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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds two things annotations cannot: that the call '共用查询计次' (shares the query quota/count), which is real cost information, and that it does not infer transaction price, inventory, or fair valuation, which bounds what the results mean. It does not describe the response shape, but the behavioral additions are substantive.

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?

A single compact sentence with the comparison target stated first and the caveats after, so it is front-loaded and wastes nothing. The compression costs a little clarity, since '共用查询计次' is terse enough to be ambiguous about exactly what quota is consumed.

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 tool with a nested sixteen-field query object and no output schema, the description covers scope, cost, and output boundaries but says nothing about what a comparison result actually contains (per-record deltas? aggregates? ranking?). It is adequate to decide whether to call the tool, but not to anticipate the response.

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 effectively near zero across a nested query object with roughly sixteen filter fields, so the description has to compensate. It does clarify the highest-value item, that offered_price_fen is the user's price in fen, and implies the query object reuses the same query semantics as the sibling search. The many optional filters (time_basis, max_age_days, mileage and price ranges, limit) get no explanation beyond their names, leaving most of the schema opaque.

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: compare the user's offered price (in fen) against per-record entries from the same query. That is more precise than a tautology and tells an agent this is a benchmarking/comparison operation rather than a search. It stops short of naming how it differs from siblings like search_quotes or review_quote_source, so differentiation is left to inference.

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?

Usage is only implied: you call it when you have a user's offered price and want to see how it stacks up against comparable records. The clause '不推算成交价、库存或公允估值' functions as a partial exclusion, telling the agent not to come here for valuation or inventory questions, which pushes it above a pure 2. There is still no explicit when-to-use versus search_quotes or calculate_purchase_budget.

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