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 discloses the SKU options and default, the required token persistence, the human-operation step, and the post-payment retry behavior. It also adds a caution ('Do not invent a URL') that helps constrain agent behavior.

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 compact and front-loaded, stating the core purpose first, then layering essential operational details. Every sentence contributes useful information: the SKU options, the auth-header behavior, the human-in-the-loop step, and the post-payment retry. There is no filler.

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 tool has no output schema, so the description needs to convey what the agent should do with the response. It does mention opening checkout_url, which implies the response provides a URL, but it does not explicitly describe the response shape or mention potential failure/error handling. Overall it is nearly complete for a simple two-parameter purchase tool.

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 schema already documents both parameters. The description adds value beyond the schema by specifying the concrete SKU values, their prices, and the default (verify_500). This gives the agent actionable selection information that the schema alone does not provide.

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 opens with a specific verb and object: 'Create a checkout session for verify credits.' This clearly identifies the resource being acted on and the action taken, and it is unambiguously distinct from the sibling tools (balance, receipts, verify_email). The tool's purpose is fully self-contained.

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 clear usage context by walking through the full workflow: create the session, pass the workspace token, open checkout_url for the human, and retry verify_email after payment. It does not explicitly state when not to use this tool versus alternatives, but the workflow context makes the intended use obvious.

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