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

With no annotations, the description carries the burden and discloses non-obvious traits: the call is free, requires proof of npub ownership, and protects against balance enumeration. It doesn't detail failure behavior, but the key operational and security-relevant behaviors are stated.

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?

Three short paragraphs with no filler: the core verb+object in the first sentence, differentiation in the second, and cost/security context in the third. Every sentence earns its place and the most decision-relevant information is front-loaded.

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 two-parameter tool with an output schema, the description covers what the balance is, when to use a different tool, that it is free, and why authentication is required. Nothing an agent needs to decide whether to call it or to interpret its purpose is missing.

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% and the dpop_token description is thorough, so the schema carries parameter meaning. The description adds only the contextual statement that npub ownership proof is required, which reinforces but does not extend the schema's parameter documentation.

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?

Opens with a specific verb+resource+scope: 'Check a patron's credit balance at this operator.' It then contrasts patron spending balance with the operator's Authority balance, and the sibling list includes roastify_check_authority_balance, so the tool is clearly distinguishable.

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?

Explicitly routes the operator-balance use case to 'authority_check_balance instead' and notes this tool is free. Minor deduction because the named alternative does not exactly match the sibling roastify_check_authority_balance, but the intent is unambiguous.

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