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

Annotations already indicate read-only, non-destructive behavior. The description adds essential context beyond annotations by disclosing the data source limitation: 'Data comes from USPTO records, so it is only available for marks with a USPTO record — it does not query WIPO/EUIPO live.' This is a critical behavioral trait.

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 well-structured and front-loaded with the core purpose, followed by usage guidance and a caveat. Every sentence adds value with no redundancy.

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?

There is no output schema, so the description carries the burden of explaining return values. It does so in detail, listing IR number, date, status, renewal, 66(a) extension, Madrid maintenance, and foreign applications/registrations with fields. Combined with the data source caveat, it is complete for a complex 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% since serial_number is described as 'USPTO serial number'. The description restates 'by serial number' but adds no new parameter semantics or format details. 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's function: 'Get the international / foreign footprint of a U.S. trademark by serial number' and enumerates specific data elements (IR number, date, status, renewal, 66(a) extension, etc.). This distinguishes it from sibling tools, none of which focus on international/Madrid filings.

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 description explicitly says 'Use this for ANY question about a mark's foreign, international, Madrid Protocol, WIPO, or EUIPO registrations,' and also provides a when-not-to-use caveat: 'it does not query WIPO/EUIPO live.' This gives clear usage direction and exclusions.

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