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

readOnlyHint=true already tells the agent this is a safe read; the description adds auth requirement (登录), ordering (join time descending), the 60-item ceiling, and the crucial population filter that only fully onboarded users are returned. It also explains the meaning of the inPool field, which carries extra weight because no output schema exists.

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?

Core purpose and ordering rule are front-loaded before the workflow arrows, and every clause carries information. The arrow-chain notation is dense and slightly harder to parse than prose, but nothing is padding.

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 one-parameter read tool with no output schema, the description covers auth, ordering, result cap, population filter and one return field. It stops short of describing the rest of each record's payload (names, contacts, complementary attributes), which an agent would only learn by calling it.

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?

With a single parameter at 100% schema description coverage, the schema already documents limit's default, min and max. The description's "最多 60" merely echoes the schema's hard cap, so no meaning is added beyond structured fields — baseline 3 applies.

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?

"刚入驻的人，按入驻时间倒序，最多 60 个" states the exact resource, the sort order and the cap in one clause. It is unmistakably distinct from sibling list_broker_leads, which returns the existing pool rather than newly onboarded people.

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 spells out an explicit downstream chain (list → pick complementary candidates → collect_broker_leads(userIds) → scan_broker_matches) and names the 'check every morning' use case that triggers it. It also gives a negative rule — skip anyone with inPool=true so leads aren't collected twice — which is exactly the kind of when-not guidance most definitions omit.

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