FastMCP Development Assistant

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

Annotations already declare readOnlyHint=true and openWorldHint=true, indicating this is a safe read operation that may return incomplete data. The description adds value by specifying what the analysis includes (type definition status, recommendations, alternatives), which goes beyond the annotations. However, it doesn't mention behavioral aspects like rate limits, authentication needs, or what 'comprehensive' entails.

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 in Japanese that clearly states the purpose and outputs. It's appropriately sized and front-loaded with the core functionality, with no wasted words or unnecessary elaboration.

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?

For a read-only analysis tool with good annotations (readOnlyHint, openWorldHint) and 100% schema coverage, the description provides adequate context about what the analysis includes. However, with no output schema, the description doesn't explain the format or structure of the analysis results, leaving some ambiguity about what 'comprehensive analysis' returns.

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%, with both parameters clearly documented in the schema. The description doesn't add any parameter-specific information beyond what's in the schema (packageName and version). The baseline score of 3 is appropriate since the schema does the heavy lifting for parameter documentation.

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 clearly states the tool performs 'comprehensive analysis of TypeScript type definitions for specified NPM packages' with specific outputs (type definition status, recommended approaches, alternatives). However, it doesn't explicitly distinguish this analysis tool from sibling tools like 'fetch-npm-types' which presumably fetches type definitions rather than analyzing them.

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?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'fetch-npm-types' or explain scenarios where analysis is needed versus fetching raw type definitions. The context is implied (when you need analysis) but no explicit usage boundaries are provided.

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