Decode BOLT11 Lightning invoices to extract payment details and verify transaction information for Bitcoin payments.
Decode a Lightning invoice
| Name | Required | Description | Default |
|---|---|---|---|
| invoice | Yes | BOLT11 Lightning invoice |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the action 'decode' but doesn't explain what decoding entails (e.g., extracting payment details, checking validity, or returning structured data). For a tool with zero annotation coverage, this leaves significant gaps in understanding its behavior and output.
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 with zero waste. It's front-loaded with the core action and resource, making it easy to parse quickly. No unnecessary words or redundant information are included.
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, the description is incomplete. It doesn't explain what the tool returns (e.g., decoded fields like amount, timestamp, or destination) or potential errors (e.g., invalid invoice format). For a decoding tool with no structured output documentation, this leaves the agent guessing about results.
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 parameter 'invoice' documented as a 'BOLT11 Lightning invoice'. The description doesn't add any meaning beyond this, such as format examples or validation rules. Since the schema already provides adequate coverage, the baseline score of 3 is appropriate.
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 verb 'decode' and the resource 'Lightning invoice', making the purpose immediately understandable. It doesn't differentiate from siblings like 'decode_tx' or 'pay_invoice', but the core action is specific enough to understand what the tool does.
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 like 'decode_tx' or 'validate_address'. It doesn't mention prerequisites, such as needing a valid BOLT11 invoice, or clarify that this is for decoding rather than processing payments (which 'pay_invoice' handles).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.