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

With no annotations provided, the description fully carries the behavioral burden. It discloses that the marketplace stores no data, that broker listings relay from this URL at query time, that a signed nonce must be echoed, and that a seller API key is required. This provides rich, safety-relevant behavior beyond the schema.

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 focused sentences, each carrying essential information: purpose, data-flow behavior, and requirements. No filler or repetition. The most critical information is front-loaded.

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?

The tool is moderately complex with 3 parameters and no output schema. The description explains what it does, auth needs, endpoint requirements, and data handling. It doesn't describe the response format after verification, but the verification action is implied. Given the absence of output schema, a brief note on return value would improve completeness, but the description still covers essential operational context.

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 descriptions are already clear. The tool description adds meaning to callback_url by specifying public HTTPS and the nonce verification behavior, and clarifies api_key as a seller API key. This enriches parameter understanding beyond the raw 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?

The description explicitly states the action ('Register and verify') and the target resource ('BROKER delivery endpoint'), clearly distinguishing it from sibling tools like register_agent or become_seller. It goes further to explain the data relay semantics, making 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?

The description gives clear context for when this tool is relevant: setting up a broker endpoint for data relay. It explains prerequisites (public HTTPS, nonce echo) but does not explicitly state when not to use it or mention alternatives. This is clear situational guidance without explicit exclusions.

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