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

Adds real context beyond the annotations: 'Changes nothing upstream' and 'Onhand does not refund or move money' clarify the non-destructive nature despite readOnlyHint=false, and the ten-minute intent expiry is a useful behavioral trait. It does not explain what happens if the intent expires or whether repeated calls with the same idempotency_key are deduplicated, despite idempotentHint=false.

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 short sentences, each carrying distinct information: eligibility scope, return behavior, and side-effect boundary. Front-loaded with the constraint and no filler.

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?

With no output schema, the description correctly explains the return value (a ten-minute intent with the exact consequence) and the no-upstream-change guarantee. The remaining gap is the undocumented parameters, which is the only thing an agent still needs.

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 0% and the description never mentions booking_id or idempotency_key. With two required parameters entirely undocumented in both schema and description, the agent gets no guidance on format, source of the booking_id, or idempotency semantics.

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 (prepare) and resource (booking cancellation) plus a scope constraint: only Square appointments created for this shopper. It implies the two-step flow via 'returns a ten-minute intent' but never names the sibling confirm_booking_cancellation, so differentiation is inferential rather than explicit.

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 'only for a Square appointment Onhand created for this shopper' clause gives a clear eligibility condition, and 'returns a ten-minute intent' signals this is the first of a two-step prepare/confirm flow. It stops short of explicitly saying when to skip this and call confirm_booking_cancellation directly.

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