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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: the price snapshot includes the time it was read and price-book versions, and it explicitly warns that the live price on the model page is authoritative — a data-freshness caveat an agent could not infer from structured fields.

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?

One long but front-loaded sentence: the action and identifier lead, the return inventory follows, and the authoritative-price caveat is last. Dense, but every clause maps to information an agent would otherwise have to discover, so there is little waste despite the run-on structure.

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 it does so thoroughly (URLs/endpoints, prices with timestamps, context window, modalities, limits, links). It is complete enough to call correctly; only the vague 'capability contract' and 'limits' phrasing keeps it from a 5.

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% with a single parameter whose pattern, length bounds, and source-of-truth ('as returned by chinaapi_list_models') are already documented in the schema. The description's 'exact ID' wording reinforces case-sensitivity but adds no syntax or format detail beyond the schema, so 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?

States a specific verb and resource — 'Get one model by its exact ID' — and then enumerates the payload so the agent knows exactly what class of data this returns. It is clearly distinguishable from the sibling chinaapi_list_models (single-record lookup vs. collection listing).

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 'by its exact ID' phrasing plus the schema note that the ID comes 'as returned by chinaapi_list_models' establishes the correct call sequence (list then get). There is no explicit when-not-to-use statement or named alternative for bulk retrieval, so it stops 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.