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

The description only says 'get a presigned URL' and gives no insight into side effects such as creating an upload session, URL expiration, or the need to call media_upload_finish afterwards. Annotations are all false, providing no safety profile, so the description carries the burden and fails to disclose the state-changing nature of initiating an upload.

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?

A single sentence that is front-loaded with the core action and includes a high-value qualifier. No filler or redundancy; the title and description align well.

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?

Despite having an output schema, the description does not explain the expected workflow: how to use the returned presigned URL, whether to follow up with media_upload_finish, or why this differs from media_upload_file. This is a meaningful gap for an upload-start tool, making the description incomplete.

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 parameters are already fully documented. The description adds no additional parameter semantics beyond implying 'large files', earning the 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 uses a specific verb and resource: 'Get a presigned URL for direct file upload', which clearly states the tool's function. The parenthetical 'for large files' distinguishes it from sibling upload tools like media_upload_file.

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 phrase 'for large files' provides clear context for when to use this tool, implying it is intended for direct/large uploads. However, it does not explicitly name alternatives or establish exclusion criteria (e.g., 'for small files use media_upload_file').

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