create_invoice_no_amount

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

No annotations are provided, so the description must disclose behavioral traits. It only explains the concept of an open invoice but does not mention return value, expiry behavior, or any side effects of creating an invoice. This is insufficient for a creation tool.

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 sentences and every word contributes. It front-loads the primary action and provides a one-sentence elaboration.

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 lack of annotations and output schema, plus low parameter coverage, the description is too sparse. It explains what an open invoice is but leaves users guessing about the response format, parameter interactions, and differences from other invoice tools.

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 only 25% (only wallet_id is described). The tool description does not add any meaning for memo, expires_in, or external_id. The only implicit parameter information is the absence of an amount, which is already evident from 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 clearly identifies a specific action: creating a Lightning invoice without a fixed amount. The phrase 'open invoice' and 'payer can choose how much to send' differentiate it from sibling tools like create_invoice and create_invoice_usd.

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 conveys the use case: when an open invoice is needed. It does not explicitly name alternatives or exclusions, but the 'without a specified amount' qualifier gives clear context for when to choose this tool over fixed-amount invoice tools.

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