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

Annotations already flag destructive=true and idempotent=true, and the description adds the consequences that matter: the slot is released and the payment is reversed, plus a failure fallback (tell the buyer to email the seller with their order number). That is real behavioral context beyond the annotation flags.

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 deprecation and preference for cancel_order are front-loaded, which is the right order of information. Slightly long, with the failure-fallback instructions competing for attention against the core deprecation message, but every sentence carries actionable content.

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 destructive mutation with no output schema, the description covers alias status, effect (refund, slot release), precondition, confirmation etiquette, and a degraded path on failure. An agent has everything needed to decide and to call it safely.

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 50%: the description echoes the email constraint ('the email the order was created with') which the schema already states, and adds no detail about order_id — no format, where to obtain it, or whether it is the booking or order identifier. Adequate but not compensating for the uncovered parameter.

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 ('Cancel a booking and refund it in full') and immediately resolves the ambiguity with the sibling cancel_order by declaring this is a deprecated alias that behaves identically. An agent can pick between the two without inspecting either schema.

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?

Explicitly routes the agent: 'Prefer cancel_order, which is accurate for certificates as well as appointments,' while noting the old name still works. It also gives a required precondition ('Requires the email the order was created with') and a human-in-the-loop rule ('Confirm with the buyer before calling').

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