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

With no annotations, the description carries the full behavioral burden. It only discloses that the operation is offline; it does not mention input edge cases (e.g., leading dots, case sensitivity), error behavior, or what happens when an extension is unknown. This is minimal transparency for a tool with no annotation support.

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 one compact, front-loaded line with no filler. It earns its place by conveying the core mapping and the offline characteristic, though it could carry slightly more useful detail without becoming bloated.

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 very simple one-parameter tool with an output schema available, the description is nearly adequate but still missing input formatting details and example usage. An agent could likely guess the intent, but would benefit from clarification on accepted extension syntax.

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 weakly signals that the single parameter 'q' is a file extension, but it does not specify expected format, examples, or whether an empty default has special meaning. This is insufficient for reliable parameter construction.

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 uses a clear mapping arrow, 'File extension → MIME type', which states exactly what the tool does. It identifies the resource type (file extension) and the result (MIME type), though it lacks an explicit verb and does not explicitly distinguish itself from sibling conversion/lookup tools.

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 given about when to use this tool over alternatives, such as format converters or online MIME lookups. The 'offline' tag hints at one context but is not developed enough to guide selection among the many sibling tools.

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