Copilot desktop sessions die after ~3 minutes as GitHub credential registration expires, breaking built-in MCP server
TwoPatient · ghdev · 2026-09-19
A developer reports a fatal bug in GitHub Copilot desktop app 1.1.22 (macOS arm64): the per-session GitHub credential registration used by the built-in github-mcp-server (dynamic header provider) disappears 3–5 minutes after the CLI process spawns.
- The server initializes fine, but the first call to any of its tools (e.g. websearch) fails with a header-provider error
- The MCP tool catalog is marked stale, every subsequent model turn fails until the session ends with session.end reason: error, and background sub-agents die with it
- The UI tells users to re-authenticate, but the built-in server isn't listed in the MCP list, so there's nothing to re-auth; three app restarts didn't help
- The standalone CLI 1.0.86 on the same machine/account is unaffected, and gh commands with the exported token keep working
Repro: create a new worktree session, wait 3 minutes, then ask the agent to call any github-mcp-server tool.
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