Add Chrome support to autowebcompat repro agent

agents/autowebcompat-repro/Dockerfile

@@ -28,17 +28,21 @@ ENV PATH="/opt/venv/bin:$PATH"
 
 FROM base AS agent
 
-# The Firefox DevTools MCP server is an npm package launched via `npx`, so the
-# agent image needs Node.js + npm (the python base ships neither). It also
-# needs the shared libraries Firefox requires to run headless; the Firefox
-# binary itself is downloaded at agent startup (a fresh Nightly per run) via
-# mozdownload/mozinstall, not baked in here.
+# The Firefox and Chrome DevTools MCP servers are npm packages launched via
+# `npx`, so the agent image needs Node.js + npm (the python base ships neither).
+# It also needs the shared libraries the browsers require to run headless. The
+# browser binaries themselves are downloaded at agent startup (a fresh build per
+# run): Firefox Nightly via mozdownload/mozinstall, Chrome for Testing
+# from https://googlechromelabs.github.io/chrome-for-testing/
 RUN apt-get update \
     && apt-get install -y --no-install-recommends \
         nodejs npm \
         ca-certificates \
-        libgtk-3-0 libdbus-glib-1-2 libx11-xcb1 libxtst6 libxt6 \
-        libasound2 libpci3 \
+        libgtk-3-0 libdbus-glib-1-2 libx11-xcb1 libxtst6 libxt6 libpci3 \
+        libnss3 libnspr4 libatk1.0-0t64 libatk-bridge2.0-0t64 libatspi2.0-0t64 \
+        libcups2t64 libdbus-1-3 libgbm1 libxcomposite1 libxdamage1 libxfixes3 \
+        libxrandr2 libxkbcommon0 libasound2t64 libpango-1.0-0 libcairo2 \
+        fonts-liberation \
     && rm -rf /var/lib/apt/lists/*
 
 # hackbot.toml lives at the agent root (not inside the package), so copy it into

agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/agent.py

@@ -27,7 +27,9 @@
 from hackbot_runtime.claude import Reporter
 from pydantic import BaseModel
 
-from .config import BUGZILLA_READ_TOOLS, DEVTOOLS_TOOLS
+from .chrome_devtools_mcp import build_chrome_devtools_server
+from .chrome_install import install_chrome
+from .config import BUGZILLA_READ_TOOLS, CHROME_DEVTOOLS_TOOLS, DEVTOOLS_TOOLS
 from .devtools_mcp import build_devtools_server
 from .firefox_install import install_firefox_nightly
 from .result import (
@@ -76,6 +78,7 @@ class AutowebcompatReproResult(BaseModel):
     failure_reason: str | None
     steps: str
     screenshot_path: str | None
+    chrome_reproduced: bool | None = None
     chrome_mask_fixed: bool | None = None
 
 
@@ -240,6 +243,7 @@ def __init__(
         run_tracker: RunTracker,
         firefox_path: Path,
         profile_path: Path,
+        chrome_path: Path,
         input_data: AutoWebcompatInput,
         bugzilla_mcp_server: McpServerConfig,
         screenshot_dir: Path,
@@ -260,6 +264,11 @@ def __init__(
             ),
             DEVTOOLS_TOOLS,
         )
+        self.add_mcp_server(
+            "chrome-devtools",
+            build_chrome_devtools_server(chrome_path=chrome_path, headless=True),
+            CHROME_DEVTOOLS_TOOLS,
+        )
         if self.input_data.type == "bug_id" != None:
             self.add_mcp_server("bugzilla", bugzilla_mcp_server, BUGZILLA_READ_TOOLS)
 
@@ -273,16 +282,24 @@ def system_prompt(self) -> str:
             .format(
                 task_details=f"""
 1. Identify the affected URL and the described broken behavior.
-2. Baseline: Navigate to the URL with the Firefox DevTools MCP and
-   try to reproduce the described broken behaviour.
-3. If the issue reproduces AND the breakage is visual in nature (incorrect
-   layout or rendering, not broken interaction), capture a screenshot showing
-   it: call `screenshot_page` with `saveTo` set to `{self.screenshot_path}`.
-   This writes the image to that file instead of returning it — do not capture
-   or paste the image data yourself. Then set `screenshot_path` in your result
-   to exactly `{self.screenshot_path}`. For non-visual issues, take no
-   screenshot and leave `screenshot_path` null.
-4. Submit your findings via `submit_result` (see "Reporting your result").
+2. Baseline: Navigate to the URL with the Firefox DevTools MCP
+   (`mcp__firefox-devtools__*` tools) and try to reproduce the described broken
+   behaviour. This determines `reproduced`.
+3. If the issue reproduces in Firefox AND the breakage is visual in nature
+   (incorrect layout or rendering, not broken interaction), capture a screenshot
+   showing it: call `screenshot_page` with `saveTo` set to
+   `{self.screenshot_path}`. This writes the image to that file instead of
+   returning it — do not capture or paste the image data yourself. Then set
+   `screenshot_path` in your result to exactly `{self.screenshot_path}`. For
+   non-visual issues, take no screenshot and leave `screenshot_path` null.
+4. Cross-browser check in Chrome (always run this, regardless of whether the
+   issue reproduced in Firefox): re-run the exact same reproduction steps using
+   the Chrome DevTools MCP (`mcp__chrome-devtools__*` tools), starting from a
+   fresh `new_page`. Judge whether the same broken behaviour appears in Chrome
+   and set `chrome_reproduced` accordingly (true = also broken in Chrome,
+   false = Chrome behaves correctly). An issue that reproduces in Firefox but
+   not in Chrome is a strong signal of a Firefox-specific webcompat problem.
+5. Submit your findings via `submit_result` (see "Reporting your result").
 """
             )
         )
@@ -372,6 +389,7 @@ async def run_autowebcompat_repro(
     :class:`AgentError` if the agent ends in an error.
     """
     nightly_path = install_firefox_nightly()
+    chrome_path = install_chrome()
 
