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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds material context beyond them: only public fields are returned, owner names and numbers are withheld, no sign-in needed, and authenticated calls surface prior unlocks. This tells the agent exactly what it will and will not get, which is the important behavioral caveat for this tool.

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?

Dense but well front-loaded: purpose first, then coverage caveats, then return shape, then the unlock handoff. A few clauses about sign-in state could be tightened, but no sentence is filler.

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?

There is no output schema, and the description compensates by enumerating the returned fields (name, street, postcode, shop/practice line, owner-held flag, unlock cost). Combined with the auth-state note and the unlock handoff, an agent has everything needed to call and interpret results.

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%, so the baseline is 3; the description earns above that by explaining that salon, barber and beauty draw from a single regional list while dental covers independent practices nationwide and accepts a region name. That semantic distinction is not derivable from the enum alone, though 'limit' and postcode formatting are left entirely to the schema.

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?

Opens with a specific verb and resource plus a geographic scope ('Find independent businesses near a town, borough or postcode in England'). It immediately distinguishes itself from unlock by stating owner names never appear here, so an agent can separate it from its sibling without opening either 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?

Explicitly routes follow-up work: 'Pass a result's id to unlock to get them,' and clarifies that no sign-in is required while noting signed-in results add unlock status. It also scopes trade coverage (salon/barber/beauty share one list limited to five cities, dental is England-wide and accepts regions), which helps an agent pick a valid query. No guidance on when to prefer coverage or balance instead, so not a full 5.

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