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

Beyond the annotations, the description discloses important behavior: case-insensitive exact matching, up to 5 results because numbers can repeat across jurisdictions, a partial-match fallback signaled by the `match` field, date-window limiting through `account_window_from`, and missing owner/applicant fields in results. This is substantial behavioral context not present in the annotations.

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 front-loaded with the core purpose and then adds tightly relevant details about matching, result limits, fallback behavior, date windows, and omitted fields. It is dense but every clause earns its place and there is no filler.

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 still explains the result shape sufficiently: up to 5 permits, a `match` field for partial results, `account_window_from` behavior, and which fields are absent. An agent has enough information to invoke and interpret this lookup tool correctly.

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 three parameters. The description still adds meaning by explaining that city/state disambiguate duplicate numbers and that permit_number is matched exactly while ignoring case, plus the fallback behavior tied to location parameters.

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 states a specific verb and resource: looking up a permit by the jurisdiction-assigned permit number, optionally narrowed by city and state. It clearly implies an exact-number lookup rather than a broad search, but it does not explicitly name or differentiate itself from the sibling search_permits tool.

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?

It explains when to add city or state to disambiguate duplicate permit numbers across jurisdictions, and it describes the partial-match fallback when no exact match exists. It does not explicitly say when to use this tool versus search_permits or other sibling tools, so it provides clear context but no exclusions or alternative routing.

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