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MCP Server Setup

Connect your AI agent to Vector blockchain via the MCP server.

What is the Vector MCP Server?

The Vector MCP server is a Model Context Protocol server that exposes Vector blockchain operations as tools. Any MCP-compatible AI client (Claude Desktop, OpenClaw, LangChain, CrewAI, custom agents) can connect to it and immediately interact with Vector.

The server handles:

  • Wallet management (key derivation, address generation)
  • Transaction building, signing, and submission
  • Chain queries (balances, UTxOs, history, protocol parameters)
  • Smart contract deployment and interaction
  • Agent registry operations (register, update, transfer, deregister, discover, message)
  • Safety controls (spend limits, audit logging, dry-run)

Transport: SSE (Server-Sent Events) over HTTPS.

Mnemonic handling: The wallet mnemonic is passed per-call by the MCP client — it is NOT stored in the server environment.

Connect to the Hosted Server

The Vector MCP server is hosted and publicly available — no installation required. Connect your AI client directly.

No authentication, no API keys, no environment variables needed.

Claude Code (Terminal)

One command:

claude mcp add --transport sse vector-mcp https://mcp.vector.testnet.apexfusion.org/sse

To make it available across all your projects, add --scope user:

claude mcp add --transport sse vector-mcp https://mcp.vector.testnet.apexfusion.org/sse --scope user

claude mcp add --transport sse vector-mcp https://mcp.vector.mainnet.apexfusion.org/sse

To make it available across all your projects, add --scope user:

claude mcp add --transport sse vector-mcp https://mcp.vector.mainnet.apexfusion.org/sse --scope user

That's it — all 18 Vector MCP tools are immediately available in Claude Code.

Claude Desktop

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

{
  "mcpServers": {
    "vector-mcp": {
      "type": "sse",
      "url": "https://mcp.vector.testnet.apexfusion.org/sse"
    }
  }
}

{
  "mcpServers": {
    "vector-mcp": {
      "type": "sse",
      "url": "https://mcp.vector.mainnet.apexfusion.org/sse"
    }
  }
}

Restart Claude Desktop after saving. See Claude Desktop + Vector for a full walkthrough.

Claude.ai (Web / Mobile)

Go to Settings → Connectors → Add custom connector, then enter:

https://mcp.vector.testnet.apexfusion.org/sse

https://mcp.vector.mainnet.apexfusion.org/sse

Project-Level Setup

For team collaboration, commit a .mcp.json file to your project root:

{
  "mcpServers": {
    "vector-mcp": {
      "type": "sse",
      "url": "https://mcp.vector.testnet.apexfusion.org/sse"
    }
  }
}

{
  "mcpServers": {
    "vector-mcp": {
      "type": "sse",
      "url": "https://mcp.vector.mainnet.apexfusion.org/sse"
    }
  }
}

Anyone who opens the project with Claude Code will automatically pick up the Vector MCP server.

Other MCP Clients

Connect any MCP-compatible client to the SSE endpoint:

https://mcp.vector.testnet.apexfusion.org/sse

https://mcp.vector.mainnet.apexfusion.org/sse

No additional configuration required — the hosted server handles all chain access internally.

Source repository: github.com/Apex-Fusion/mcp-server

Testnet uses mainnet network ID

Vector testnet uses mainnet network ID (networkMagic: 764824073). Wallet addresses start with addr1, not addr_test1.

Wallet Modes

Agent-Controlled Mode (Default)

The agent holds the wallet keys and can sign transactions autonomously, within spend limits.

Best for: autonomous agents with defined budgets, testnet experimentation, low-value operations.

Transaction-Crafter Mode

The agent builds transactions but returns them unsigned. A human (or separate signing service) must sign and submit.

Best for: high-value operations, institutional use, any scenario requiring human approval on every transaction.

In this mode, tools like vector_send_apex return an unsigned transaction (CBOR hex) instead of submitting.

Spend Limits

Spend limits are enforced at the server level. They cannot be bypassed by the agent.

Limit Default Description
Per-transaction 100 AP3X (100,000,000 DFM) Max value in a single transaction
Daily 500 AP3X (500,000,000 DFM) Cumulative max per calendar day (UTC)

The daily limit resets at midnight UTC. The agent can check current usage via vector_get_spend_limits.

Audit Log

When enabled (default), every MCP tool invocation is logged to the audit log path:

{
  "timestamp": "2026-03-16T10:30:00Z",
  "tool": "vector_send_apex",
  "params": {"recipientAddress": "addr1...", "amount": 5},
  "result": "success",
  "tx_hash": "abc123...",
  "fee": 180000,
  "spend_total_daily": 5180000
}

Read the JSON file directly, or query it programmatically.

Endpoint Reference

Service Testnet Mainnet
Ogmios https://ogmios.vector.testnet.apexfusion.org https://ogmios.vector.mainnet.apexfusion.org
TX Submit https://submit.vector.testnet.apexfusion.org/api/submit/tx https://submit.vector.mainnet.apexfusion.org/api/submit/tx
Koios https://v2.koios.vector.testnet.apexfusion.org/ https://koios.vector.mainnet.apexfusion.org/
Explorer https://vector.testnet.apexscan.org https://explorer.vector.mainnet.apexfusion.org

Troubleshooting

Connection errors

Check endpoint availability:

curl -s https://ogmios.vector.testnet.apexfusion.org/health

If the endpoint is down, check the Apex Fusion status page or flag it with the team.

"Spend limit exceeded"

Check your current limits and usage via the vector_get_spend_limits tool. Either increase the limit or wait for the daily reset (midnight UTC).

Transaction failures

  • "Insufficient funds" — balance too low for amount + fee + min UTxO
  • "UTxO contention" — another transaction consumed a needed UTxO; retry
  • "Validation failed" — smart contract validator returned false; check datum/redeemer

Next Steps