nwc-mcp

nwc_pay_lnurl

Pay a raw LNURL-pay endpoint (bech32 lnurl1... string) to send satoshis. Decodes the LNURL, resolves the pay request, and applies safety checks: allowlist, budget cap, optional confirmation.

Instructions

Pay a raw LNURL-pay endpoint (bech32 lnurl1... string). Decodes the LNURL, resolves the pay request, then runs the safety pipeline (read-only gate, allowlist check on the LNURL, budget cap, optional two-step confirmation). Use nwc_pay_lightning_address when you have a name@domain.tld instead.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "lnurl": "<lnurl>",
      "amount_sats": "<amount_sats>"
    },
    "name": "nwc_pay_lnurl"
  }
}

Input Schema

Name	Required	Description
`lnurl`	Yes	A raw LNURL string (bech32, starts with lnurl1...; an optional lightning: prefix is stripped).
`comment`	No	Optional comment, only sent if the endpoint advertises LUD-12 comment support.
`amount_sats`	Yes	Amount to send in satoshis. Must fall within the endpoint's [min, max] range.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 2, 2026

TDQS

A4.5/5.0

Behavior5/5

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

With no annotations, the description carries the full disclosure burden. It goes beyond 'pay' by detailing the internal pipeline: decodes LNURL, resolves pay request, runs safety pipeline (read-only gate, allowlist check, budget cap, optional two-step confirmation). This provides crucial behavioral context about constraints and side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and well-structured: the first sentence states the core function, the second explains the internal process, and the third provides an alternative tool. Every sentence serves a purpose, with no redundancy or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers purpose, process, and constraints thoroughly, but there is no output schema and no mention of what the tool returns. Since optional two-step confirmation is mentioned, the agent is left without guidance on how to handle that flow or what response to expect, creating a notable gap for a payment tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, as all three parameters are documented in the input schema including format, range, and LUD-12 comment support. The description adds no parameter-specific information beyond what the schema already states, so 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.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Pay') with a clear resource ('raw LNURL-pay endpoint'), and immediately distinguishes itself from the sibling tool nwc_pay_lightning_address. It also specifies the input format (bech32 lnurl1... string), leaving no ambiguity about what this tool does.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Clear guidance is provided: use this tool for raw LNURL strings, and use nwc_pay_lightning_address for name@domain.tld addresses. This explicit alternative tells the agent exactly when to choose this tool over a closely related sibling, qualifying as strong usage guidance.

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

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