⚓️ Truth Anchor Agent

Truth Anchor Agent is an MCP (Model Context Protocol) server that provides a verifiable grounding layer for AI agents. It verifies URL status and content accessibility, gated by on-chain USDC micro-payments on Base via the x402 protocol.

The Problem: AI agents often reference dead links or hallucinate sources. The Solution: A trustless, pay-per-verification service that requires agents to commit a micro-payment before confirming a source's validity.

---

🛠 Model Context Protocol (MCP) Integration

This server exposes a verify tool that any MCP-compliant LLM (Claude Desktop, ChatGPT, IDEs) can use autonomously.

Registration in Claude Desktop

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "truth-anchor": {
      "command": "npx",
      "args": ["-y", "truth-anchor-agent"],
      "env": {
        "MY_WALLET_ADDRESS": "0x367B9193D4F9cb4877Ca58E6F3ce944d761d8009"
      }
    }
  }
}

---

💳 The x402 Flow

The agent implements the HTTP 402 Payment Required standard, enabling seamless AI-to-AI economic transactions.

1. Request: Agent calls /verify with a URL.
2. Challenge: Server returns 402 Payment Required with payment instructions.
3. Payment: Agent executes a 0.005 USDC transfer on Base Mainnet.
4. Verification: Agent retries with the transaction hash in the X-402-Payment-Token header.
5. Truth: Server validates the hash on-chain (preventing replays) and returns the status.

---

⚡️ API Reference

POST /verify

Verifies a URL's status. Requires a valid Base transaction hash.

Headers:

Header	Description
X-402-Payment-Token	The transaction hash of the 0.005 USDC payment on Base

Request Body:

{ "url": "https://base.org" }

Success Response (200 OK):

{
  "url": "https://base.org",
  "is_live": true,
  "status_code": 200,
  "payment_verified": true
}

---

🏗 Tech Stack

• FastAPI — High-performance Python API framework.
• Web3.py — Real-time on-chain verification (Base RPC).
• SQLite — Replay attack prevention and transaction indexing.
• Fly.io — Global edge deployment.
• Base — L2 Ethereum for fast, low-cost USDC payments.

---

🛠 Local Development

# 1. Clone and Install
git clone https://github.com/cristiano-c1/truth-anchor-agent
cd truth-anchor-agent
pip install -r requirements.txt

# 2. Configure
echo "MY_WALLET_ADDRESS=0x367B9193D4F9cb4877Ca58E6F3ce944d761d8009" > .env

# 3. Run
uvicorn main:app --reload

---

📜 License

Distributed under the MIT License. See LICENSE for more information.