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

Annotations already declare readOnly, idempotent and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: ordering (ascending by date), one row per publication day, and that each invocation is billed once — the billing note is valuable and nowhere in structured fields. It stops short of saying what happens when limit truncates the series.

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?

Three short sentences, front-loaded with purpose, followed by ordering and cost — every sentence carries information. The '(PIT)' tag is left unexplained, which is the only minor waste for a reader unfamiliar with the term.

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 should describe the shape of a returned row (what fields a '评分' record contains) — it only says 'the score for each publication date'. Billing, ordering and single-agency scope are covered, so it is adequate but leaves the return payload underspecified.

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 all four parameters including agency_id format and limit bounds are documented in the schema; the description adds only that agency_id scopes to a single agency and that results are date-ordered. It does not clarify start_date/end_date inclusivity or truncation behavior for limit, so baseline 3 is appropriate.

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: returns the historical score trend for one agency_id, one score per publication date, ordered earliest to latest. That is clearly distinguishable from ranking/coverage siblings, but the very close sibling get_agency_pit is never named or contrasted, so an agent must infer the difference between 'history' and 'point-in-time'.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no pointing to get_agency_pit or list_agency_pit_dates as alternatives for a single snapshot or for enumerating valid dates. Only the word '单个' implicitly signals single-agency scope.

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