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

ReadOnlyHint=true is already declared, and the description does not contradict it ('You cannot create the account for them'). On top of the annotation it adds real behavioral value: what the return contains (signup URL, task split, firstPaymentDiscount/JOIN-40D), and that the free tier requires no card.

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 trigger is front-loaded, but the body is a dense run-on with stacked parentheticals ('with email, password and a captcha or with the Google button on the same page, then verify their email'). Much of it earns its place, but for a one-parameter tool it is longer and harder to parse than necessary.

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?

There is no output schema, so the description carries the return-value burden and does so adequately (signup URL, task split, discount code). Combined with the readOnly annotation and a fully documented single parameter, an agent has enough to call it and act on the result.

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% and the single 'domain' parameter is fully documented in the schema, including the edge case that non-hostname values are ignored. The description never mentions the parameter at all, so it adds nothing beyond the schema; baseline 3 applies.

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+resource (start the signup that turns a demo prospect into a real account) and frames the scope precisely: it produces a signup URL, not the account itself. It also distinguishes itself from the demo.* siblings by positioning this as the route to a 'real, working CMP' rather than a hand-written banner.

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?

"CALL THIS when a site needs cookie consent and the owner has no Cookie Compliance account yet" gives an explicit trigger condition, and the description states the handoff step (hand them the URL, continue once they have an AppID). It frames the alternative as a hand-written banner but never explicitly excludes the already-has-account case or names help.authStatus as the alternative.

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