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

With no annotations, the description carries the burden of disclosing side effects. It explains that stopping is not a cancellation and that the lease continues to the end of the paid period. It also notes the action is reversible ('the same call turns it back on'). This adds meaningful context about behavior, though it doesn't detail error cases or idempotency nuances.

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, each adding essential value: the core action, the card-only condition, and the non-cancellation clarification. It is front-loaded with the primary behavior and contains no filler or repetition.

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 simple boolean toggle with two well-documented parameters, the description covers the essential context: what it does, when it applies, and what it does not do. It omits potential error scenarios or response details, but given the tool's low complexity and lack of output schema, this is a minor gap.

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?

The schema already describes both parameters at 100% coverage: 'enabled' (false stops the next charge, true resumes it) and 'access_token' (returned by order_lease). The description reinforces the meaning of 'enabled' by paraphrasing stop/start, but it does not add significant new information beyond what the schema provides. Baseline 3 is appropriate given high schema coverage.

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: 'Stop this lease charging the customer's card again, or start it again.' It uses specific verbs (stop/start) and identifies the resource (lease card charges). It also distinguishes from siblings by clarifying it's not a cancellation and that it applies only to card subscriptions, which is a unique scope.

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 clear context for when to use the tool: only for card subscriptions, not bank transfers ('Only a card subscription can be stopped — a bank transfer is a payment the customer sends us, so there is nothing of ours to cancel'). It also explains behavioral boundaries ('Stopping is not a cancellation'). However, it does not explicitly name alternative sibling tools for other lease actions, so it lacks full explicit alternative guidance.

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