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

Annotations only say this is a non-read-only, non-destructive, non-open-world write; the description adds the two-phase upload handshake, the 25 MB cap, the allowed MIME types, the owner sign-in requirement, and that the second call triggers parsing. It doesn't cover expiry of the PUT address or failure handling.

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?

Dense and front-loaded: capability, limits, then workflow, then types, then auth. A few fragments ('Guest Logic reads it and returns what was found') are loose, and the allowed-types list partially duplicates the opening sentence, but nothing is padding.

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?

With no output schema the description must sketch the return ('returns what was found'), which it does only vaguely. The core workflow, limits, formats, and auth needs are all present, so an agent can call it correctly, but the shape of the parsed result remains unclear.

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 coverage is 100%, so baseline is 3, but the description earns more by explaining that the four flat properties belong to two distinct calls — filename/content_type/size for the first, document_id for the second. That call-sequencing meaning is absent from the schema.

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 and resource ('Call with filename, content_type and size: you get an address to PUT the file to') and names the accepted file types and size ceiling. This separates it from narrower siblings like set_logo or upload_report, though the differentiation is implicit rather than 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?

Gives clear sequencing: call once with filename/content_type/size, PUT the bytes, then call again with document_id. It also states the authentication prerequisite. It does not say when to prefer a sibling such as add_photo or upload_report instead.

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