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

With no annotations, the description carries the full behavioral burden and does well: it discloses cost (1 credit per minute of output), async behavior (long jobs return a job_id, poll with get_job), and result expiry (links expire in 1 hour). It omits permission/auth requirements and any input size or duration limits, which are the remaining gaps.

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?

Four compact sentences, front-loaded with the core action and format list, followed by cost and async/expiry mechanics. Every sentence carries information an agent needs; nothing is redundant with the title.

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 7-parameter tool with no output schema, the description covers the important call-time mechanics (async job_id, polling tool, expiring links) and the format domain. It could go slightly further on what the immediate response contains versus the polled result, but nothing essential is missing.

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 100%, so the baseline is 3, but the description adds real value beyond the schema by grouping the flat format enum into video outputs and audio outputs and by framing trimming/downscaling as the intent behind the timing and height parameters.

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+resource (convert video or audio files between formats) and enumerates the exact output formats, which lets an agent distinguish it from siblings like compress_media, extract_audio, and trim_media without opening the schema.

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?

Clearly signals the scope of the operation ('convert to another format, with optional trimming and downscaling') and tells the agent what to do for long jobs (poll with get_job). It never explicitly names when to prefer a sibling such as extract_audio or compress_media instead, so routing is left partly to inference.

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