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

With no annotations, the description carries the full behavioral burden, and it does disclose valuable non-obvious behavior: gif output is truncated to the first 30 seconds at 480 px wide, and the audio formats extract the soundtrack. It says nothing about whether the url must be remote or local, size/duration limits for non-gif formats, whether the job is synchronous, or where the converted file goes.

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 tight clauses: the core action is front-loaded, then format-specific behavior is packed into one parenthetical with zero filler. Nothing is redundant, though the parenthetical is dense enough that a reader must parse it carefully.

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 two-parameter tool with no annotations and no output schema, the description should cover both the input source and the result. It thoroughly covers format behavior but leaves the required `url` parameter and the return value (file location, duration, async job handle) entirely undefined.

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 0% and neither parameter has a title-level description, so the description must compensate. It does this well for `format` by enumerating all six accepted values and their per-value semantics, but `url` receives no explanation at all (accepted schemes, local vs remote, max size), and the values are not encoded as a schema enum.

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?

States a specific verb and resource ("Convert media to another format") and enumerates the target formats, so an agent can tell it apart from siblings like video_resize or video_trim. It stops short of naming a sibling or stating the source-media scope (video only? audio only?), which keeps it from a 5.

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?

There is no explicit when-to-use guidance, no prerequisites, and no routing to alternatives such as video_trim or video_extract_frames for the underlying operations the formats imply. The format list only weakly implies usage context.

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