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

Annotations already declare readOnlyHint and idempotentHint, but the description adds critical specifics: 'creates nothing until the customer opens it' and 'Nothing is held or booked until checkout is completed.' It also discloses that dog crossing fees are not included in the quote and that missing choices return a reason. This goes beyond the annotation safety profile to explain exact non-effects and error behavior.

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?

The description is concise and front-loaded: it opens with the core purpose, immediately clarifies non-creation behavior, gives usage timing, and then error handling. Each sentence adds distinct value—no fluff or repetition. It is structured logically, moving from what it does to when to use it to what happens on failure.

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?

Given the tool's complexity (14 parameters, 3 required), the description covers all essential workflow aspects: what it prepares, what it returns (live total, signed prefill link), when to call, what happens with missing/unavailable choices, and that nothing is held until checkout. The schema handles parameter-level details, so the description focuses on the overall flow, making it complete for correct invocation.

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% – every parameter has a detailed description in the input schema. The tool description does not add extra meaning to any parameter; it only references overall context like GCL booking_option and crossing, which are already described in the schema. Baseline 3 applies because the schema carries the full semantic load.

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?

The description states a precise action (prepare a confirmed trip), the exact resources involved (swims, accommodation, GCL booking_option, crossing), and the destination (Angling Lines review page). It distinguishes itself from siblings like get_quote (quotes) and list_swims/list_crossings (lookups) by focusing on preparation rather than retrieval or quoting.

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 states when to call: 'Call after the customer confirms the venue, Saturday date, party and choices.' It also provides an alternative path when choices are missing/unavailable: resolve in chat with list_swims/list_crossings, and notes GCL can be booked through chat. This gives clear timing and fallback guidance.

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