MCP Server Whisper

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

No annotations are provided, so the description carries the full burden. It mentions the >25mb threshold and fallback usage, but lacks critical behavioral details: what compression algorithm is used, whether the original file is preserved or overwritten, what formats are supported, error handling for invalid files, or performance characteristics. For a mutation tool with zero annotation coverage, this is insufficient.

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 two concise sentences with zero waste. The first states the purpose and condition, the second provides usage guidelines. It's front-loaded and efficiently structured.

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 a mutation tool with 3 parameters, 0% schema coverage, no annotations, but an output schema exists, the description is incomplete. It lacks details on parameter semantics, behavioral traits (e.g., file handling, supported formats), and doesn't leverage the output schema to explain return values. The usage guidelines are strong, but other aspects are underdeveloped.

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 0%, so the description must compensate. It only implies the 'max_mb' parameter through the >25mb condition but doesn't explain 'input_file_name' (what formats/paths), 'output_file_name' (default behavior if null), or how parameters interact. The description adds minimal value beyond the bare schema.

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's purpose as compressing audio files, with the specific condition that they must be >25mb. It distinguishes from siblings by focusing on compression rather than transcription, conversion, creation, or listing. However, it doesn't explicitly differentiate from all siblings (e.g., 'convert_audio' might also handle compression).

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 explicit usage guidelines: 'ONLY USE THIS IF THE USER REQUESTS COMPRESSION OR IF OTHER TOOLS FAIL DUE TO FILES BEING TOO LARGE.' This gives clear conditions for when to use this tool versus alternatives, including fallback scenarios.

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