decode_invoice

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

No annotations are provided, so the description carries full burden. It discloses the tool's purpose (inspection/decoding) and output fields (amount, expiry, destination), which is helpful. However, it doesn't mention behavioral aspects like error handling, rate limits, or authentication requirements, leaving gaps for a tool with no annotation coverage.

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 a single, efficient sentence that front-loads the core purpose ('Decode a Lightning invoice') and adds essential context ('to inspect amount, expiry, destination before paying'). Every word earns its place with zero waste.

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 no annotations and no output schema, the description provides basic purpose and usage context but lacks details on return values, error cases, or system behavior. For a decoding tool with 1 parameter, it's minimally adequate but leaves significant gaps in completeness.

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%, with the single parameter 'invoice' well-documented in the schema as 'BOLT11 Lightning invoice to decode'. The description adds no additional parameter details beyond what the schema provides, so it meets the baseline of 3 for high schema coverage.

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 ('decode'), resource ('Lightning invoice'), and purpose ('to inspect amount, expiry, destination before paying'). It distinguishes from siblings like 'pay_lightning_invoice' by focusing on inspection rather than payment.

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 states when to use this tool: 'before paying' a Lightning invoice. This provides clear context for usage versus alternatives like 'pay_lightning_invoice' (for actual payment) or 'create_lightning_invoice' (for invoice creation).

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