# NousResearch/hermes-agent · MCP stdio tool calls leak un-awaited coroutine

## Open now

- 0 issues, 1 PR open on GitHub.
- PR #100478: fix(mcp): close leaked coroutine in stdio fast-fail gate (Closes #100472)

A bug causes an un-awaited watcher coroutine to be leaked on every MCP stdio tool call, producing RuntimeWarnings. Multiple fixes target this coroutine leak in the stdio fast-fail gate.

## TL;DR

- 4 member(s): 0 open issue(s), 1 closed issue(s), 1 open PR(s), 1 merged PR(s), 1 PR(s) closed without merging.
- A fix was merged to main in PR #100920. Verify it addresses your case.
- **Recommended:** read PR #100920 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `resolved` · deciding PR(s): `pr-100920`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.50`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #100472: MCP stdio tool calls leak an un-awaited coroutine (RuntimeWarning on every call)

## Prior & competing PRs

- **#100920: fix(mcp): stdio tool calls no longer leak an un-awaited watcher coroutine per call (#95938, salvage #96251)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `tests/tools/test_mcp_stdio_children_dead.py`, `tools/mcp_tool.py`
- **#100476: fix(mcp): close leaked coroutine in stdio fast-fail gate**. closed without merge
  - maintainer direction: category `silent_close`; implication `active`
- **#100478: fix(mcp): close leaked coroutine in stdio fast-fail gate (Closes #100472)**. open
  - maintainer direction: category `duplicate_of`; implication `duplicate`; refs `#96251`
  - files: `tools/mcp_tool.py`

## Fix status

- Merged to main in PR #100920 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-02`.
- Subsystem: `mcp`