GitHub Copilot coding agent always return Error: page.goto: net::ERR_BLOCKED_BY_CLIENT

[doggy8088]

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I tried to add domain to Custom allowlist, also tried turn off the Firewall from GitHub Copilot coding agent.

Here is my prompt:

I need a screenshot of the https://context7.com/ and put it into README.md

Any idea?

[doggy8088]

Not only Playwright MCP. All MCP unable to connect to any host. The firewall is ALWAYS ON now.

[doggy8088]

I requested GitHub support. It seems not accepted. There is no one response to me.

[thomasturrell]

A possible workaround would be to add guidance in .github/copilot-instructions.md asking Copilot to use curl instead of Playwright, although this only works for non-SPA endpoints and will not help with routes that rely on client-side rendering.

[seanbearden]

+1 — hitting the same behavior in the hosted Copilot coding agent today.

Relevant context I confirmed from GitHub's own docs that isn't loud enough in the current community threads:

From docs.github.com/en/copilot/reference/copilot-allowlist-reference and the agent firewall customization page:

Only applies to processes started by the agent via its Bash tool. It does not apply to Model Context Protocol (MCP) servers or processes started in configured Copilot setup steps.

So the custom domain allowlist in Settings → Copilot → Coding agent is, by design, a Bash-tool-only allowlist — it does not and will not cover the inherited @playwright/mcp server's egress. That's the root of the ERR_BLOCKED_BY_CLIENT block page (which comes from @playwright/mcp's default origin filter, not Chrome Safe Browsing). This makes the symptom expected behavior rather than a bug, but it's a significant gap in how the product is marketed vs. what's documented in the allowlist UI.

Workarounds I found in other threads that are worth consolidating:

• PLAYWRIGHT_MCP_ALLOWED_ORIGINS env var is documented upstream in microsoft/playwright-mcp but reported as non-functional on the hosted cloud agent (see #178826).
• Declaring a user MCP server to shadow the default — feasibility reported as inconsistent across threads.
• Fall back to curl/gh from the Bash tool (governed by the documented allowlist) — works for non-SPA validation.
• Localhost tunnel (e.g., ngrok) into a setup step — sidesteps the MCP origin filter by keeping Playwright on its default localhost allowlist. Feasible.
• Self-hosted Copilot agent with custom mcp.config.json — the only path that fully removes the constraint, but out of scope for most users.

Would love a clarification from GitHub on two points:

1. Is the @playwright/mcp default-localhost behavior intentional for the hosted agent, and is there any planned path to extend the Bash-tool allowlist to also cover inherited MCP servers?
2. If not, could the allowlist UI surface a clearer "Bash-tool only" label? Right now it implies broader scope than it has.

(Filed internal tracking of this in our own repo for anyone with similar needs — the short version is: Playwright MCP in hosted coding agent is effectively a localhost-only tool for now; drive external envs via pytest -m e2e run from the Bash tool, not via MCP.)

[LukeSavefrogs]

• Localhost tunnel (e.g., ngrok) into a setup step

Also I proved using a reverse proxy works ahead of the application in the copilot setup steps works, but requires custom setup for every repo/application (e.g. port may differ between projects or in case of a multi-project monorepo)