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

With no annotations, the description fully discloses behavior: returns API key and payment_url, requires user action, explains billing model (pay-per-request, no monthly fees), and states no authentication needed. This is comprehensive for a registration tool.

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 five sentences, each adding value: purpose, return values, required user action, billing model, and authentication. It is front-loaded with the core purpose and is succinct without waste.

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 all essential aspects: purpose, output, user steps, billing, and prerequisites. For a registration tool with no output schema or annotations, it provides complete context for an AI agent to use correctly.

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 description does not need to add parameter details. The description adds no extra meaning beyond the schema, which adequately describes name, email, and password.

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 tool registers a new Zyla API Hub account, using a specific verb and resource. It distinguishes from sibling tools like account_status or get_payment_url, providing a unique purpose.

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 explicit instructions: user must open payment_url to add a credit card before making calls. It explains billing and that no authentication is needed, giving clear context for use. It lacks explicit when-not-to-use, but implies it for existing accounts.

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