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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint). Beyond that the description adds genuinely useful billing behavior — 5 credits only on a hit, nothing charged for zero or multiple matches — and the disambiguation return path. It stops short of richer operational detail (latency, rate limits, what fields the candidate list contains).

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 the return value, then usage triggers, then exclusions, then cost — a sensible ordering with no filler. It is on the long side for three parameters, but nearly every sentence carries a distinct fact.

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?

No output schema exists, so the description carries the return-value burden and does so ('you get back the person, their current role, and the ways to contact them'), plus costs and the ambiguity branch. An agent has everything needed to call it and interpret the result.

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 baseline is 3, and the description earns one more by explaining the name-vs-employer interplay ('add their employer if the name is a common one') and the person_id lock-in flow implied by 'pick one and ask again' after disambiguation.

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?

Opens with a specific verb and resource: 'How to reach one person: their email address, phone number..., and their profile links.' It also explicitly carves itself out from the WHO-to-contact siblings ('this looks up somebody you can already name'), so an agent can separate it from find_buyers_now without opening a 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 concrete triggering utterances ('how do I get hold of her', 'find his email'), an explicit exclusion ('Do not use it to find out WHO to contact'), and the fallback workflow for ambiguous names (get candidate list, pick one, ask again).

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