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

Annotations declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds crucial context: it creates a live payment session, returns a URL, but charges nobody by itself, and warns against completing the payment. This goes beyond the annotations by clarifying the tool's side effects (session creation without charging) and the expected agent behavior (hand off the URL).

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 three sentences, front-loaded with the core action and purpose, then adding necessary details (price, timeline, refund, and the 'never complete payment' instruction). Every sentence earns its place; there is no fluff or repetition of schema content.

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?

Given the output schema exists (so return format is documented elsewhere), the description fully covers what the tool does, when to use it, what to do with the result, and a critical precondition. An agent can safely invoke it without additional clarification.

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 baseline is 3. The description adds the age constraint ('less than 30 days old') on submission_id, which is not in the schema, and clarifies that submission_id comes from submit_pwa. Email is adequately covered by the schema, and the description adds no redundant detail. The added constraint raises the score.

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+resource ('Create a Stripe Checkout link') and a precise purpose ('upgrade an existing submission to Pro Launch'), which immediately distinguishes it from all siblings (none of which create payment links). It also specifies price, timeline, and refund policy, leaving no ambiguity about what the tool accomplishes.

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 usage direction: it requires a submission_id from submit_pwa that is less than 30 days old, and it instructs the agent to give the URL to the user and never attempt to complete the payment. This is clear, actionable guidance that also implies when not to use it (e.g., for new submissions or when the ID is stale).

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