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

Annotations only cover the safety profile (readOnlyHint=false, destructiveHint=false); the description adds substantial behavioral context beyond that: 15-minute expiry, 512 MB cap, PUT-only raw-bytes semantics, and MP4/MOV restriction. It omits auth requirements, but discloses the key operational constraints.

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?

Front-loaded with the core purpose and packed with actionable detail; the curl example and size/format constraints all earn their place. It is a dense single paragraph but has minimal waste.

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 tool that returns a signed URL and upload_id with no output schema, the description fully covers the end-to-end flow: how to upload, time/size/format limits, and where to pass upload_id next. Nothing needed to invoke 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?

The tool takes zero input parameters, so the schema carries no semantics to document and baseline 4 applies. The description usefully clarifies the returned upload_url and upload_id and how to consume them, though these are outputs rather than inputs.

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: "Mint a short-lived signed URL for uploading a video directly." It distinguishes itself from siblings by naming create-submission-tool as the next step and form_upload_url as the multipart alternative, so an agent can tell it apart 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?

Explicit when-to-use ("when you do not have a public video_url") and when-not ("Do not POST or send multipart to upload_url"), plus a named alternative (form_upload_url for POST/multipart under 100 MB). The full workflow is spelled out with no inference required.

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