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

Annotations only provide readOnlyHint=false and destructiveHint=false, so the description carries the burden of explaining behavior. It discloses the short-lived nature of the link, the need to poll media_upload_status with the token, and the sequencing/dependency on publish. This goes beyond annotations and helps the agent understand the tool's non-trivial behavior, though it doesn't cover failure modes or exact token details.

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?

The description is concise and well-structured: it starts with the core action, then provides the workflow, a caution, and an alternative. Every sentence adds necessary information without fluff, making it efficient and easy to parse.

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, so the description must convey return values and usage context. It mentions the link and the token, explains the follow-up status polling, and differentiates from a sibling tool. It is sufficiently complete for a simple one-parameter tool, though it could mention the lack of a return schema explicitly, but the context is clear.

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 input schema fully describes the only parameter (note) with 100% coverage, so the description doesn't need to add extra parameter details. The description adds no additional semantic value beyond what the schema provides, resulting in a baseline score of 3.

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?

The description clearly states the tool's purpose: asking the person to upload files and returning a short-lived link. It explicitly distinguishes itself from media_from_url, so it's easy to identify when to use this tool.

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?

The description provides explicit usage guidance: use it when the file is on the person's device, and use media_from_url when the file has a public https address. It also explains the full workflow (give link, wait, poll status, then publish), including the caution not to publish before ready.

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