Support GHEC tenants (*.ghe.com) when proxying gh CLI and actions/github-script

[lpcox]

Context: How AWF api-proxy handles GHEC tenants today

The AWF firewall api-proxy sidecar (containers/api-proxy/server.js) has built-in GHEC tenant detection via deriveCopilotApiTarget(). When GITHUB_SERVER_URL points to a *.ghe.com tenant, it auto-derives the correct endpoints:

GITHUB_SERVER_URL=https://mycompany.ghe.com
  → Copilot inference: copilot-api.mycompany.ghe.com
  → GitHub REST API:   api.mycompany.ghe.com
  → Copilot telemetry: copilot-telemetry-service.mycompany.ghe.com

The AWF CLI (src/cli.ts) also auto-populates the firewall domain allowlist with all four GHEC subdomains when it detects a *.ghe.com server URL, and auto-injects GH_HOST=<tenant>.ghe.com into the agent environment so that gh CLI targets the correct instance.

For GHES (non-ghe.com, non-github.com), Copilot traffic routes to api.enterprise.githubcopilot.com.

Priority order for Copilot API target:

1. Explicit COPILOT_API_TARGET env var (or --copilot-api-target flag)
2. Auto-derived from GITHUB_SERVER_URL
3. Default: api.githubcopilot.com

Concern: MCP Gateway also needs GHEC awareness

When the MCP gateway proxies requests for tools like gh CLI and actions/github-script, those requests target the GitHub REST API — which on GHEC tenants lives at api.<subdomain>.ghe.com, not api.github.com.

If the MCP gateway hardcodes or assumes api.github.com as the GitHub API base, GHEC tenant workflows will fail when:

• gh CLI makes API calls (e.g., listing PRs, creating issues)
• actions/github-script runs Octokit requests
• Any MCP tool that calls the GitHub REST or GraphQL API

What needs to work

For a GHEC tenant like mycompany.ghe.com:

• gh api /repos/{owner}/{repo}/pulls → https://api.mycompany.ghe.com/repos/...
• GraphQL endpoint → https://api.mycompany.ghe.com/graphql
• Copilot models → https://copilot-api.mycompany.ghe.com/...

Questions

1. Does the MCP gateway currently read GITHUB_SERVER_URL / GITHUB_API_URL / GH_HOST to determine the correct API base?
2. If the MCP gateway routes traffic through AWF's Squid proxy, the GHEC domains are already in the allowlist — but does the gateway itself construct the correct upstream URL?
3. For GHES instances (e.g., github.mycompany.com), the REST API is at api.github.mycompany.com — is this handled?

Reference

• AWF api-proxy GHEC logic: containers/api-proxy/server.js deriveCopilotApiTarget()
• AWF CLI GHEC auto-detection: src/cli.ts extractGhecDomainsFromServerUrl()
• AWF GH_HOST injection: src/docker-manager.ts extractGhHostFromServerUrl()