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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds real behavior: it searches every brand the user holds, each result carries a brand field, and pool units with no date are silently excluded when on_date is set. It does not mention result caps or pagination, so not a full 5.

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?

Four compact sentences, front-loaded with the lookup keys and following with result shape, the on_date narrowing rule, and the multi-match instruction. Each sentence carries information, though the pool/date exclusion is stated twice (once in prose, once via the schema) causing minor 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?

With no output schema, the description carries the burden of describing returns and does so: a single match yields the crew and its units, the brand is included, and ambiguous matches require user clarification. Nothing an agent needs to call this correctly is missing.

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%, so both parameters are already documented, and the description largely restates that on_date narrows to one day and pool units are excluded. It adds no format or syntax detail beyond the schema, which is the expected baseline when the schema does the heavy lifting.

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 (look up) and resource (a project), enumerates the three lookup keys, and defines the domain object ('a project groups jobs (its units) under a shared crew and window'). An agent can distinguish it from find_customer, find_resource, and the generic search siblings without opening any schema.

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?

Gives clear operating context: use on_date to narrow units to a single day, and 'when several projects match, ask the user which they mean' – an explicit disambiguation instruction that many definitions omit. It never names a competing sibling tool or states when NOT to use this one, so it falls short of a 5.

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