René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Docker stdio MCP servers duplicated on /new and /resume (v1.0.68)","articleBody":"## Summary\n\nOn **v1.0.68**, running `/new` or `/resume` (resuming a session not started during the current CLI run) spawns a **fresh set of stdio MCP `docker run` clients without tearing down the previous set**. Duplicates accumulate within the **same** CLI process for its entire lifetime.\n\nThis looks related to #3440 but is a **different code path**: #3440 was about `session.disconnect()` not killing stdio processes (fixed in 1.0.51). Here, **no disconnect happens at all** — the CLI re-initializes MCP servers on `/new`/`/resume` and spawns a new set while the old set stays connected, so the kill-on-disconnect logic never runs.\n\n## Environment\n\n- Copilot CLI **1.0.68**\n- macOS (Darwin arm64)\n- MCP servers configured as stdio Docker containers (`docker run -i --rm …`) in `~/.copilot/mcp-config.json` — one `github-mcp-server` + three `grafana` instances\n\n## Actual behavior\n\nEvery configured stdio MCP server is duplicated per `/new` or `/resume`. `docker ps` shows 2× (or more) of every server, all parented to the same live `copilot` process. Because the containers run with `--rm`, they only self-remove when the whole CLI exits — so they pile up for the entire CLI session.\n\n## Affected version\n\n1.0.68\n\n## Steps to reproduce the behavior\n\n1. Configure one or more stdio Docker-based MCP servers.\n2. Start the CLI (session A) → one set of `docker run` clients spawns.\n3. Run `/new`, **or** `/resume` a session that was **not** opened during the current CLI run.\n4. A second set of clients spawns; the first set is **not** disconnected.\n\n## Expected behavior\n\nOn `/new` or `/resume`, the CLI should either **reuse** the existing MCP server connections or **disconnect** the outgoing session's stdio MCP servers before starting new ones.\n\n## Additional context\n\n### Evidence\n\nSingle `copilot` PID `71692`, alive ~19 min, holding **two full sets** spawned ~2 min apart — none orphaned, all share that PID as parent:\n\n```console\n$ ps -eo pid,ppid,etime,command | grep '[d]ocker run'\n72222 71692 19:12 docker run -i --rm --network host … github-mcp-server\n72225 71692 19:11 docker run -i --rm … grafana/mcp-grafana -t stdio\n72226 71692 19:11 docker run -i --rm … grafana/mcp-grafana -t stdio\n72227 71692 19:11 docker run -i --rm … grafana/mcp-grafana -t stdio\n72869 71692 17:32 docker run -i --rm --network host … github-mcp-server\n72870 71692 17:31 docker run -i --rm … grafana/mcp-grafana -t stdio\n72871 71692 17:31 docker run -i --rm … grafana/mcp-grafana -t stdio\n72880 71692 17:30 docker run -i --rm … grafana/mcp-grafana -t stdio\n\n$ docker ps --format '{{.Image}}' | sort | uniq -c\n   6 grafana/mcp-grafana\n   2 nexus…/github/github-mcp-server\n```\n\n### Impact\n\nResource leak: duplicated containers consume memory/CPU and, for named containers, cause `container \"x\" already exists` errors on the next spawn. The only reliable cleanup today is fully exiting the CLI.\n\n### Related\n\n- #3440 (fixed the disconnect path in 1.0.51; this is the `/new` + `/resume` re-init path, still leaking on 1.0.68)","author":{"url":"https://github.com/rjvq85","@type":"Person","name":"rjvq85"},"datePublished":"2026-07-07T13:00:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/4049/copilot-cli/issues/4049"}