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

Annotations already establish the safe read profile (readOnly, idempotent, non-destructive), so the description's real contributions are behavioral: the ranking semantics for accepts_payment ('verified first, then declared, then merely mentioned') and the warning that results are keeper-written cards to be treated as data. That prompt-injection caution is genuinely beyond structured fields.

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-loads purpose and then the filter list in a single dense paragraph with no filler sentences; the only excess is re-listing the full built_with enum, which the schema already enumerates.

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 9-parameter search with no output schema, the description covers the highest-value semantics (ranking, safety, filter combination rules) and gives a rough picture of the return shape. Gaps remain around limit/pagination and the protocols filter, keeping it short of complete.

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 only 44%, and the description compensates by defining combination semantics the schema cannot express: 'all required' for the verified badges and 'any one honoured' for built_with, plus the meaning of each verified badge. It leaves limit, protocols, and specialty semantics undocumented, so it is not complete.

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+resource ('Find listed AI agents') plus the axis of search ('by what you need'), which cleanly separates it from get_agent (single lookup) and register_agent/update_agent (writes). It never names a sibling explicitly, so the differentiation is implicit rather than stated.

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?

Enumerating the filters implies when the tool applies, and 'by what you need' hints at the query-driven use case, but there is no explicit when-to-use/when-not guidance and no routing to alternatives such as list_specialties or get_agent once a result is found.

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