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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, yet the description still adds real value: it never charges again, it resumes a charge whose delivery was in flight, and it collects the appraisal when ready. The word 'collect' sits in mild tension with readOnlyHint, but the surrounding text frames it as idempotent finalization rather than a new charge, so it reads as clarification rather than contradiction.

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?

Front-loads the rail identity, then scope, then behavior, then exclusions. Every sentence carries distinct information; the 'RAIL: AGENT CARD' prefix makes the routing decision immediate.

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 an output schema present, return values need no explanation, and the single required parameter is fully covered. The description supplies the routing, idempotency and in-flight-resume semantics an agent needs to call this correctly.

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, but the description adds meaning by tying operationId to the specific purchase call that produced it and contrasting it with the orderId/orderToken key used by the human-card rail. That disambiguation is genuinely useful beyond the schema text.

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 ('read one card-agent-1 charge and collect the appraisal') and scopes it to buy_appraisal_agent_card charges only. It explicitly names the two sibling tools that handle the other rails, so an agent can route without opening any schema.

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 when-to-use (charges paid under buy_appraisal_agent_card, keyed by operationId) and when-not-to-use, naming appraisal_order_status with orderId + orderToken and appraisal_purchase_status with operationId as the alternatives. Nothing is left to inference.

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