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

Annotations declare a non-read-only, non-destructive, idempotent mutation, and the description goes well beyond them: it names the cost (one credit), the unlock duration (30 days), the idempotency detail (already unlocked costs nothing), the account prerequisite, and the zero-credit no-op. This is exactly the added behavioral context the annotations cannot carry.

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 action, cost, and result are front-loaded, followed by the consent guardrail and edge cases. Five short sentences, each carrying a distinct operational fact with no padding.

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, the description needn't explain the return payload, and it covers cost, duration, idempotency, prerequisites, and failure behavior. An agent has everything needed to call this correctly and safely.

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%, so both 'plate' and 'confirmed' are already fully documented. The description reinforces the intent behind 'confirmed' (user consent), but adds no syntax or format beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 pairs a specific verb (unlock) with a specific resource (the full report for this plate) and clarifies the relationship to the sibling full_report. An agent can immediately distinguish this paid unlock from the free/read siblings 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?

It gives explicit when-to-use ('call this only after they agree'), when-not ('never unlock on your own initiative or to answer a general question'), a required precondition (user's RegTail account linked), and the repeat-call rule. Nothing about invocation timing 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.