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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: one entry per partner, pickup facts we checked, tracked booking link, and empty list when no partner covers the city. This goes beyond the annotations without contradicting them.

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 description is a single, dense sentence that front-loads the core purpose and then adds the key behavioral details. Every clause earns its place, and the empty-list note is a valuable edge-case disclosure.

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 read-only list tool with an output schema and full schema coverage, the description is nearly complete. It explains the result shape (one entry per partner, empty list) and the verification aspect. It does not detail pagination or sorting, but those are minor given the output schema and annotations.

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 the schema already documents both parameters. The description adds the notion of 'city coverage' but does not add new parameter-level meaning beyond the schema. 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?

The description states a specific verb ('cover'), a resource ('car hire partners'), and a clear scope ('per city'), and it distinguishes itself from siblings by emphasizing verified coverage and tracked booking links. It also clarifies the empty-list behavior, which is a useful semantic detail.

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 description implies when to use it: when you need car hire partners that verifiably cover a city, and it notes the read-only nature. It does not explicitly name alternatives or exclusions, but the sibling list and the 'read-only' qualifier give enough context for an agent to select it appropriately.

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