1s MCP Server

@one-source/mcp

Unified MCP server for OneSource — 27 tools for blockchain data and live chain queries in a single server.

What is MCP? The Model Context Protocol lets AI assistants call tools and access data sources. This server exposes both the OneSource blockchain API and its documentation as tools.

Quick Start

Claude Code

claude mcp add onesource -- npx -y @one-source/mcp@latest

Claude Desktop / Cursor

Add to your MCP config:

{
  "mcpServers": {
    "onesource": {
      "command": "npx",
      "args": ["-y", "@one-source/mcp@latest"]
    }
  }
}

Any MCP Client (stdio)

npx -y @one-source/mcp@latest

HTTP Server (self-hosted)

npx -y @one-source/mcp@latest --http
npx -y @one-source/mcp@latest --http --port=8080

Then connect your MCP client to http://localhost:3000/.

Health check: GET http://localhost:3000/health

Tools (27)

Blockchain API — Live Chain (12 tools)

Blockchain API — Chain Utilities (13 tools)

RPC only.

Setup & Ops (2 tools)

No authentication required.

Networks

All blockchain API tools accept an optional network parameter:

Authentication

Blockchain API tools require authentication. Two options are available — if both are set, API key takes priority.

Option 1: API Key

1. Go to app.onesource.io and create an account.
2. Subscribe to a developer plan (Stripe checkout).
3. Navigate to API Keys and generate a key.
4. Copy the key — it starts with sk_.

Claude Code

claude mcp add onesource -e ONESOURCE_API_KEY=<key> -- npx -y @one-source/mcp@latest

Claude Desktop / Cursor

Add the env block to your MCP config:

{
  "mcpServers": {
    "onesource": {
      "command": "npx",
      "args": ["-y", "@one-source/mcp@latest"],
      "env": {
        "ONESOURCE_API_KEY": "<key>"
      }
    }
  }
}

Any MCP Client (stdio)

ONESOURCE_API_KEY=<key> npx -y @one-source/mcp@latest

After adding, reload the MCP server and call 1s_setup_check — it should show Status: Configured (API key).

Option 2: x402 Micropayments

Blockchain API endpoints are priced in USDC on Base via x402. When you set X402_PRIVATE_KEY, the server automatically handles payments — tool calls are paid and retried transparently without any extra work from the agent.

1. Get an EVM private key — export one from MetaMask, Coinbase Wallet, or any EVM wallet, or generate a fresh one. The key is a 64-character hex string. The 0x prefix is optional — both formats are accepted.
2. Pass the key to the server using one of the methods below.
3. Reload and find your wallet address — reload the MCP server, then call 1s_setup_check. It will show the wallet address derived from your key under "Wallet address".
4. Fund that address with USDC on Base — send USDC to the address shown in 1s_setup_check, on the Base network. A few dollars ($1–5 USDC) is enough for hundreds of calls. If your USDC is on Ethereum mainnet, bridge it using the Base Bridge.
5. Verify — call 1s_network_info for ethereum. If it returns chain data (block number, gas price), x402 payments are working end-to-end.

Claude Code

claude mcp add onesource -e X402_PRIVATE_KEY=<key> -- npx -y @one-source/mcp@latest

Claude Desktop / Cursor

Add the env block to your MCP config:

{
  "mcpServers": {
    "onesource": {
      "command": "npx",
      "args": ["-y", "@one-source/mcp@latest"],
      "env": {
        "X402_PRIVATE_KEY": "<key>"
      }
    }
  }
}

Any MCP Client (stdio)

X402_PRIVATE_KEY=<key> npx -y @one-source/mcp@latest

Config File Locations

If you prefer editing the config file directly instead of using CLI commands:

Add the onesource entry inside "mcpServers" using the JSON block shown above.

Alternative: Set as an Environment Variable

Instead of the env config block, you can set either variable as a shell or system environment variable: export ONESOURCE_API_KEY=<key> (bash/zsh) or $env:ONESOURCE_API_KEY = "<key>" (PowerShell). Set it at the OS level for persistence across sessions.

Security

Never commit keys to source control. Use environment variables, a .env file (excluded from git), or a secrets manager.

After any config change: Run /reload-plugins in Claude Code, or restart Claude Desktop / Cursor. The MCP server must be reloaded to pick up new environment variables.

Environment Variables

Troubleshooting

1s_setup_check shows "Not configured" Set either ONESOURCE_API_KEY or X402_PRIVATE_KEY. Reload the MCP server after setting either variable (see note above). If the key still isn't reaching the server, set it as a shell environment variable directly.

