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

Goes well beyond the annotations by disclosing a per-serial rate limit (3/hour) to prevent enumeration, the fact that data is live and checked on every call, and the underlying data sources. These are actionable traits an agent cannot infer from readOnlyHint/openWorldHint/idempotentHint.

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?

Front-loads the purpose, then layers data-source, rate-limit, example, and routing details in a logical order. It is slightly long, and the trailing found-bike redirect is tangential to the core call, but every sentence carries information.

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, return values need no explanation, and the description adequately covers the operational constraints (rate limit, live data) and data provenance needed to call and interpret the tool. Nothing essential is missing.

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% (baseline 3), but the description adds a concrete example serial ('WTU123456') and confirms the serial is a frame number, giving format guidance beyond the raw 4-50 char schema constraint.

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 and resource ('Check if a UK bicycle is reported stolen by serial number') with clear scope (UK, serial-based lookup). An agent can immediately distinguish this lookup tool from write-oriented siblings like report_stolen.

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?

Gives clear usage context (checking a serial's theft status) and an explicit exclusion: found-bike users should be routed to the external URL instead. However, it never names the adjacent sibling tool report_stolen, so the when-to-use-this-vs-alternatives routing is incomplete.

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