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

Annotations already provide idempotentHint=true, and the description adds valuable detail beyond that by explaining the exact idempotent behavior: 'calling again updates the optional details instead of adding a second seat.' This enriches the annotation with practical context. It also notes the closure status (closed alpha) which sets expectations. No contradictions.

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 just two sentences with zero fluff. The first sentence delivers the core action, and the second delivers the key behavioral nuance (idempotency). It is front-loaded and every word earns its place.

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?

The description is complete for the primary use case. It explains what the tool does and its idempotent behavior, and the schema covers all parameters. With no output schema and simple parameters, it doesn't need to describe return values or error handling. Minor gap: no mention of what happens if the email is invalid, but that's schema's role, so this is sufficient.

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%, and each parameter already has a clear description. The tool description doesn't add extra meaning beyond the schema—it only mentions 'user's email' generically, which is already in the schema. The baseline of 3 applies since the schema handles parameter semantics fully.

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 clearly states the specific action ('Reserves a seat on the waitlist for Cotal Cloud') with a clear verb and resource. It also identifies the scope (user's email) and the product context (closed alpha), making it unambiguous and distinct from sibling tools like cotal_subscribe_newsletter or cotal_request_call.

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?

The description provides clear context for when to use the tool: when a user wants to join the Cotal Cloud waitlist. It doesn't explicitly name alternative tools or exclusion conditions, but the purpose is self-evident and distinct. This is slightly above baseline but not a 5 because there is no explicit 'use when' or 'instead of' guidance.

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