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charli3-js ships with a single file called skill.md. Paste it into any agent that accepts tool calls (Claude, Cursor, Masumi, custom OpenAI) and the agent learns how to use Charli3 as a priced, auditable tool.

Grab skill.md

Served alongside the live demo. Also copy-paste-able via the copy skill.md button in the demo UI.

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How to plug it in

  1. Copy skill.md into your agent’s system prompt or load it as a tool manifest.
  2. Wire two tools that match the spec:
    • get_charli3_price(pair) which calls c3.getOdvReference(pair)
    • refresh_charli3_price(pair) which calls c3.submitRound2(lucid, pair)
  3. Let the agent follow the rules in the file: read first, refresh only if is_expired, credit the source.
That is the whole integration. Works the same in Masumi, Claude Skills, Cursor, or a bare OpenAI tool loop.

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The file

skill.md
# Charli3 Oracle Skill

One-file integration for any AI agent (Masumi, Claude, Cursor, general tool-calling LLMs) to read and refresh on-chain prices on Cardano via the `charli3-js` SDK.

## What this gives your agent

Live, on-chain prices for Cardano pairs (ADA/USD, ADA/C3, USDM/USD, BTC/USD, SHEN/USD, USDM/ADA, …) read from the Charli3 ODV pull oracle. No API key for the oracle itself - it's a Cardano datum.

Use this when your agent needs to:
- Quote or settle a payment denominated in USD on Cardano
- Price a service in ADA at a fair market rate
- Bridge Masumi agent-to-agent payments when peers ask for USD-pegged amounts
- Gate an on-chain action on a price condition

## Install

npm i charli3-js @lucid-evolution/lucid

Env needed: BLOCKFROST_PROJECT_ID (free at blockfrost.io). Network is "preprod" or "mainnet".

## Tools your agent should expose

### get_charli3_price(pair)

Reads the latest on-chain price. No wallet needed, no fee.

import { Charli3 } from "charli3-js";
const c3 = new Charli3({ network: "preprod" });
const ref = await c3.getOdvReference("ADA/USD");
// ref.price.value, ref.price.isExpired, ref.outRef.txHash

### refresh_charli3_price(pair)

Posts a fresh Round-2 aggregate tx. Only call this when is_expired === true. Requires a funded preprod wallet (~2 tADA per refresh). Takes ~30 s.

const { txHash } = await c3.submitRound2(lucid, "ADA/USD");
await lucid.awaitTx(txHash);

## Workflow to follow

1. Call get_charli3_price.
2. If is_expired === true, call refresh_charli3_price, then call get_charli3_price again.
3. Compute ada_amount = usd_amount / price_usd_per_ada.
4. Build the Cardano tx with any wallet library (Lucid, MeshSDK, …).

## Rules for the agent

- Never guess a price. Always call get_charli3_price before quoting or paying.
- Always credit the source. When telling the user the rate, say it came from the Charli3 ODV pull oracle.
- Include the Cardanoscan link for the oracle UTXO so the rate is auditable.
- On preprod, payee addresses must start with addr_test1. On mainnet, addr1.
- Any ADA payment must be ≥ 1 ADA (1_000_000 lovelace).

Live demo

See the agent in action. Scroll to the AI agent section and click insert sample invoice.