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

Annotations declare readOnlyHint=false, openWorldHint=true, and destructiveHint=false. The description adds useful behavioral context beyond these: it returns a reservation_id, books as staff would in Zen Planner Studio, defaults to user confirmation per call (which can be disabled), affects other people, and requires a Cotlet API key with app access. It stops short of covering error modes or idempotency.

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 purpose is front-loaded, and most sentences earn their place by covering return value, confirmation behavior, external impact, and auth. The first two sentences are somewhat redundant, both restating the booking action, which slightly reduces conciseness.

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?

For a two-parameter booking tool with annotations and no output schema, the description covers purpose, return value, confirmation behavior, external impact, and auth prerequisite. It omits edge-case behavior such as full-class handling, but the core operational picture is complete enough.

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 schema already explains that class_id comes from list_classes and person_id from list_members. The description adds no further parameter meaning such as format or constraints, so the baseline of 3 is appropriate.

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 states a specific verb and resource: 'Reserve a spot in a class for a member,' and notes it returns a reservation_id. It does not name or compare against sibling tools such as cancel_reservation or check_in_member, so sibling differentiation is implicit rather than explicit, keeping it below 5.

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 gives no when-to-use guidance or alternatives; it only states confirmation defaults and API key requirements. It never says when to choose this tool over related siblings like enroll_in_membership or check_in_member.

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