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

Beyond the annotations (readOnlyHint, openWorldHint, idempotentHint), the description adds key behavioral traits: per-serial rate limiting (3/hour) to prevent enumeration, live data cross-referencing multiple registries, and aggregation of UK stolen-bike databases. This significantly enhances transparency without contradicting annotations.

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 front-loaded with the purpose and includes an example, rate limit, and live data context. It is compact but contains a minor fluff phrase ('the unique data we own') that doesn't add functional value. Overall, each sentence earns its place except that one, so 4 is fair.

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?

Given the tool's simplicity (one parameter, output schema present, strong annotations), the description is complete: it covers purpose, usage example, rate limiter, live data behavior, and data scope. There are no significant gaps for an agent to invoke it correctly.

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 the single 'serial' parameter is well described ('Frame/serial number (4-50 chars)'). The description adds an example serial format ('WTU123456') but no additional semantic meaning beyond what the schema already provides. Thus 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 clearly states the tool's function: 'Check if a UK bicycle is reported stolen by serial number.' It uses a specific verb ('check') and resource ('UK bicycle'), and the scope (by serial number) distinguishes it from siblings like report_stolen or search tools.

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 provides clear context: use when you need to verify a UK bike's stolen status by serial number, with an explicit example query. It also notes a rate limit. However, it does not explicitly state when not to use this tool or mention alternatives (e.g., report_stolen for reporting), so exclusions are implied rather than stated.

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