Compliance grade
mcptest compliance run scores a server against the mcptest compliance corpus, a fixed set of checks covering the MCP wire protocol, error handling, schema conformance, and the well-behaved-server checks described in compliance baseline. The headline of that score is a single letter grade.
Grade bands
| Grade | Meaning |
|---|---|
| A+ | All corpus checks pass, including the optional ones. |
| A | All required checks pass; some optional checks may fail. |
| B | One or two non-critical failures. |
| C | A handful of failures, mostly non-critical. |
| D | Multiple failures, some of which block real-world use. |
| F | The server does not pass basic protocol conformance. |
The grade derives from the corpus result set. Required checks set the floor: any required failure caps the grade below A, and a failed basic protocol-conformance check grades F regardless of how many other checks pass. The optional checks separate A from A+.
Emit the grade
mcptest compliance run --config compliance.ymlThe default output is color-tinted text with the grade on the first line. --format md, --format json, and --format html render the same score envelope for a CI summary, a machine consumer, or a self-contained report.
Gate on it
Pair the grade with the compliance score delta gate to fail CI when a change drops the overall letter grade or the pass rate, and with the compliance baseline to hold known, accepted failures stable so only new regressions break the build.