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

Annotations already declare non-destructive, idempotent, open-world behavior, but the description adds real value beyond them: 'this call stores consent and limits but does not charge the card' and 'reuse idempotency_key on retries.' It does not cover what happens to prior consent or SetupIntent expiry, which keeps it from a 5.

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 tight sentences, front-loaded with the core action, then the required call sequence, then the safety constraints. 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?

For a consent-storing mutation with no output schema, the description covers prerequisites, the handoff sequence, the no-charge guarantee, and hints at a returned client_secret. The main residual gap is the undisclosed meaning of the four required parameters.

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 description coverage is 0% across six parameters, so the description must carry the burden. It only explains idempotency_key usage and alludes vaguely to 'limits'; it says nothing about payment_authorized, consent_version, valid_days, or the per-purchase/day cent ceilings.

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?

States a specific verb and resource (create a Stripe SetupIntent) scoped to 'this authenticated machine' and gated on saved-card consent. It is clearly distinguishable from siblings like sync_card_authorization and card_payment_terms, which are named in the workflow.

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?

Gives explicit ordering and alternatives: 'Call card_payment_terms first, then complete the returned client_secret with Stripe.js and call sync_card_authorization.' It also states a hard exclusion ('never send PAN/CVC to this tool'), so the agent knows both when and how not to use it.

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