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

Annotations already mark the read-only, idempotent, non-destructive nature, but the description adds meaningful behavioral context: it is an affiliate link, performs no booking or charge, and requires presenting a disclosure to the user. This goes beyond the structured metadata.

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?

Two short sentences, front-loaded with the core purpose, followed by essential non-booking and disclosure information. Every sentence earns its place with no wasted words.

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?

With an output schema and informative annotations, the description is largely sufficient for a simple two-parameter tool. It covers purpose, side effects, and a required user-facing action. A brief note on when to prefer alternatives would make it fully complete.

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 100%, so the baseline is 3. The description does not add any parameter-specific detail beyond what the schema already documents, so no upward adjustment is warranted.

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 ('Get the Viator checkout URL') plus scope ('for one experience'). The affiliate-link clarification and 'does not book or charge' clearly differentiate it from the get/search experience tools among siblings.

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?

Usage context is implied by 'for one experience' and 'affiliate link' but the description never explicitly names alternatives or states when not to use it. It gives clear context but no exclusions, so it falls short of a 4.

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