Closes part of #2790 (Phase B). Prevents a recurrence of the PR #2766 →
PR #2771 cycle: PR #2766 added ``source_workspace_id`` to four tools'
``input_schema`` and tool implementations, but the dispatcher in
``a2a_mcp_server.handle_tool_call`` silently dropped the kwarg for
``commit_memory`` / ``recall_memory`` / ``chat_history`` /
``get_workspace_info``. Schema lied; LLMs populated the param; every
call fell back to ``WORKSPACE_ID``, defeating multi-tenant isolation.
Existing dispatcher tests asserted return-value substrings (``"working"
in result``) instead of kwarg flow, so the bug shipped to main and was
only caught by re-reviewing post-merge.
This change adds an AST-driven gate. For every ToolSpec in
platform_tools.registry.TOOLS, the gate finds the matching
``elif name == "<tool>"`` arm in a2a_mcp_server.py and asserts that
every property declared in input_schema.properties is read by an
``arguments.get("<property>", ...)`` call inside that arm. A new schema
field the dispatcher forgets to forward fails CI loudly.
Three tests:
- test_every_dispatch_arm_reads_every_schema_property: main drift gate.
Walks registry, matches dispatch arms by name, diffs declared vs
read keys.
- test_dispatch_arms_reach_every_registered_tool: inverse direction.
A registered tool with no dispatch arm is "Unknown tool" at runtime,
even though docs/wrappers/schema all advertise it. Catches PRs that
add a ToolSpec but forget the dispatcher.
- test_drift_gate_self_check_finds_known_arms: pin the AST parser. If
handle_tool_call is refactored into a different shape (dict dispatch,
registry-driven, etc.) and _load_dispatch_arms returns {}, the main
gate vacuously passes — this self-check makes that failure mode
explicit by requiring 12 known arms to be discovered.
Verified the gate catches the PR #2766 bug: stripping
``source_workspace_id=arguments.get(...)`` from the commit_memory arm
fails the gate with a descriptive error pointing at the missing kwarg
and referencing the prior incident. Restored → 3 tests pass.
Suite: 1733 passed (was 1730 + 3 new), 3 skipped, 2 xfailed.
Why AST, not runtime invocation: the runtime mock-based tests in
test_a2a_mcp_server.py already assert kwargs flow correctly for four
explicitly-tested tools. This gate is cheaper (~1ms), catches new
properties before someone has to remember the runtime test, and runs
as a structural invariant.
Phase A (Python coverage floor) and Phase C (molecule-mcp e2e harness)
remain in #2790 as separate follow-ups.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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