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

Annotations already flag destructiveHint=true and openWorldHint=true, so the safety profile is partly carried. The description adds real value beyond them by disclosing side effects annotations cannot express: confirming or cancelling triggers a customer email, and cancellation requires owner approval. It stops short of saying whether the change is reversible or what the call returns.

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, front-loaded with the action and ref format, then side effects, then the safety precondition. Nothing is redundant and no sentence needs a second read.

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 mutation with no output schema, the description covers the actions, identifier format, notification side effects, and the approval precondition. It could still say what the response contains (e.g. the updated booking) and whether repeat calls are safe, but the essentials for correct invocation are present.

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 only 50%, so the description has to carry weight, and it does: it maps the status values to human actions and supplies a concrete ref format example. The 'note' parameter's dual role (internal note also surfaced to the customer on cancellation) is documented in the schema rather than the description, leaving a small gap.

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 set (confirm, cancel, no-show, completed) on a specific resource (a booking identified by ref), plus a concrete ref format example (B7KX2M9Q). It does not, however, differentiate itself from the sibling 'set_booking', which an agent could easily confuse with this mutation.

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 clear context for when to reach for this tool (changing a booking's status) and an explicit precondition: 'Ask the owner before cancelling.' It omits routing guidance against the sibling 'set_booking', so the agent has no stated rule for choosing between the two.

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