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

Annotations already declare readOnlyHint=true, so the description doesn't need to re-establish that this is a safe read. It adds useful return-content detail (exact names, types, and allowed values) and ordering guidance, but it does not go into deeper behavioral traits like error conditions or how format pairing affects results.

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?

Two sentences with no wasted words: the first front-loads what the tool returns, and the second gives a crisp call-timing instruction. The examples make the purpose concrete without bloat.

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?

With a complete schema and no output schema, the description adequately covers what the tool returns (exact names, types, and allowed values) and how to use the result. The agent knows why, when, and how to 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?

Schema coverage is 100%, and both input_format and output_format already have descriptive text and examples. The description adds no new parameter-level constraints or syntax beyond restating that these refer to source and target formats.

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 a clear verb and resource: it lists the settings a given conversion accepts, with concrete examples like resize, quality, codecs, bitrate, trim, and crop. This distinguishes it from sibling tools like convert (which performs conversion) and list_formats (which lists formats).

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 explicitly says to call this before convert whenever the user asks for anything beyond a plain format change, and to pass the returned options into convert. It gives clear timing and a condition, though it does not explicitly contrast itself with list_formats or state when not to call it.

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