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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real behavioral context beyond that: which fields come back (address, phone, hours) and the conditional that distance is only populated for ZIP-driven searches. It stops short of noting result cap or pagination, which the schema covers instead.

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?

Two sentences, no filler: capability and scope first, routing guidance second. Every clause earns its place and the most decision-relevant information (what it searches, what it returns) is front-loaded.

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, full annotation coverage, and 100% schema description coverage, the description only needs to add routing and scope, which it does. The one residual gap is that it doesn't state that a ZIP search sorts by live geo-distance while a keyword search does not sort by distance, though the schema's zip description partially carries this.

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%, and the schema already documents zip precedence over keyword, the take default of 10, and the distance_miles side effect. The description's mention of 'ZIP code or keyword' and distance-for-ZIP only restates that. Baseline 3 is correct when the schema carries the parameter burden.

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 ('physical CarMax store location records') plus the query dimensions (ZIP code or keyword), and explicitly distinguishes itself from two named siblings. An agent can route between carmax_stores, carmax_store, and carmax_search without opening any schema.

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 second sentence names both alternatives and the condition that selects each: carmax_store for a single location's details, carmax_search for vehicles. This leaves nothing to inference about when to pick this tool.

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