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

Annotations are minimal (all false hints), so the description carries the behavioral burden. It discloses the core behavior: returns an upload_url, requires a PUT, and mandates follow-up with check_file. It could add details about failure modes or auth requirements, but the key workflow is transparent.

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?

Four sentences, no waste. Purpose and usage are front-loaded, and the workflow steps are logically ordered. Every sentence adds value and the structure is easy to follow.

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 multi-step tool, the description covers the entire lifecycle: mint, PUT, check, and handoff to design tools. It also specifies allowed file types and contrasts with the sibling upload_file. Output schema exists, so return values are covered. Nothing critical is missing for an agent to call it correctly.

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% and all params have descriptions. The description reinforces semantics by noting 'same Content-Type' for content_type and 'exact byte size' for size_bytes, adding usage nuance beyond the schema. This justifies a 4 rather than a baseline 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?

Description states a specific verb ('Mint a presigned upload URL') and resource ('photo/logo/PDF'), and distinguishes from sibling upload_file by noting it's preferred for larger files and explicitly forbids base64 encoding into asset_files. This makes the tool's purpose unambiguous.

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?

Explicitly states when to use (anything larger than a small icon), what not to do (do not base64, do not compress), and the full workflow: PUT original bytes, check_file until ready, then pass file_ids to design tools. This leaves no room for misinterpretation.

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