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

Goes well beyond the annotations by disclosing the credit cost model, the 24-hour free-repeat window, that failed/refused conversions are free, and the 60-minute lifetime of the download link. This is the kind of billing, idempotency and expiry context an agent could not infer from readOnlyHint/destructiveHint alone.

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?

Three dense sentences with no filler: what it does and input limits first, then cost, then the input-source rule and return value. Every clause carries information an agent needs to call it correctly.

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 an 11-parameter, nested-object tool with no output schema, the description covers the input source constraint, the pricing/idempotency model, and the shape of the return (download link plus node/path/color counts). Little an agent needs before calling is missing.

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 the baseline is 3, but the description adds a constraint the schema does not enforce: exactly one of the three input sources. That adds real meaning over the structured fields, though the remaining options (scale, width, palette, background, max_colors) are left entirely to 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 ('Convert a logo image ... to a clean vector') and immediately enumerates supported input formats and size limit. It is clearly distinguishable from the siblings create_upload and upload_logo, which handle getting a file in rather than vectorizing it.

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 mutual-exclusion rule ('Give exactly one of image_url, upload_id or image') is explicit and actionable, and it links upload_id back to create_upload. It stops short of saying when to prefer this tool over upload_logo or when vectorization is inappropriate for a given image, so it falls below a full 5.

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