[q] fix: disable Chromium sandbox in Playwright MCP to allow localhost access

[github-actions]

Q Workflow Optimization Report

Issues Found (from live data)

Workflow: Documentation Unbloat (unbloat-docs.md)

• Run Analyzed: §22288201364
• Issue Identified: Screenshots failed — Playwright browser process sandbox-isolated and could not reach localhost:4321 or 172.30.0.20 (ERR_CONNECTION_REFUSED)

Root Cause: Chromium's process sandbox creates isolated network namespaces for renderer processes, even when the Docker container itself uses --network host. The renderer process's network namespace doesn't inherit the host network, so it cannot connect to services (like the docs preview server) running on localhost.

Change Made

pkg/workflow/mcp_config_playwright_renderer.go

Added --browser-arg --no-sandbox to the default Playwright MCP entrypointArgs:

Before: ["--output-dir", "/tmp/gh-aw/mcp-logs/playwright"]
After:  ["--output-dir", "/tmp/gh-aw/mcp-logs/playwright", "--browser-arg", "--no-sandbox"]

The --browser-arg --no-sandbox flag is passed to the @playwright/mcp CLI, which forwards --no-sandbox as a Chromium browser launch argument. This disables Chromium's process sandbox, allowing renderer processes to access the host network (localhost, 172.x.x.x).

Security note: The Docker container already provides sufficient isolation via --security-opt seccomp=unconfined, --ipc=host, and --network host. Disabling Chromium's internal sandbox inside the container is the standard practice for containerized Playwright environments.

Why the existing Docker flags weren't enough

The Docker-level flags that were already present:

• --security-opt seccomp=unconfined — allows Chromium to use Linux syscalls for its sandbox
• --ipc=host — provides shared memory for Chromium processes

These enable Chromium's sandbox to start (preventing the "EOF" crash), but Chromium's sandbox still isolates renderer process network namespaces. The --no-sandbox flag is needed to allow renderers to reach localhost.

Expected Improvements

• All Playwright-based screenshot workflows (unbloat-docs, daily-multi-device-docs-tester, slide-deck-maintainer, weekly-editors-health-check, etc.) will be able to connect to locally-served sites
• Screenshots of local documentation builds will succeed

Note on Lock Files

Lock files (.lock.yml) will be regenerated automatically after this PR is merged and the binary is rebuilt with the updated Go code. The key change is in mcp_config_playwright_renderer.go which generates the entrypointArgs at compile time.

References

• Failing run: §22288201364
• Triggered by comment on issue [docs] docs: remove repetitive structural overhead from MemoryOps guide #17796

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[github-actions]

✅ Pull request created: #17808

[pelikhan]

@copilot recompile

[Copilot]

@pelikhan I've opened a new pull request, #17813, to work on those changes. Once the pull request is ready, I'll request review from you.