Check purchase status

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

Beyond the annotations (readOnly, idempotent, not destructive), the description reveals cost behavior ('Free, even after payment expiry'), no payment submission, privacy handling ('Keep status_token private'), polling semantics ('not a deadline'), and error-recovery behavior. This is rich behavioral context that annotations alone do not provide.

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 dense yet highly effective: each sentence carries distinct information, from cost and payment behavior to state-specific handling and privacy. It is front-loaded with the most critical distinction ('Free... submits no payment') and uses compact labels (Pending:, Ready:) for scannability.

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 read-only status-check tool with an output schema, the description covers all essential operational aspects: when to poll, what to do when Ready, how to handle the specific error, privacy requirements, and cost/security boundaries. The existence of an output schema means return-value details are already handled elsewhere.

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 100%, with both parameters already described as recovery fields from the purchase response. The description adds that status_token should be kept private, but this is a restatement of the schema's 'private' qualifier. It references recovery.original_door and recovery.original_path for retry, but these are not tool parameters, so the added parameter semantics are minimal.

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 checks purchase status ('Pending', 'Ready') and is explicitly contrasted with payment actions ('submits no payment'). It names the exact resource (purchase) and the operation (check), and distinguishes itself from the buy_* siblings by emphasizing it is free and non-payment.

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 gives clear situational guidance: poll after retry_after_seconds, use fulfillment when Ready, and handle purchase_input_mismatch by reading status or retrying with recovery fields. It also gives a when-not ('do not pay again') but does not explicitly name alternative sibling tools like check_order or check_before_you_pay.

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