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

Goes well beyond the annotations by disclosing the credit cost, the 30-day durability, the idempotent re-unlock behavior ('already unlocked costs nothing again'), the account-linking prerequisite, and the no-credit no-op. None of this is derivable from readOnlyHint=false / idempotentHint=true alone, and nothing contradicts them.

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?

Four tight sentences, front-loaded with the cost and the returned artifact, followed by the consent ritual and the edge cases. No filler and nothing repeated from the schema or annotations.

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 spend-a-credit mutation with an output schema, the description covers cost, prerequisite auth, consent gating, idempotency, and failure mode. Return values are delegated to the output schema, which is correct.

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?

Both parameters are fully described in the schema, so the baseline is 3. The description nevertheless adds workflow meaning to 'confirmed' by tying it to the ask-first ritual, making it clear the flag encodes a just-given user consent rather than a static setting.

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?

Names a specific verb+resource with its full economics: spends one RegTail credit, unlocks the detailed report for a plate for 30 days, and returns the report. It also positions itself against the sibling full_report ('as full_report does'), so an agent can tell the paid-unlock path from the plain report path.

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 and when-not: ask the user first, every time, call only after they agree, and never unlock on your own initiative or to answer a general question. The re-unlock case and the no-credit case are both resolved, leaving no inference to the agent.

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