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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses internal logic about bookingStartPolicy and maxParticipants. It clarifies that starts remain available until capacity is full, giving agents a precise mental model of the returned time windows. 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 tightly written with five sentences, each contributing new information: the core action, return value, capacity nuance, precondition, and fallback. There is no fluff or repetition, making it efficient for agents to parse.

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?

Without an output schema, the description explains the return type ('time windows') and the factors affecting it (bookingStartPolicy, maxParticipants). It also covers the prerequisite (enabledFeatures) and the alternative action, making the tool self-contained and actionable for an agent.

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?

The input schema already provides detailed descriptions for all three parameters (100% coverage). The description adds domain context (bookingStartPolicy, maxParticipants) but does not add parameter-specific semantics beyond the schema. Baseline 3 is appropriate as the schema carries the 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 uses a specific verb 'Check' and clearly identifies the resource: 'available appointment slots for a specific service at a local business on a given date.' It distinguishes from sibling tools like find_next_available_appointments by emphasizing the fixed date and business, and from book_appointment by focusing on availability only.

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?

The description explicitly states when to call: 'ONLY call this if the business has ''booking'' in its enabledFeatures array.' It also provides a clear alternative: 'If the business doesn't support booking, share their contact info from get_business_info instead.' This is exemplary usage guidance.

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