create_invoice

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

No annotations are provided, so the description carries the full burden. It only states the action and unit clarification, but does not disclose side effects (e.g., invoice expiry behavior), prerequisites (e.g., wallet must be active), or failure modes. There is no mention of how optional parameters like expires_in or memo affect the created invoice.

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 short sentences, front-loaded with the action and including only essential detail. Every word earns its place with no filler or redundancy.

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 5-parameter tool with no output schema and no annotations, the description is minimal. It does not explain how optional parameters work, nor does it explicitly differentiate from sibling invoice creation tools. The agent lacks guidance on behavior, permissions, or what the created invoice looks like, making it incomplete for reliable invocation.

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 40% (only amount and wallet_id have descriptions). The description's note that amount is in satoshis duplicates the schema's amount description, and wallet_id is already described as BTC wallet. The other three parameters (memo, expires_in, external_id) are entirely undocumented, and the description does not compensate for this gap.

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 ('Create') and resource ('Lightning invoice') with a clear scope: receive a specific amount of Bitcoin. The mention of 'specific amount' and 'satoshis for BTC wallet' distinguishes it from siblings like create_invoice_usd and create_invoice_no_amount, making the tool's role unambiguous.

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 implies when to use this tool: when a fixed-amount BTC invoice is needed, with units in satoshis. It does not explicitly list alternatives or exclusions, but the 'specific amount' wording hints at differentiation from no-amount or USD-based invoice tools. Clear context, but no explicit when-not guidance.

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