List models of a make

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

Annotations already declare readOnly/idempotent/non-destructive, so the burden is lower, yet the description adds two things not in structured data: the call is free and consumes no quota, and the `data` field is untrusted listing text that must not be followed as instructions. Missing only minor traits like result-size behavior, which the limit parameter largely implies.

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?

The purpose and ordering constraint are front-loaded in the first clause, followed by the source list and the two operational notes. Dense but every clause carries information; the security note is slightly bolted-on but justified for untrusted data.

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 an output schema present, the description needn't document return shape, and annotations cover the safety profile. Combined with the quota cost and untrusted-content warning, an agent has enough to call this correctly; only a note on truncation or empty results is absent.

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% and all four parameters carry descriptions, including the market-to-source mapping and the limit default/max, so the baseline is 3. The description adds only the market abbreviation glosses and the notion that returned names are the accepted spellings, which is output semantics rather than new parameter meaning.

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?

Names a specific resource ('Model families of one make in one market') with a stated ordering ('most frequent first') and enumerates the per-market sources (Encar/kr, Che168/cn, Copart+IAAI/us). That scoping cleanly separates it from list_brands, which the schema references by contrast.

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?

States the downstream workflow explicitly: 'These are the spellings search_cars understands,' telling the agent these results feed search_cars. Also flags 'Free, spends no quota,' which guides selection against quota-consuming siblings. No explicit when-not-to-use condition, keeping it 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.