The External Connect modal's Codex and OpenClaw tabs were rendering
this MCP server config:
command = "python3"
args = ["-m", "molecule_runtime.a2a_mcp_server"]
That spawns the bare MCP dispatcher with no presence wiring. The
``molecule-mcp`` console-script wrapper (mcp_cli.main) is what calls
``POST /registry/register`` at startup and runs the 20s heartbeat
thread alongside the MCP stdio loop. Without the wrapper, the canvas
flips the workspace back to ``awaiting_agent`` (OFFLINE) within
60-90s — even while tools work — because nothing is heartbeating.
Operator-side this looks like: the workspace is registered and tools
work fine when invoked, but the canvas shows "offline" / "Restart"
CTA, peer agents see the workspace as awaiting_agent in list_peers
output, and inbound A2A delivery silently fails the readiness check.
A new external-Codex operator (#2957) hit this and spent debugging
time on what should have been a copy-paste install.
Fix: switch both Codex and OpenClaw templates to
``command = "molecule-mcp"`` / ``args = []``, matching the universal
MCP template that already handles this correctly. Inline comment in
each template explains the wrapper-vs-bare-module tradeoff so a
future template author doesn't regress to the shorter form.
Hermes-channel intentionally still spawns the bare module — the
hermes plugin owns the platform plugin path and runs its own
register_platform/heartbeat code in-process; double-heartbeating
would race. Universal/Codex/OpenClaw all need the wrapper.
Regression gate: TestExternalMcpTemplates_UseMoleculeMcpWrapper
asserts the three templates that must use the wrapper actually do,
and explicitly fails on the old ``-m molecule_runtime.a2a_mcp_server``
shape. Verified the test FAILS on pre-fix source by stashing only
external_connection.go and re-running.
Source: molecule-core#2957 issue 1 (item 4 of the report — the
``(codex returned empty output)`` / opaque-canvas-error / stale-
session items live in codex-channel-molecule and are tracked
separately).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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