FastMCP Development Assistant

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

The description adds context about what information is displayed (statistics and settings), which goes beyond the annotations that only indicate read-only operation. However, it doesn't detail behavioral traits like rate limits, error conditions, or output format, which would be helpful given the lack of an output schema.

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 that directly states the tool's function without any unnecessary words. It's appropriately sized and front-loaded, making it easy for an agent to parse quickly.

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 the tool's simplicity (0 parameters, read-only operation) and lack of an output schema, the description is adequate but has gaps. It doesn't explain what specific statistics or settings are returned, which could hinder the agent's understanding of the tool's output, especially without an output schema to compensate.

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?

The tool has 0 parameters with 100% schema description coverage, so the schema fully documents the inputs. The description doesn't need to add parameter information, and it appropriately focuses on the tool's purpose without redundancy, earning a baseline score of 4 for no parameters.

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 states the tool displays statistical information and settings for an NPM-type definition cache, which provides a general purpose. However, it's somewhat vague about what specific statistics or settings are included, and it doesn't clearly differentiate from sibling tools like 'analyze-npm-types' or 'fetch-npm-types' that might also relate to NPM types.

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. The description doesn't mention any context, prerequisites, or exclusions, leaving the agent with no usage instructions beyond the basic purpose.

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