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

Beyond the annotations, the description adds real behavioral context: the challenge-publishing requirement for new domains, the asymmetry between owned and new domains, the refusal behavior for restricted credentials, and an explicit permission requirement. These are meaningful for safe invocation and are not present in the annotations.

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 main action is front-loaded and the conditions are ordered logically. It is a bit dense and stylized ('CREATING one does', 'nothing about holding a credential for one domain says anything about another'), but each sentence adds a distinct piece of information, so it 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 covers the tricky edge cases: already-owned versus newly created sites, restricted credentials, permission requirements, and the plan limitation. Since an output schema exists, return-value details are not needed. This is complete for a mutating tool with meaningful behavioral caveats.

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 the schema already explains both parameters well, including when siteId is needed and what siteUrl expects. The description adds no parameter-specific meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 specific verb and resource: 'Add another of your human's sites to their account,' and narrows the scope with 'on a plan that allows more than one.' It clearly distinguishes the tool from siblings like add_goal or ask_human by describing what it adds and when proof is needed.

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?

It explicitly tells the agent when no proof is needed (already-owned sites), when proof is required (creating a new site), and when the call is refused (restricted credential), naming cromanion_ask_human as the alternative. It also states the required site-config permission, giving clear invocation conditions.

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