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

Annotations already cover readOnlyHint, idempotentHint, and non-destructive nature. The description adds operational behavior: it returns info rather than uploading, and gives explicit error-handling guidance (do not retry, use File Upload Widget). This is valuable context beyond the annotations and does not contradict them.

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, with the primary purpose front-loaded in the first sentence. The second sentence adds critical usage constraints (fallback behavior) without redundancy. Every sentence earns its place, and the overall length is appropriate for the information density.

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 simple info tool with one parameter and an output schema, the description covers all necessary aspects: what it returns, when to use it, and how to handle failures. The output schema handles return value details, so the description need not elaborate. It is complete for an agent to correctly select and invoke the tool.

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% and the parameter task_type is fully described in the schema. The description mentions file types (JPEG, PNG, MP4) but that is about upload content, not the task_type parameter itself. It does not add additional meaning to the parameter beyond what the schema provides, so baseline 3 is appropriate.

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 'Returns the upload API endpoint and example request/response' for specific file types (JPEG, PNG, MP4), which is a precise verb+resource. It distinguishes itself from actual upload tools by focusing on providing information, not performing the upload, and the file types are explicit.

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 explicitly states 'Use when the user wants to upload an image/video via the API' and provides a clear fallback: 'If upload cannot be completed for any reason... Immediately use the File Upload Widget instead. Do not ask the user for a public URL.' This gives both when to use and when not to, naming an alternative tool.

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