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

With no annotations, the description carries the full load and does so well: it discloses that the URL is unauthenticated because the unguessable id is the capability, that it is therefore safe to hand off, and that it expires roughly one hour after conversion. These are exactly the behavioral facts an agent needs to avoid misuse.

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?

Three tightly written sentences, front-loaded with the return value and mode selection, then closing with the expiry caveat. No sentence is padding.

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?

The tool has no output schema and no annotations, so the description must explain the return (a URL), its auth model, and its lifetime — all of which are present. Nothing an agent needs to call it or use the result correctly 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 coverage is 100%, so the baseline is 3, but the description reinforces the semantics with use-case framing (job_id resolves the converted output of a completed job; file_id addresses a file directly) and implies the either/or constraint. It adds modest value beyond the schema text.

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 ('Returns the download URL of a converted file') and immediately distinguishes its two operating modes — resolving via job_id versus addressing a known file_id. An agent can tell this apart from the sibling get_upload_url 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?

It gives clear selection guidance between the two entry points (job_id for a finished conversion, file_id for a known uid) and advises acting promptly before retention lapses. It stops short of naming or excluding any sibling tool as an alternative.

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