lookup_mime_type

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

The only behavioral disclosure is the cost: 'Costs $0.001 USDC via x402.' No information is provided about side effects, return format, error conditions, or any operational behavior. With no annotations, the description carries the full burden, and it only partially satisfies it by mentioning the fee.

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 short and front-loaded, but the first sentence 'lookup mime type' is redundant with the tool name. The second sentence about cost is useful. There is no unnecessary elaboration, but the redundancy prevents a higher score.

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 has no annotations, no output schema, and a generic params object, the description should explain the tool's purpose, inputs, and output. It only provides a name restatement and cost, leaving the tool poorly contextualized among its many siblings. This is insufficient for an agent to confidently select and invoke it.

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 input schema defines a single generic 'params' object with no described properties, and the description does not explain what parameters the tool expects. The schema description coverage is technically 100% but only because the wrapper parameter has a generic description. The tool name suggests it needs a MIME type or file extension, but no such guidance is given, leaving an agent unable to construct a valid call.

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 'lookup mime type' is essentially a restatement of the tool name, providing no additional detail about the specific function or scope. It does not distinguish itself from sibling tools like lookup_html_entity or lookup_http_code, only categorizing itself as an 'Other Utilities tool.' This is a tautology rather than a clear purpose statement.

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 gives no guidance on when to use this tool versus alternatives. It does not mention the type of input required (e.g., file extension, MIME type) or any use cases. The sibling list includes many other lookup tools, but there is no differentiation or contextual advice.

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