Desktop-app sessions die a few minutes after spawn

Start by reproducing the failure using the listed worktree-session steps and inspect the process logs for copilot_runtime::session::mcp::tool_catalog and remote::api_session_exporter. Trace how the GitHub credential registration is used by github-mcp-server after spawn and how a stale catalog affects later turns. Done means the credential failure no longer terminates the app-hosted session or makes subsequent turns unusable.

Title: Desktop-app sessions die a few minutes after spawn: "GitHub credential registration is no longer available for this session" → stale github-mcp-server catalog treated as fatal

Environment

• GitHub Copilot desktop app 1.1.22 (commit c3daa01), macOS (arm64), bundled CLI 1.0.84-5

• Account: TwoPatient (github.com); gh auth status reports valid tokens (GH_TOKEN and keyring)

• Standalone CLI 1.0.86 (/opt/homebrew/bin/copilot) is not affected

Summary

In app-hosted sessions, the GitHub credential registration the CLI server uses for the built-in github-mcp-server (dynamic header provider) disappears a few minutes after the process spawns. github-mcp-server initialises fine at warm-up, but the first call to any of its tools (web_search, github-mcp-server-*) fails with a header-provider error, the MCP tool catalog is marked stale, and every subsequent model turn fails until the session ends with sessionEnd reason: error. Background sub-agents in the same process die too. App restarts (3×) did not help.

Steps to reproduce

1. Create a new worktree session in the app; wait ~2–3 minutes.

2. Ask the agent to call web_search (or any github-mcp-server-* tool).

3. Observe the tool error, then repeated session errors on the next turns, then the session terminates.

Actual

Tool result:

Plain text

MCP tool catalog changed before tool "github-mcp-server-web_search" could be invoked: Failed to verify cached MCP tools: MCP request failed: Transport send error: unexpected server response: dynamic header provider failed: GitHub credential registration is no longer available for this session

Followed by 5 × session.error:

Plain text

Execution failed: Failed to refresh MCP tools for server github-mcp-server; the last catalog is stale

then session.end reason: error — CLI process exits, worktree session unusable.

Process log (copilot_runtime::session::mcp::tool_catalog): 30+ Failed to list MCP tools for github-mcp-server; continuing with the previously listed tools: … GitHub credential registration is no longer available for this session. Processes that never call github-mcp tools show the same root symptom non-fatally in remote::api_session_exporter: remote session batch flush failed {"error":"GitHub credential authority error: GitHub token provider registration \"<uuid>\" is unavailable"} from ~2 s after spawn.