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

Annotations only supply destructiveHint=true; the description adds the critical operational fact that this write takes no payment by default, that it can be dry-run via test:true, and that reversal is done 'from the Mindbody front desk' rather than through the API — a genuinely useful irreversibility signal. It omits auth/permission requirements and any rate-limit context.

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?

Three tight sentences, front-loaded with the primary action and scope, then payment semantics, then undo/dry-run behavior. No filler; the endpoint reference is compact.

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 7-parameter mutation tool with no output schema, it covers the key unknowns an agent needs: payment defaults, dry-run, and the absence of an API-side undo. Remaining gaps (auth requirements, response shape, behavior when the class is full) are modest.

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, but the description adds default-state semantics not present in the schema (no pricing option needed unless require_payment is set) and frames test:true as a dry run. It does not explain waitlist/send_email/client_service_id interactions beyond what the schema already says.

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 ('Book a client into a class') and immediately extends scope to the waiting list. It is clearly distinguishable from siblings like mindbody_add_appointment and mindbody_add_client.

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?

Explains the default payment behavior, how to opt into requiring a pricing option, and that test:true performs a dry run. It stops short of explicitly contrasting when to use this versus mindbody_add_appointment, so it is clear context without full alternative routing.

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