create_invoice

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the return type (BOLT11 string) but omits critical details: whether this is a read-only or mutating operation, authentication requirements, rate limits, error conditions, or what happens after creation (e.g., invoice lifecycle).

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 description is two concise sentences with zero waste. The first sentence states the purpose, and the second explains the return value. It's front-loaded and efficiently structured.

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 financial tool with no annotations and no output schema, the description is incomplete. It lacks details on authentication, error handling, invoice lifecycle, and how the returned string should be used. Given the complexity of Lightning payments, more context is needed for safe and effective use.

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 fully documents all parameters. The description adds no additional parameter semantics beyond what's in the schema (e.g., it doesn't explain BOLT11 format constraints or memo usage). 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 clearly states the specific action ('Create a Lightning invoice'), the resource ('to receive a payment'), and the outcome ('Returns a BOLT11 invoice string'). It distinguishes itself from siblings like 'pay_invoice' (which sends payments) and 'check_invoice_status' (which queries status).

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., wallet setup), when not to use it (e.g., for on-chain payments), or how it relates to siblings like 'create_l402_challenge' or 'pay_invoice'.

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