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

Annotations give destructiveHint=false and openWorldHint=true but say nothing about side effects, timing, or token lifetime; the description fills that gap by disclosing the email side effect, the 24-hour expiry, single-use semantics, and that no charge or refund occurs. This is exactly the extra context annotations cannot carry.

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?

Four short sentences, front-loaded with the step-1-of-2 framing, then preconditions, then the no-side-effect guarantee, then token lifetime and the handoff. No sentence is redundant.

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?

Output schema exists so return values need not be described, and the description covers the workflow position, prerequisites, side effects, token lifetime, and the next step. Nothing an agent needs to invoke this correctly is missing.

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 both parameters are documented in the schema (guestEmail must match the primary guest, confirmationCode is an 8-char code). The description restates the email-must-match rule and adds no format or syntax detail beyond the schema, so baseline 3 applies.

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?

Names a specific verb and resource (request a cancellation token) and frames itself explicitly as step 1 of a 2-step cancellation flow, which separates it cleanly from the sibling cancel_booking that performs the actual cancellation.

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?

States the precondition (confirmation code plus the matching booking email) and names the follow-up tool that consumes the token, so the agent knows both when to call this and what to call next. The 'nothing is cancelled by this step' clause further clarifies it is the entry point, not the completion.

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