expect(err.message).toContain("https://127.0.0.1/x");
+  });
 });
 
 describe("isExecutableMissingMessage", () => {

@@ -1,4 +1,5 @@
 import type { RuntimeErrorCode } from "@webchain/protocol";
+import { stripUserinfoFromText } from "./url-redact.js";
 
 const INSTALL_HINT =
   "Playwright browser binaries are missing. Run: pnpm --filter @webchain/runtime exec playwright install chromium";
@@ -57,10 +58,11 @@ export function mapCommandFailure(error: unknown): WebchainRuntimeError {
   }
 
   const message = error instanceof Error ? error.message : String(error);
+  const redacted = stripUserinfoFromText(message);
 
   return new WebchainRuntimeError(
     "COMMAND_FAILED",
-    message || "Command failed.",
+    redacted || "Command failed.",
     { cause: error },
   );
 }
@@ -0,0 +1,83 @@
+import { describe, expect, it } from "vitest";
+import {
+  stripUserinfoDeep,
+  stripUserinfoFromLinks,
+  stripUserinfoFromText,
+  stripUserinfoFromUrl,
+} from "./url-redact.js";
+
+describe("stripUserinfoFromUrl", () => {
+  it("removes user and password from http(s) URLs", () => {
+    expect(
+      stripUserinfoFromUrl("https://alice:s3cret@example.com/path?q=1"),
+    ).toBe("https://example.com/path?q=1");
+  });
+
+  it("removes username-only userinfo", () => {
+    expect(stripUserinfoFromUrl("https://alice@example.com/")).toBe(
+      "https://example.com/",
+    );
+  });
+
+  it("leaves URLs without userinfo unchanged", () => {
+    expect(stripUserinfoFromUrl("https://example.com/x")).toBe(
+      "https://example.com/x",
+    );
+  });
+
+  it("omits data: payloads so embedded credentials cannot hide in page.url()", () => {
+    const dataUrl =
+      "data:text/html," +
+      encodeURIComponent(
+        '<a href="https://alice:pw-in-href@example.org/path">l</a>',
+      );
+    const redacted = stripUserinfoFromUrl(dataUrl);
+    expect(redacted).toBe("data:text/html,");
+    expect(redacted).not.toContain("pw-in-href");
+  });
+
+  it("falls back to text stripping for non-URL strings", () => {
+    expect(
+      stripUserinfoFromUrl("see https://bob:pw@example.net/a and more"),
+    ).toBe("see https://example.net/a and more");
+  });
+});
+
+describe("stripUserinfoFromText", () => {
+  it("redacts credentials in HTML hrefs", () => {
+    const html = '<a href="https://alice:pw-in-href@example.org/path">link</a>';
+    expect(stripUserinfoFromText(html)).toBe(
+      '<a href="https://example.org/path">link</a>',
+    );
+  });
+
+  it("does not treat mailto addresses as userinfo URLs", () => {
+    expect(stripUserinfoFromText("contact mailto:user@example.com")).toBe(
+      "contact mailto:user@example.com",
+    );
+  });
+});
+
+describe("stripUserinfoFromLinks", () => {
+  it("redacts href and preserves link text", () => {
+    expect(
+      stripUserinfoFromLinks([
+        { href: "https://u:p@example.com/x", text: "x" },
+      ]),
+    ).toEqual([{ href: "https://example.com/x", text: "x" }]);
+  });
+});
+
+describe("stripUserinfoDeep", () => {
+  it("redacts nested strings", () => {
+    expect(
+      stripUserinfoDeep({
+        url: "https://u:p@example.com/",
+        items: ["https://a:b@example.net/"],
+      }),
+    ).toEqual({
+      url: "https://example.com/",
+      items: ["https://example.net/"],
+    });
+  });
+});
@@ -0,0 +1,70 @@
+/**
+ * Strip URL userinfo so basic-auth credentials are not echoed to companion/MCP.
+ * Playwright `page.url()` and `HTMLAnchorElement.href` preserve `user:pass@`.
+ */
+
+/** Matches `scheme://userinfo@` including `user@host` and `user:pass@host`. */
+const USERINFO_IN_ABSOLUTE_URL =
+  /([a-zA-Z][a-zA-Z0-9+.-]*:\/\/)([^/\s"'<>@]+@)/g;
+
+/**
+ * Remove embedded credentials from a single URL.
+ *
+ * @example
+ * stripUserinfoFromUrl("https://alice:pw@example.com/x")
+ * // => "https://example.com/x"
+ */
+export function stripUserinfoFromUrl(url: string): string {
+  try {
+    const parsed = new URL(url);
+    if (parsed.protocol === "data:") {
+      // data: URLs are the document; echoing the payload repeats href userinfo
+      // in percent-encoded form (not matched by the userinfo regex).
+      const comma = url.indexOf(",");
+      const withoutPayload = comma === -1 ? url : url.slice(0, comma + 1);
+      return stripUserinfoFromText(withoutPayload);
+    }
+    if (parsed.username !== "" || parsed.password !== "") {
+      parsed.username = "";
+      parsed.password = "";
+    }
+    return stripUserinfoFromText(parsed.href);
+  } catch {
+    return stripUserinfoFromText(url);
+  }
+}
+
+/**
+ * Remove `user:pass@` (or `user@`) from any absolute URLs inside free-form text.
+ */
+export function stripUserinfoFromText(text: string): string {
+  return text.replace(USERINFO_IN_ABSOLUTE_URL, "$1");
+}
+
+/** Redact `href` on extracted snapshot links. */
+export function stripUserinfoFromLinks(
+  links: { href: string; text: string }[],
+): { href: string; text: string }[] {
+  return links.map((link) => ({
+    ...link,
+    href: stripUserinfoFromUrl(link.href),
+  }));
+}
+
+/** Walk JSON-like snapshot trees and redact URLs in string leaves. */
+export function stripUserinfoDeep(value: unknown): unknown {
+  if (typeof value === "string") {
+    return stripUserinfoFromText(value);
+  }
+  if (Array.isArray(value)) {
+    return value.map(stripUserinfoDeep);
+  }
+  if (value !== null && typeof value === "object") {
+    const out: Record<string, unknown> = {};
+    for (const [key, child] of Object.entries(value)) {
+      out[key] = stripUserinfoDeep(child);
+    }
+    return out;
+  }
+  return value;
+}