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

Annotations already declare destructiveHint=true and openWorldHint=true, but the description adds real context beyond them: a preview-then-confirm two-step, an outbound email to the client, and the clarification that no money moves through the assistant (refunds/fees applied by Appty, client pays remainder on Appty). That is exactly the added behavioral context a mutation tool needs.

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?

Front-loads the action, then the confirm gate, then the money caveats, so the most important facts come first. The last three sentences all orbit the same 'Appty handles money' point and could be tightened into one without losing meaning.

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 destructive, open-world tool with no output schema, the description covers the safety-critical items: the preview requirement, the client email side effect, and where money is handled. It leaves open what the preview contains and what 'reason' is used for, which is a modest gap.

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 only 33%: confirm is thoroughly documented in the schema (including the string "true" edge case) and the description merely restates that gate, while 'reason' (maxLength 500) is explained in neither place. With low coverage the description should compensate for the undocumented parameters and it does not.

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 one booking') plus the governing policy and a concrete side effect ('email the client'). This is unmistakably distinct from siblings like reschedule_booking, book_session, and list_bookings, so an agent can route without opening any 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?

Gives an explicit operational gate: it 'returns a preview first and only acts when confirm=true', which tells the agent exactly how to sequence the call. It stops short of naming when not to use it or pointing to an alternative tool (e.g. reschedule_booking for a date change).

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