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

With no annotations, the description carries the burden. It discloses key behaviors: it is free (no credits consumed), requires proof of npub ownership to prevent scraping, and returns specific data. It does not explicitly state read-only behavior, but the content and the return-value description strongly imply it.

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?

Five sentences, each with a clear role: what it does, what it returns, what it is not, cost, and auth requirement. Front-loaded with the primary verb and object; no fluff 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?

Given the tool's moderate complexity and the rich input schema plus output schema, the description covers the essential context: purpose, return contents, exclusion of tax balance, cost, and authentication. It is complete enough for an agent to invoke 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 description coverage is 100%, so the schema thoroughly documents all parameters (days, npub, dpop_token) including detailed dpop_token format and requirements. The description adds contextual flavor (e.g., 'proof of npub ownership') but does not add parameter-level semantics beyond the schema.

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 uses a specific verb ('Generate') and resource ('patron's account statement'), and clearly lists what's included (purchase history, credit tranches, per-tool usage, daily logs). It also distinguishes itself from related tools by explicitly stating it is the patron's spending account, not the operator's Authority tax balance.

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 clear context by contrasting with the Authority tax balance, implying when this statement tool is appropriate versus a balance-checking tool. However, it does not name alternative tools explicitly, so it stops short of full when/when-not guidance.

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