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

Annotations already declare readOnly, openWorld, and idempotent behavior, and the description complements them with useful behavioral details: explicit refusal for venues not set up for online booking, slot times in the venue's timezone, and the contract with book-appointment. No contradiction with 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 compact and front-loaded: purpose first, then when-to-use, then failure handling, then integration note. Every sentence earns its place and there is no filler or repetition of annotation metadata.

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?

Despite having no output schema, the description tells the agent what to expect on the first call (services and prices) and second call (slots), how to handle refusals, and how results connect to book-appointment. For a three-parameter read-only tool, this is complete enough for safe and correct invocation.

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%, so the schema already documents slug, date, and service_id thoroughly. The description reinforces the two-step usage pattern, but this duplicates the service_id schema note rather than adding substantially new parameter-level meaning.

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 opens with a specific, actionable statement: 'Bookable services and open time slots for a venue on a given date.' This clearly distinguishes check-availability from siblings like get-venue and search-venues, and the WHEN TO USE section reinforces that this is the pre-booking step for book-appointment.

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 states when to use: the user has picked a venue with `is_bookable: true` and wants a time. It also gives the correct call sequence, explains how to handle non-bookable venues by offering the phone number, and notes that returned slot times are exactly what book-appointment expects.

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