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

Annotations already declare readOnlyHint=true and openWorldHint=false, yet the description adds real value: a 1-hour TTL, capability semantics ('do not share it outside the organization'), and cross-organization refusal. It omits permission/auth details and rate-limit behavior, so not quite a 5.

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 tight sentences, front-loaded with the core action and TTL, then sourcing, then security constraint. No filler.

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 one-parameter, low-complexity tool with no output schema, the description covers what is produced, its lifetime, how to obtain the input, and the key constraint. Nothing needed to call it 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?

With 100% schema description coverage on a single parameter, the schema already documents fileId and its sources; the description largely restates the same provenance. Baseline 3 is appropriate since the schema does the heavy lifting.

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 precise verb and resource ('Mint a short-lived signed download URL for a file') plus the org scope. An agent can distinguish it from sibling URL tools such as get_job_result_asset_url and create_audio_upload_url without opening a 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?

Tells the caller where to source fileId (list_files or a completed job's output, with concrete paths like audio_redaction.redactedAudio.fileId) and when a call is refused. It stops short of explicitly contrasting with the similar sibling get_job_result_asset_url, so routing between the two still requires inference.

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