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

Annotations already declare destructive and idempotent behavior. The description adds valuable context: 'Requires authentication', ACP/SPT prerequisite, and the fallback path. It does not contradict annotations and goes beyond what annotations say about when this tool is appropriate.

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?

Three sentences with no filler: purpose, condition, alternative/auth. Front-loaded and efficiently structured.

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?

With output schema, annotations, and a clear usage policy, the description covers when to use, when not to use, authentication, and a fallback. It is complete for an agent to decide and invoke without additional ambiguity.

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 covers all 3 parameters with descriptions (100% coverage), so baseline is 3. The description reinforces the SPT requirement and authentication need but does not add significant detail beyond the schema.

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 starts with 'Complete payment using Stripe ACP (Shared Payment Token)', which clearly states the action, method, and resource. It distinguishes from sibling tools like checkout_create, checkout_status, and checkout_cancel by specifying the completion step.

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?

Explicitly provides conditions for use: 'Only use this if your platform supports Stripe Agentic Commerce Protocol' and names an alternative path ('use the payment_url from checkout_create instead, then poll checkout_status') when the condition is not met. This is strong guidance.

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