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https://github.com/hypeprinter007-stack/anchor-x402-mcp

MCP server exposing 9 anchor-x402 services as agent tools. Pay-per-call USDC via x402 on Base mainnet. Works with Claude Desktop / Claude Code / Cursor / any MCP client.
https://github.com/hypeprinter007-stack/anchor-x402-mcp

agent-payments ai-agents anthropic base-mainnet claude cursor mcp mcp-server micropayments model-context-protocol solana typescript usdc x402 x402-protocol

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MCP server exposing 9 anchor-x402 services as agent tools. Pay-per-call USDC via x402 on Base mainnet. Works with Claude Desktop / Claude Code / Cursor / any MCP client.

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README 

          
# anchor-x402-mcp



> MCP server exposing 14 [anchor-x402](https://anchor-x402.com) services as tools any Claude Desktop / Cursor / Codex / Continue agent can call. Pay-per-use USDC via x402 on Base mainnet — no API keys, no subscriptions.



## What an agent gets



Fourteen tools, $0.001–$0.05 per call.



**Commodity primitives** (9, $0.001–$0.010):



| Tool | Price | What it does |

|---|---|---|

| `anchor_hash` | $0.005 | Anchor any 32-byte hash to Base + Solana mainnet in parallel; returns both tx URLs |

| `screen_wallet` | $0.001 | OFAC SDN sanctions screening for any EVM or Solana wallet |

| `attest_decision` | $0.010 | Verify a wallet signature over (input_hash, output_hash, decision); dual-chain anchor the result |

| `decode_tx` | $0.001 | Structured decode of any mainnet tx (Base / Ethereum / Solana) |

| `resolve_name` | $0.001 | Cross-chain name resolution (ENS, Bonfida SNS) |

| `token_price` | $0.001 | USD spot price for any token by symbol or chain+contract |

| `decode_calldata` | $0.001 | 4byte selector + ABI param decode for raw EVM calldata |

| `parse_datetime` | $0.001 | Freeform datetime string → structured ISO 8601 |

| `intel_wallet` | $0.005 | Bundled wallet intelligence: balances + activity + identity + sanctions in one call |



**Universal LLM endpoints** (5, $0.01–$0.05) — added in v0.2:



| Tool | Price | What it does |

|---|---|---|

| `roast` | $0.05 | Witty 3-5 paragraph roast of any target — wallet, tweet, code, idea, anything |

| `oracle` | $0.05 | Yes/no oracle. Returns YES/NO/MAYBE + reason + dual-chain anchored `(question \| answer \| timestamp)` hash. Cryptographic receipt of when you asked. |

| `tldr` | $0.01 | Summarize a URL (fetches up to 500KB) or pasted text into 3-5 concise bullets |

| `aura` | $0.01 | Returns color, tier (S/A/B/C/D/F), score 0-9999, and a punchy 2-3 sentence aura read |

| `grade` | $0.01 | Academic letter grade (A+ to F) with red-pen marginalia and one-paragraph summary |



The investigator (`/v1/investigate`, $1.77 async) and the hosted chatbot at [chat.anchor-x402.com](https://chat.anchor-x402.com) are not included in the MCP — they're accessed directly via the HTTP API and the browser respectively.



The MCP server pays for itself — your wallet gets debited automatically for each call. No prepay, no API key, no account.



## Install



### Claude Desktop



Add to `~/Library/Application Support/Claude/claude_desktop_config.json` (macOS) or `%APPDATA%\Claude\claude_desktop_config.json` (Windows):



```json

{

  "mcpServers": {

    "anchor-x402": {

      "command": "npx",

      "args": ["-y", "anchor-x402-mcp"],

      "env": {

        "ANCHOR_WALLET_PRIVATE_KEY": "0xYOUR_BASE_WALLET_PRIVATE_KEY"

      }

    }

  }

}

```



Restart Claude Desktop. Ask: *"Anchor the hash `7646dda1564bde0ef3f3971f4c002962df64246da4aa1d8c47247e7632494710` on mainnet"* — it'll call `anchor_hash` and pay $0.005 USDC from your wallet.



### Claude Code



Add to your project's `.mcp.json`:



```json

{

  "anchor-x402": {

    "command": "npx",

    "args": ["-y", "anchor-x402-mcp"],

    "env": {

      "ANCHOR_WALLET_PRIVATE_KEY": "0xYOUR_BASE_WALLET_PRIVATE_KEY"

    }

  }

}

```



### Codex CLI (OpenAI)



Edit `~/.codex/config.toml`:



```toml

[mcp_servers.anchor-x402]

command = "npx"

args = ["-y", "anchor-x402-mcp"]



[mcp_servers.anchor-x402.env]

ANCHOR_WALLET_PRIVATE_KEY = "0xYOUR_BASE_WALLET_PRIVATE_KEY"

```



Restart `codex`. Type `/mcp` to confirm anchor-x402 shows in the loaded servers list.



### ChatGPT Desktop



Settings → **Integrations** → **MCP servers** → **Add server**. Paste:



```json

{

  "command": "npx",

  "args": ["-y", "anchor-x402-mcp"],

  "env": {

    "ANCHOR_WALLET_PRIVATE_KEY": "0xYOUR_BASE_WALLET_PRIVATE_KEY"

  }

}

```



Save, restart, the 9 tools appear in any chat with tool-use enabled.



