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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuinely new behavioral context not present in structured fields: a free daily allowance acting as a rate limit and a $0.001 USDC x402 charge beyond it, which affects how an agent should budget calls.

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 short sentences, front-loaded with what the tool returns before the pricing caveat. No filler or repetition, though the pricing sentence, while useful, competes with the more essential purpose statement for the same limited space.

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?

The tool is a single-parameter read with a full output schema and complete annotations, so return values and safety need no further explanation. Purpose and cost model are covered; the only gap is not telling the agent where a valid force id comes from.

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 single parameter's format hint ('metropolitan', see forces) is already in the schema. The description adds no additional parameter meaning, so the baseline of 3 applies.

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?

Names a specific resource (a force) and enumerates what is returned: contact details, website and engagement methods. It is clear this is a single-entity lookup rather than the sibling list tool uk-police__forces, though the description never explicitly says 'single force by id' or names the sibling, so differentiation is only implied.

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?

There is no when-to-use statement, no mention that a force id must first be obtained from uk-police__forces, and no exclusions relative to sibling tools like uk-police__force-officers or uk-police__neighbourhoods. The only usage hint ('see forces') lives in the schema, not the description.

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