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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so safety is covered. The description adds genuine value beyond them by disclosing the payload shape (a full detail record with hours, prices, classes, amenities, offers, plus published third-party services), which matters because there is no output schema. It stops short of noting behavior for an unknown id or missing/unpublished sections.

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?

One front-loaded sentence that leads with the action and scope before the field enumeration. The long comma list of returned fields is dense but each item earns its place as payload disclosure in the absence of an output schema; the trailing 'what can be done through this directory (book, message)' clause is the only slightly loose part.

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 no output schema and a bare input schema, the description does the heavy lifting by telling the agent what comes back and where the id comes from — enough to call the tool correctly. The remaining gap is behavioral edge cases (invalid/unknown id, businesses that publish no services), which an agent would have to discover at runtime.

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 0% for the single 'id' parameter, so the description must carry the meaning — and it partially does by tying the id's provenance to search_businesses's return value. It adds no format, length, or failure-mode detail for the id itself, so it compensates only halfway for the coverage gap.

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 ('Full listing for one business') and immediately enumerates what the listing contains — hours, phone, address, prices, classes, amenities, offers, services. The 'by the id search_businesses returned' clause cleanly separates it from the sibling search_businesses tool, so an agent knows exactly which of the two to reach for.

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?

Usage is clearly implied and partly explicit: call this after search_businesses, passing the id that tool returned, and note that booking/messaging are actions reachable 'through this directory' (pointing at book_appointment / contact_business). There is no explicit when-not or statement about what to do if the id is stale or invalid, so it falls short of a full 5.

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