Support mcp 2.x (FastMCP -> MCPServer); stop skipping a broken server import - #8
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… import mcp 2.0.0 (released between 2026-07-22 and 2026-07-29) removed `mcp.server.fastmcp` and renamed FastMCP to MCPServer. `agent_gate.server` imports FastMCP at module scope, so with `mcp>=1.2` now resolving to 2.x the module no longer imports -- which breaks the shipped `agent-gate` console script for anyone installing the package today. CI surfaced this as a coverage failure rather than a test failure because tests/test_server.py swallowed *any* ImportError from `agent_gate.server` into unittest.SkipTest. The 4 server tests skipped silently, server.py fell from 93% to 11%, and the total dropped 96.67% -> 68.89%, tripping --cov-fail-under=90. No Python code changed on the dependabot branch; the only differing input between the 07-22 pass and the 07-29 fail was mcp 1.28.1 -> 2.0.0. - server.py: import MCPServer on 2.x, fall back to FastMCP on 1.x, so the declared `mcp>=1.2` range is honest again for both majors. - test_server.py: skip only when the `mcp` SDK is genuinely absent. If the SDK is installed, an import failure is a real incompatibility and must fail loudly instead of quietly removing server.py from the coverage denominator. Verified locally with the exact CI command on py3.11: mcp 2.2.0 -> 19 passed, 94.62% mcp 1.30.0 -> 19 passed, 96.77% Coverage threshold unchanged at 90; no tests removed. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Why
Dependabot #7 (actions bumps only) fails the coverage gate at 68.89% against 90. The same branch passed on 2026-07-22 and has failed since 2026-07-29. Diffing those two CI runs: identical Python 3.11.15, pytest 9.1.1, pytest-cov 7.1.0, coverage 7.15.2. The only difference is
mcp1.28.1 -> 2.0.0.mcp 2.0 removed
mcp.server.fastmcpand renamedFastMCPtoMCPServerundermcp.server.mcpserver.agent_gate/server.pystopped importing, andtests/test_server.pyconverted thatImportErrorinto aSkipTest, silently dropping the 4 server tests.server.pywent from 93% to 11% covered with every test green. Thecoveragejob passed because it runscoverage reportwith no--fail-under.This also means the published
agent-gateconsole script has been broken for anyone installing with a currentmcpsince late July, so the fix is to the package, not just to CI.What
agent_gate/server.py: try the 2.x import, fall back toFastMCPon 1.x.MCPServeris drop-in for everything this module uses (positional name,.name,.tool()returning the undecorated function,.run()default stdio). Verifiedlist_tools()and acall_tool('verify_gate', ...)round-trip produce identical output on mcp 1.30.0 and 2.2.0.tests/test_server.py: skip only whenimport mcpitself fails. With the SDK present, a brokenagent_gate.serverimport is now 4 real failures namingModuleNotFoundError, not 4 silent skips. Verified by swapping the oldserver.pyback in against the new test.--cov-fail-under=90untouched, no tests removed. The declaredmcp>=1.2stays true across both majors (mcp.server.fastmcpfirst shipped in 1.2.0).Verification (local, py3.11)
Coverage lands at ~95 rather than the old 97: the two new lines are the 1.x fallback branch, which CI (latest mcp) does not execute. Reviewer follow-ups not included here: a CI matrix leg on
mcp<2to exercise the fallback, one async test throughlist_tools/call_tool, and re-raising when the 2.x import fails for a reason other than the module being absent.🤖 Generated with Claude Code