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

With no annotations provided, the description carries full responsibility for disclosing behavior. It reveals that the checkout is locked after calling, that payment confirmation is asynchronous via webhook, and that a payment_url is returned. This exceeds what basic annotations would provide and gives crucial operational context.

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 information-dense, with every sentence providing essential details: phase, purpose, return value, async confirmation, and locking side-effect. The front-loaded structure ensures the agent quickly grasps the core function and key caveats.

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 two-parameter tool with no output schema and no annotations, the description is unusually complete. It covers purpose, side-effects, next steps, and alternatives, making it sufficient for an agent to use correctly without needing external documentation.

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?

Although the schema description coverage is only 50% (checkout_id lacks a description), the tool description enriches the meaning of both parameters. It clarifies that payment_method choices correspond to specific payment types, and the 'Phase 2' context implies checkout_id comes from create_checkout. This compensates reasonably for the schema gap, though explicit mention of checkout_id would be clearer.

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's function: it finalises a checkout and generates a payment link, with the specific options Yoco and Ozow. It distinguishes itself from sibling tools by positioning as 'Phase 2 of 2' and explicitly contrasting with cancel_checkout.

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 concrete guidance on when to use this tool vs alternatives. It mentions to use cancel_checkout if the customer changes their mind, and to poll get_order to confirm payment status, giving a clear workflow and exclusion criteria.

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