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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states 'One email, no spam; they can unsubscribe from any mail,' which informs the agent of side effects and user control. It also clarifies that `confirmed` attests to explicit consent in the session, which is a key behavioral constraint. It doesn't mention error handling or idempotency, but for a simple waitlist join this is acceptable.

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 two sentences with no filler. It front-loads the core action and then immediately states the critical precondition. Every phrase earns its place: the paid-tier context, the 'ONLY' condition, and the one-email guarantee. It is well-structured and easy to parse.

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 simple tool with no output schema, the description covers the essential context: what it does, when to call, and key behavioral traits. It doesn't explain what happens after joining (e.g., confirmation email), but that's not required without an output schema. It could mention idempotency, but the conditionality makes it sufficiently 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 description coverage is 100%, so each parameter is already documented. The description reinforces the meaning of `confirmed` ('attests to that') but adds little beyond the schema's 'True only if the founder explicitly agreed to join, in this session.' The optional `product_url` is not elaborated further. Per the rubric, when schema coverage is high, baseline is 3, and the description doesn't add significant new semantics.

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 action: 'Put the founder on the marketinque waitlist for a project.' It specifies the resource (waitlist) and adds context about what the waitlist includes (paid tier). This is distinct from the sibling tools, which are all get/list operations, so the purpose is unambiguous and not a tautology.

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 gives an explicit condition: 'Call ONLY after the founder gave you their email and said yes in this session.' This provides a clear when-to-use rule and implies when not to use it. It doesn't explicitly name alternatives, but the sibling set makes it obvious this is the only write tool. The 'ONLY' plus the session consent requirement is strong guidance.

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