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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, but the description goes well beyond them: it documents 404 error text, warns that capacity values are historical snapshots and must not be used for inventory math, explains the isComplimentary flag's status/amount semantics, and states that mutations (transfers, cancellations, refunds) are dashboard-only. That is exactly the extra context an agent 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-loaded with the core action, then layered constraints, edge cases, and example utterances. Despite its length, every block carries distinct decision-relevant content (routing, error behavior, snapshot caveat, complimentary semantics, read-only boundary) with no filler.

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?

A read-only single-record fetch with full schema coverage, an output schema, and no nested objects needs little more; the description still covers error behavior and non-obvious field semantics. Nothing an agent needs to call 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%, so both parameters are already documented, and the description's livemode and bookingId guidance largely restates the schema. It adds only marginal framing (e.g., that payment IDs are not retrievable here), so the baseline 3 is appropriate.

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 ('Retrieve a single event booking by ID') and immediately scopes it to the seller's own Checkout Page account. It explicitly distinguishes itself from the two most confusable siblings, list_bookings and list_payments, so an agent can select it without opening a 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 explicit when-to-use routing: use list_bookings to discover an ID by email, name, event title, or order ID, and use list_payments for checkout payments. It also states the when-not case (this tool cannot read payments) and the failure condition (404 if the ID isn't owned by the authenticated seller).

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