Getting 403 / wrong key active despite correct setup A key set in your shell profile (e.g. ~/.zshrc, ~/.bash_profile) is picked up by the MCP server process even if it isn't in your Claude MCP config. Run echo $ONESOURCE_API_KEY in your terminal to check. If it prints a value you didn't intend, unset it (unset ONESOURCE_API_KEY) or explicitly clear it when adding the server: claude mcp add onesource -e ONESOURCE_API_KEY= -e X402_PRIVATE_KEY=<key> -- npx -y @one-source/mcp@latest. 1s_setup_check shows the first 6 characters of whichever key is active so you can confirm which one the server is using.

Instructions show wrong auth method after reinstall /reload-plugins in Claude Code reconnects tools but may not refresh the system prompt the LLM sees. If you switch auth method (e.g. API key → x402), do a full Claude Code restart to ensure the instructions reflect the new auth.

"MCP server onesource already exists" error Run claude mcp remove onesource first, then re-add with your updated config.

Windows: npx requires cmd /c wrapper Claude Code's /doctor command may warn about this. Update your MCP config to use "command": "cmd" with "args": ["/c", "npx", "-y", "@one-source/mcp@latest"].

npx hangs with no output That's normal — stdio mode waits for JSON-RPC input on stdin. Use --http if you want an HTTP server you can curl.

Port already in use Specify a different port: npx -y @one-source/mcp@latest --http --port=8080

Registry Publishing

This package is listed on the official MCP Registry under the verified namespace io.onesource/mcp and on Glama. When releasing a new version, update both registries.

MCP Registry

First-Time Setup

1. Install Go

Download the installer for your platform from go.dev/dl and run it. Verify:

go version

2. Install mcp-publisher

go install github.com/modelcontextprotocol/registry/cmd/mcp-publisher@latest

If the Go module path has changed and the command fails, download the binary directly from the mcp-publisher GitHub releases page instead.

On Windows, add Go's bin directory to your PATH if the command isn't recognized:

$env:PATH += ";$env:USERPROFILE\go\bin"

Verify:

mcp-publisher --help

3. DNS Authentication (already done)

The onesource.io domain has a DNS TXT record that proves ownership of the io.onesource namespace. This is already configured — you don't need to redo it.

The record is on the root domain (onesource.io, not _mcp-registry.onesource.io):

v=MCPv1; k=ed25519; p=7D3U5rufgNXb/lH2MthTRZdDzEGeE7/Jvg8YkiArQc8=

You can verify it resolves:

nslookup -type=TXT onesource.io 8.8.8.8

4. Get the Private Key

Authentication requires the ed25519 private key in hex format that corresponds to the public key in the DNS record. Ask the team lead for this key — it's stored in the team's password manager / vault.

If you need to regenerate the keypair (this invalidates the current DNS record and requires updating it):

1. Generate a new ed25519 keypair (e.g., openssl genpkey -algorithm Ed25519 -out key.pem)
2. Extract the raw 32-byte private key seed and convert to hex:

   openssl pkey -in key.pem -outform DER | tail -c 32 | xxd -p -c 32
   

3. Extract the public key in base64 for the DNS TXT record:

   openssl pkey -in key.pem -pubout -outform DER | tail -c 32 | base64
   

4. Update the DNS TXT record on onesource.io with the new public key:

   v=MCPv1; k=ed25519; p=<base64-public-key>
   

5. Wait for DNS propagation before attempting to log in.

Publishing a New Version

Every time you release a new npm version, update the MCP Registry:

1. Publish to npm (the registry validates the package exists, so this must happen first):

   npm run build
   npm publish --access public
   

2. Update server.json — set both version fields to match the new npm version:

   {
     "version": "x.y.z",
     ...
     "packages": [{ "version": "x.y.z", ... }]
   }
   

   The mcpName field in package.json must be "io.onesource/mcp" and must match the name field in server.json. This is already set — don't remove it.

3. Authenticate (tokens expire, so do this each time):

   mcp-publisher login dns --domain onesource.io --private-key <ed25519-hex-private-key>
   

4. Publish to the registry:

   mcp-publisher publish
   

5. Verify:

   curl "https://registry.modelcontextprotocol.io/v0.1/servers?search=onesource"
   

Glama

Glama auto-syncs from the GitHub repo daily. No manual steps needed after a release — just make sure changes are pushed to main. The glama.json file in the repo root controls ownership. Manual re-sync is available from the Glama admin panel after claiming the server.

License

Apache 2.0 — see LICENSE for details.