NousResearch/hermes-agent

MCP stdio tool calls leaking unawaited coroutines

Cluster 96030. Data as of 2026-10-25 11:21 UTC

Nothing open on GitHub. Fix merged in #100920 on 2 Sep 2026. Check it covers your case.

open issues

open PRs

items grouped

Known?: Yes. 4 related items grouped here, 1 issue already closed.
Fix event: A fix was merged to main in PR #100920. Check it covers your case. No release data is tracked.
Tracker: The maintainers' tracker marks this resolved, deciding PR #100920. That is separate from the fix event.
Still open: Nothing open on GitHub.

Next step: read #100920, then check it covers your case.

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A bug in MCP stdio tool handling causes an unawaited watcher coroutine to be leaked on every tool call, triggering RuntimeWarning. Multiple fix attempts and related cleanup are tracked here.

Open issues0

No open issues.

Open PRs0

No open pull requests.

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

#100920 fix(mcp): stdio tool calls no longer leak an un-awaited watcher coroutine per call (#95938, salvage #96251)

merged to main

files: tests/tools/test_mcp_stdio_children_dead.py, tools/mcp_tool.py

2 PRs closed without merging

From the close comments: done elsewhere 1 · duplicate 1

#96251 fix(mcp): stop leaking an unawaited watcher coroutine per stdio tool call (salvage #96044) · done elsewhere → fe3e5dc, #100920
#100110 fix(mcp): don't instantiate _watch_stdio_children just to probe awaitability · duplicate → #96251

Closed issues · 1

Closed#96030[Bug] mcp_tool.py:6139 leaks coroutine via inspect.isawaitable() — RuntimeWarning on every MCP call

How this cluster was grouped

Link evidence (structural links throughout): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
Pairwise link density 0.50: the share of item 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.

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At a glance

Merged PRs: #100920
Closed issues: 1
Attempts: 2 PRs closed without merging
Fix link checked: 2 Sep 2026

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