Code MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full burden. It mentions 'using appropriate test runner' but doesn't disclose behavioral traits like whether it runs tests in isolation, outputs results to console/files, handles errors, requires specific permissions, or has side effects (e.g., modifying files). For a tool with 4 parameters and no annotations, this is a significant gap in transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with no wasted words. It's front-loaded with the core action ('Run tests'), though it could be more structured (e.g., by mentioning key parameters). It earns a 4 for being concise but loses a point for not optimizing clarity in minimal space.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 4 parameters, no annotations, and no output schema, the description is incomplete. It doesn't cover what the tool returns (test results, exit codes), error handling, or dependencies. For a tool that likely executes code and may have complex behavior, this minimal description leaves too many gaps for effective use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters (language, framework, path, pattern). The description adds no meaning beyond the schema—it doesn't explain how parameters interact (e.g., language-framework compatibility), default behaviors, or examples. Baseline 3 is appropriate when schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Run tests using appropriate test runner' states the action (run tests) but is vague about scope and mechanism. It doesn't specify what kind of tests (unit, integration, etc.), what 'appropriate' means, or how it differs from sibling tools like run_command or run_python. The purpose is understandable but lacks specificity and differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., test frameworks installed), when-not-to-use scenarios, or how it compares to sibling tools like run_command for general execution or run_python for Python-specific tasks. The description offers no usage context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.