### Cursor



Edit `~/.cursor/mcp.json` (global) or `/.cursor/mcp.json` (project-scoped):



```json

{

  "mcpServers": {

    "anchor-x402": {

      "command": "npx",

      "args": ["-y", "anchor-x402-mcp"],

      "env": {

        "ANCHOR_WALLET_PRIVATE_KEY": "0xYOUR_BASE_WALLET_PRIVATE_KEY"

      }

    }

  }

}

```



### OpenAI Agents SDK (programmatic)



```python

from openai_agents import Agent, MCPServerStdio



mcp = MCPServerStdio(

    command="npx",

    args=["-y", "anchor-x402-mcp"],

    env={"ANCHOR_WALLET_PRIVATE_KEY": "0xYOUR_BASE_WALLET_PRIVATE_KEY"},

)

agent = Agent(name="researcher", model="gpt-4o", mcp_servers=[mcp])

```



Same package, same env, programmatic instead of config-driven.



### Continue / Smithery / generic MCP client



Same shape — `command: npx`, `args: [-y, anchor-x402-mcp]`, env carries your wallet key. The MCP SDK handles transport.



Or install via [Smithery](https://smithery.ai) one-liner:

```

npx -y @smithery/cli install anchor-x402-mcp --client claude

```

(replace `--client claude` with `cursor`, `codex`, `windsurf`, etc.)



### Run standalone



```bash

ANCHOR_WALLET_PRIVATE_KEY=0xYOUR_KEY npx anchor-x402-mcp

```



Speaks MCP over stdio. Pipe into any MCP-compatible client.



## Funding your wallet



The wallet you set as `ANCHOR_WALLET_PRIVATE_KEY` needs **USDC on Base mainnet**. Any amount works — even $1 buys 100 anchor calls or 1000 commodity-tier calls. Send USDC to your wallet's Base address:



- USDC contract on Base: `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`

- Bridge from Ethereum mainnet via [bridge.base.org](https://bridge.base.org)

- Buy directly on Coinbase and withdraw to Base



The MCP server signs payments via [x402](https://github.com/coinbase/x402) — Coinbase's open HTTP-native micropayments protocol. Each request:



1. Hits an `anchor-x402` endpoint

2. Gets a 402 with payment requirements

3. Server signs a USDC transfer authorization with your private key

4. Retries the request with the signed payment — the API settles via Coinbase's facilitator



You see the response, your wallet's USDC balance ticks down by the call price. Sub-second, no ledger, no account.



## Environment variables



| Variable | Required? | Purpose |

|---|---|---|

| `ANCHOR_WALLET_PRIVATE_KEY` | Yes for paid calls | EVM private key. The wallet pays for x402 calls. |

| `ANCHOR_API_URL` | No | Override the API base URL. Default: `https://api.anchor-x402.com`. Useful for development against a self-hosted fork. |



If `ANCHOR_WALLET_PRIVATE_KEY` is unset, paid tool calls return a friendly 402 message explaining how to set it. `/health` and `/openapi.json` (not exposed as tools, but reachable via direct `curl`) work without payment.



## Security notes



- The private key lives in your MCP client's config file. **Treat it like a hot wallet** — only fund what you're willing to spend autonomously.

- Recommended: generate a fresh wallet specifically for agent use. Top up periodically; don't reuse a wallet that holds significant funds.

- The MCP server only signs USDC payment authorizations to anchor-x402's known treasury addresses (visible in the 402 response). It cannot drain your wallet to arbitrary addresses.

- Source code is fully open at [github.com/hypeprinter007-stack/anchor-x402-mcp](https://github.com/hypeprinter007-stack/anchor-x402-mcp). Audit before installing.



## Verifying anchor receipts



Every `anchor_hash` and `attest_decision` call returns Base + Solana tx URLs. These are independently verifiable on the public block explorers — agents can confirm an anchor exists without re-paying:



- Base: `https://basescan.org/tx/` — Input Data field contains the merkle root

- Solana: `https://solscan.io/tx/` — Memo program data contains the same hex



The on-chain bytes are the receipt; the API response is just a convenience wrapper around them. See [the on-chain verifiability primer](https://anchor-x402.com/trust/on-chain-verifiability) for the full verification recipe.



## Troubleshooting



**"Payment required (402). Set ANCHOR_WALLET_PRIVATE_KEY..."**

You haven't configured a wallet. Add the env var to your MCP config and restart Claude Desktop.



**"Payment failed (402). The wallet may be out of USDC..."**

Your wallet ran out. Send USDC on Base to the wallet address shown in the server's startup log (it logs `payer=0x…` to stderr).



**"anchor-x402 request failed: ..."**

Network or DNS issue. Check `https://api.anchor-x402.com/health` returns 200; if not, see the [status page](https://anchor-x402.betteruptime.com).



## Links



- **Live API:** https://api.anchor-x402.com

- **Site / trust portal:** https://anchor-x402.com

- **Status:** https://anchor-x402.betteruptime.com

- **Server source:** https://github.com/hypeprinter007-stack/anchor-x402

- **MCP server source (this repo):** https://github.com/hypeprinter007-stack/anchor-x402-mcp

- **x402 protocol:** https://github.com/coinbase/x402

- **MCP spec:** https://modelcontextprotocol.io



## License



MIT