search_all

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

With no annotations, the description carries the burden and does useful work: it discloses the aggregation behavior (results side by side), the ordering (sorted by price), and importantly the partial-failure semantics ('a site that fails is reported without failing the other'). It does not mention rate limits or whether results are cached/live, but the failure mode disclosure is the high-value piece.

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 that are front-loaded with the core purpose, then return shape, then failure handling. No filler or repetition of schema content.

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?

There is no output schema, so the description must convey the return shape, and it does: per-site result groups, price ordering, and degradation on failure. What each result entry contains (year, mileage, price, link) is left unspecified, which is the only notable gap.

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 100%, so every one of the 9 params is already documented with examples and defaults. The description only adds that the 'same filters' apply to both sites, which is a minor semantic addition; 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 (search) and resource (CarMax + Carvana inventory) and makes the combined scope explicit with 'at once,' which cleanly differentiates it from the sibling single-site tools carmax_search_inventory and carvana_search_inventory.

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 phrase 'CarMax and Carvana at once' clearly signals the situation that selects this tool over the sibling single-site searches. It stops short of explicitly saying 'use the per-site tools when you only need one source,' so there are no stated exclusions.

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