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

Goes well beyond the annotations by disclosing error semantics (400 unsupported pair, 422 conversion failed), the return behavior, and especially the payment model ($0.02 USDC per call via x402), which an agent cannot infer from readOnlyHint/idempotentHint. This is exactly the kind of context annotations don't carry.

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?

Front-loaded with purpose, then formats, usage, parameters, return, errors, and price in a logical order. The format enumerations are long but essential for a conversion tool; the only mild slack is the compressed multi-clause parameter sentence.

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 correctly states it returns the converted file and adds error codes and pricing. Together with the fully-covered schema, an agent has enough to invoke it correctly; minor gaps like supported size limits per conversion are not critical.

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 schema already documents all four parameters including the url-or-base64 mutual exclusion and the 20 MB limit. The description's restatement of "{url} or {base64}, plus filename (with extension) and to" adds little beyond what structured fields provide, so baseline 3 applies.

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 (Convert) and resource (office documents and images) with an explicit format matrix in both directions. The breadth of the format list clearly distinguishes it from narrower siblings like html_to_pdf, which is a subset of this tool's scope.

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?

"Use when a user or system needs a file in a different format" gives a clear selection condition. It stops short of naming when NOT to use it or routing to the narrower alternatives (e.g. html_to_pdf for HTML), so it lacks explicit exclusions.

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