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

Annotations already declare a non-read-only, open-world, non-idempotent, non-destructive mutation. The description adds substantial behavioral context beyond that: a two-call OTP flow, intermediate status 'verification_required', verificationId return, 15-minute expiry, 5 attempts, calendar invitation on success, and error handling for taken slots or existing accounts. 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 long but well-structured, with STEP 1 and STEP 2 labels and the critical constraint ('never guess, invent or repeatedly retry codes') highlighted. Most sentences earn their place by covering verification, expiry, retries, and error alternatives. A small amount of repetition with the schema descriptions keeps it from being maximally tight.

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-step, open-world booking tool with 7 parameters and an output schema, the description covers everything an agent needs: sequencing, required inputs per step, OTP rules, error cases, and identity restrictions. Return values are left to the output schema, which is appropriate.

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 carries parameter meanings and constraints. The description still adds value by grouping parameters into step 1 vs step 2, clarifying that step 2 should be called with only verificationId and otp, and reinforcing that email must be the user's own address. That is useful operational framing beyond the schema, though not exhaustive per-parameter detail.

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 precise verb and resource ('Books a free 15-minute initial phone call with the AfAMax team') and immediately frames it as a two-step process. It also names the sibling get_available_appointments as the source of the slot, so an agent can distinguish this from the other appointment/pricing tools without opening schemas.

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?

It gives explicit when-to-use and step-by-step conditions: step 1 only after the user picks a slot from get_available_appointments and confirms name/email, step 2 only with the e-mailed code. It also states when not to proceed (slot taken, existing account email) and the alternative action for each, plus a firm usage restriction ('Only book for the person you are talking to').

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