The server defines 2 tools with clear action verbs (run_tests, type_check) and reasonable descriptions (156 - 198 chars, within baseline 34 - 392). However, parameter descriptions are sparse and lack actionable detail, input schemas lack type constraints (enums, min/max), and output format is unstructured plain text rather than typed objects. Tool definitions are explicitly visible in code via ListToolsRequestSchema handler, so inference penalty does not apply. Error handling returns isError: true with text, but lacks recovery guidance. No tool annotations (readOnlyHint, etc.) present despite both tools being read-only. STDIO transport caps protocol score at 50, but definition quality is mid-range due to schema incompleteness and lack of parameter rigor.

• Add min/max length constraints and glob pattern rules to testFiles and files parameters. Example: 'testFiles: Array of file globs relative to projectDir root. Each glob must match .test.ts, .test.js, or .spec.ts files. Max 50 files per call to prevent timeout. E.g. ["src/**/*.test.ts", "tests/unit/*.spec.ts"]'.
• Restructure run_tests and type_check outputs to return structured objects with per-item details. Instead of plain text summary, return { passed: number; failed: number; tests: [{name: string; path: string[]; state: 'passed'|'failed'|'skipped'; duration_ms: number; error?: string}] } and { errors: [{file: string; line: number; col: number; message: string; code?: string}]; total: number }.
• Add tool annotations: include 'readOnlyHint: true' in both tool definitions since they only read project state and do not modify files.
• Improve error messages to include recovery hints. Example: 'Failed to start Vitest: <error>. Ensure vitest is installed (npm install vitest), package.json exists in projectDir, and vitest.config.ts is valid. Try calling with an empty testFiles param to run all tests.'
• Document expected parameter formats in descriptions. Clarify whether testFiles accepts absolute or relative paths, whether glob patterns are supported, and what the projectDir baseline is.
• Define explicit output schema as part of tool registration. Extend ListToolsRequestSchema response to include outputSchema property (or document it in the description) so clients and LLMs know the structure of formatTestResults and formatTypeErrors output.