     screenshots_dir = Path(tempfile.mkdtemp(prefix="autowebcompat-screenshots-"))
 
@@ -381,6 +399,7 @@ async def run_autowebcompat_repro(
         tracker,
         nightly_path,
         setup_profile(nightly_path, extensions=[]),
+        chrome_path,
         input_data,
         bugzilla_mcp_server,
         screenshots_dir,
@@ -400,6 +419,7 @@ async def run_autowebcompat_repro(
         failure_reason=repro_result.failure_reason,
         steps=repro_result.steps,
         screenshot_path=screenshot_path,
+        chrome_reproduced=repro_result.chrome_reproduced,
     )
 
     if repro_result.reproduced:

agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/chrome_devtools_mcp.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from claude_agent_sdk.types import McpStdioServerConfig
+
+PACKAGE = "chrome-devtools-mcp@latest"
+
+
+def build_chrome_devtools_server(
+    chrome_path: Path | None = None,
+    *,
+    headless: bool = True,
+    no_sandbox: bool = True,
+) -> McpStdioServerConfig:
+    """Build the stdio config for the Chrome DevTools MCP server.
+
+    Args:
+        chrome_path: Chrome binary to drive (the Chrome for Testing build from
+            ``chrome_install.install_chrome``). When ``None`` the server lets its
+            bundled Puppeteer discover a Chrome installation itself.
+        headless: Run Chrome without a visible window (required in
+            container/CI environments).
+        no_sandbox: Pass ``--no-sandbox`` to Chrome. Required when running as an
+            unprivileged user inside a container, where Chrome's setuid sandbox
+            cannot initialize and the browser otherwise fails to launch.
+    """
+    args = ["-y", PACKAGE]
+    if headless:
+        args.append("--headless")
+    if chrome_path is not None:
+        args += ["--executablePath", str(chrome_path)]
+
+    # Opt out of the MCP server's own data collection: its usage statistics and
+    # the CrUX API calls that send performance-trace URLs to Google. This does
+    # not touch Chrome's own behavior, only what the MCP server itself reports.
+    args += ["--usageStatistics=false", "--performanceCrux=false"]
+
+    if no_sandbox:
+        args += ["--chromeArg=--no-sandbox", "--chromeArg=--disable-setuid-sandbox"]
+
+    return McpStdioServerConfig(command="npx", args=args)

agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/chrome_install.py

@@ -0,0 +1,111 @@
+from __future__ import annotations
+
+import logging
+import platform
+import shutil
+import stat
+import sys
+import zipfile
+from pathlib import Path
+
+import requests
+
+VERSIONS_URL = (
+    "https://googlechromelabs.github.io/chrome-for-testing/"
+    "last-known-good-versions-with-downloads.json"
+)
+CHANNEL = "Stable"
+PLATFORM = "linux64"
+INSTALL_DIR = Path.home() / "chrome"
+DOWNLOAD_TIMEOUT = 120
+CHUNK_SIZE = 1 << 20
+
+logger = logging.getLogger("autowebcompat-repro")
+
+
+def reset_install_dir(install_dir: Path) -> None:
+    if install_dir.exists():
+        shutil.rmtree(install_dir)
+    install_dir.mkdir(parents=True)
+
+
+def resolve_download_url() -> str:
+    """Look up the Stable channel's Chrome download URL from the API."""
+    response = requests.get(VERSIONS_URL, timeout=DOWNLOAD_TIMEOUT)
+    response.raise_for_status()
+    data = response.json()
+
+    channel = data["channels"][CHANNEL]
+    logger.info("Chrome for Testing %s: version %s", CHANNEL, channel["version"])
+
+    downloads = channel["downloads"]["chrome"]
+    for download in downloads:
+        if download["platform"] == PLATFORM:
+            return download["url"]
+
+    raise RuntimeError(
+        f"no Chrome for Testing '{PLATFORM}' download in {CHANNEL} channel"
+    )
+
+
+def download_archive(url: str, install_dir: Path) -> Path:
+    archive = install_dir / f"chrome-{PLATFORM}.zip"
+
+    logger.info("downloading Chrome for Testing from %s", url)
+    with requests.get(url, stream=True, timeout=DOWNLOAD_TIMEOUT) as response:
+        response.raise_for_status()
+        with archive.open("wb") as out:
+            for chunk in response.iter_content(chunk_size=CHUNK_SIZE):
+                if chunk:
+                    out.write(chunk)
+
+    return archive
+
+
+def extract_archive(archive: Path, install_dir: Path) -> None:
+    with zipfile.ZipFile(archive) as zf:
+        zf.extractall(install_dir)
+    archive.unlink()
+
+
+def chrome_binary_path(install_dir: Path) -> Path:
+    binary = install_dir / f"chrome-{PLATFORM}" / "chrome"
+
+    if not binary.exists():
+        raise RuntimeError(f"Chrome binary not found at {binary} after unpacking")
+
+    return binary
+
+
+def ensure_executable(binary: Path) -> None:
+    # zipfile does not preserve the executable bit; restore it.
+    binary.chmod(binary.stat().st_mode | stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)
+
+
+def require_amd64_linux() -> None:
+    machine = platform.machine().lower()
+
+    if sys.platform == "linux" and machine in {"x86_64", "amd64"}:
+        return
+
+    raise RuntimeError(
+        "Chrome for Testing is only supported on linux/amd64 here; got "
+        f"{sys.platform}/{platform.machine()}. Run the agent image as "
+        "linux/amd64, e.g. DOCKER_DEFAULT_PLATFORM=linux/amd64."
+    )
+
+
+def install_chrome() -> Path:
+    """Download Chrome for Testing and return the browser binary path."""
+    require_amd64_linux()
+    reset_install_dir(INSTALL_DIR)
+
+    url = resolve_download_url()
+    archive = download_archive(url, INSTALL_DIR)
+    extract_archive(archive, INSTALL_DIR)
+
+    binary = chrome_binary_path(INSTALL_DIR)
+    ensure_executable(binary)
+
+    logger.info("installed Chrome at %s", binary)
+    return binary

agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/config.py

@@ -42,3 +42,31 @@
     "mcp__firefox-devtools__get_firefox_info",
     "mcp__firefox-devtools__get_firefox_output",
 ]
+
+# Chrome DevTools MCP tools (chrome-devtools-mcp), exposed under the
+# "chrome-devtools" server name. Web-compat reproduction subset mirroring the
+# Firefox list: page navigation, accessibility snapshots + UID-based
+# interaction, console/network inspection, screenshots, and scripted DOM
+# probing (evaluate_script).
+CHROME_DEVTOOLS_TOOLS = [
+    "mcp__chrome-devtools__list_pages",
+    "mcp__chrome-devtools__new_page",
+    "mcp__chrome-devtools__navigate_page",
+    "mcp__chrome-devtools__select_page",
+    "mcp__chrome-devtools__close_page",
+    "mcp__chrome-devtools__take_snapshot",
+    "mcp__chrome-devtools__click",
+    "mcp__chrome-devtools__hover",
+    "mcp__chrome-devtools__fill",
+    "mcp__chrome-devtools__fill_form",
+    "mcp__chrome-devtools__drag",
+    "mcp__chrome-devtools__upload_file",
+    "mcp__chrome-devtools__list_console_messages",
+    "mcp__chrome-devtools__list_network_requests",
+    "mcp__chrome-devtools__get_network_request",
+    "mcp__chrome-devtools__take_screenshot",
+    "mcp__chrome-devtools__evaluate_script",
+    "mcp__chrome-devtools__handle_dialog",
+    "mcp__chrome-devtools__wait_for",
+    "mcp__chrome-devtools__resize_page",
+]

agents/autowebcompat-repro/hackbot_agents/autowebcompat_repro/result.py

@@ -77,6 +77,16 @@ class ReproductionResult(BaseModel):
             layout rather than broken interaction. Otherwise it must be null."""
         ),
     )
+    chrome_reproduced: bool = Field(
+        description=(
+            "Result of re-running the same reproduction steps in Chrome (via the "
+            "Chrome DevTools MCP): true if the issue also reproduced in Chrome, "
+            "false if Chrome behaved correctly. Chrome is always tested, "
+            "regardless of the Firefox outcome. When it reproduces in Firefox "
+            "but not in Chrome, that indicates a Firefox-specific webcompat "
+            "issue."
+        ),
+    )
 
     @field_validator("screenshot_path", mode="after")
     @classmethod