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

With no annotations, the description carries the full burden and does meaningful work: it explicitly states 'Nothing is charged by calling this' and that the operator decides spending scope. It also clarifies that sending the named amount settles the invoice. It does not disclose idempotency or whether repeated calls create duplicate invoices, but the provided behavioral context is strong.

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 short sentences, each carrying relevant information. The main purpose is front-loaded, and the cost-safety and settlement mechanics are stated efficiently without repetition or filler.

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?

The description covers purpose, cost safety, and settlement behavior, but with no output schema it does not specify what the tool returns beyond naming the amount, asset, chain, and address. It also leaves termDays and tier semantics unexplained, which is a notable gap for a tool with only three parameters.

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 only 33%; only asset has a description. The description mentions 'exact amount, the asset, the chain and the address,' but these do not map clearly to the actual parameters (tier, asset, termDays). It does not explain what tier or termDays mean or how they influence the invoice amount, so the agent is left guessing on most parameters.

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 states a specific action and resource: 'Request an invoice for a pass.' It clearly communicates the core function and adds useful detail about what the invoice contains. However, it does not differentiate from the sibling tool claim_invoice, so the agent must infer which operation is appropriate.

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?

The description gives no explicit guidance on when to use mint_invoice versus alternatives like claim_invoice or invoice. The sentence about the operator deciding spending scope hints at authorization conditions but does not provide a clear when-to-use or when-not-to-use rule.

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