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

Annotations only say readOnlyHint=false, destructiveHint=false, openWorldHint=true. The description goes well beyond: it discloses the side effect (emails a token to the booking address), the token's lifecycle (single-use, expires in 24 hours), and explicitly scopes the blast radius ('nothing is cancelled, charged or refunded'). That is exactly the extra context annotations cannot convey.

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 sentences, front-loaded with the step position, then the mechanism, then the constraints and the handoff. No sentence is redundant and none could be dropped without losing information.

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. The description still covers sequencing, the real-world side effect, token expiry and single-use, and the handoff to cancel_booking — everything an agent needs to call this correctly and to explain the outcome to a user.

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 documents both parameters, including the 'must match the booking primary guest email' constraint. The description restates that the email must be the one on the booking but adds no syntax or format detail beyond the schema. 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 Cancellation Link'), states its position in a two-step flow, and distinguishes itself from the sibling that finishes the job (cancel_booking). An agent can tell exactly what this tool does without opening the 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 says this is step 1 of 2, names cancel_booking as the step that 'completes the cancellation with it', and pre-empts the most likely false expectation by stating nothing is cancelled, charged, or refunded. When-to-use and when-not-to-use are both covered.

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