@three-ws/ibm-x402-mcp

A Model Context Protocol server that exposes IBM Granite foundation models as pay-per-use tools via the x402 payment protocol. End users pay USDC on Solana per call — no IBM Cloud account of their own. The server operator supplies IBM credentials (WATSONX_*) and a receiving Solana wallet (MCP_SVM_PAYMENT_ADDRESS); callers supply only USDC. One free tool (ibm_granite_getting_started) explains prices and the flow before any payment.

Built by three.ws. Community-built and not affiliated with IBM.

How it works

1. An MCP client (Claude Desktop, Claude Code, Cursor, or an agent) connects to this server.

2. The client calls a tool — e.g. ibm_granite_chat.

3. Without an x402 payment payload, the server returns a 402 PaymentRequired envelope quoting the USDC price and the Solana receiving address.

4. The client signs a Solana USDC transfer and retries with the payment in _meta["x402/payment"].

5. The server verifies and settles the payment via the facilitator, calls IBM watsonx.ai, and returns the result with a settlement receipt in _meta["x402/payment-response"].

x402-capable MCP clients handle this loop automatically.

Related MCP server: maxia-mcp

Install

npm install @three-ws/ibm-x402-mcp

Run it directly with npx (no install needed):

MCP_SVM_PAYMENT_ADDRESS=<your-solana-wallet> \
WATSONX_API_KEY=<ibm-api-key> \
WATSONX_PROJECT_ID=<watsonx-project-id> \
npx @three-ws/ibm-x402-mcp

Or install globally for the ibm-x402-mcp binary on your PATH:

npm install -g @three-ws/ibm-x402-mcp

Quick start

With Claude Code, one command (as an end user paying per call, no env vars needed):

claude mcp add ibm-granite-x402 -- npx -y @three-ws/ibm-x402-mcp

Server operators add -e MCP_SVM_PAYMENT_ADDRESS=... -e WATSONX_API_KEY=... -e WATSONX_PROJECT_ID=... before the --.

Or wire the server into your MCP client config (claude_desktop_config.json, Cursor's mcp.json):

{
	"mcpServers": {
		"ibm-x402": {
			"command": "npx",
			"args": ["-y", "@three-ws/ibm-x402-mcp"],
			"env": {
				"MCP_SVM_PAYMENT_ADDRESS": "your-solana-wallet-address",
				"WATSONX_API_KEY": "your-ibm-cloud-api-key",
				"WATSONX_PROJECT_ID": "your-watsonx-project-id"
			}
		}
	}
}

Inspect the tool surface with the MCP Inspector:

npx -y @modelcontextprotocol/inspector npx @three-ws/ibm-x402-mcp

Tools

Every tool is a read-only model-inference call — nothing on your machine or in any account is modified — and declares MCP tool annotations (readOnlyHint, openWorldHint, idempotentHint) so clients can reason about side effects before paying.

Input parameters

ibm_granite_chat — messages (required: 1–50 { role, content } pairs), model, max_new_tokens (1–4096, default 1024), temperature (0–2, default 0.7).

ibm_granite_code — task (required: generate/review/refactor/explain/test/document), prompt (required), language, context.

ibm_granite_embed — inputs (required: 1–64 texts, ≤8000 chars each), model.

ibm_granite_analyze — document (required), analysis_type (general/contract/financial/technical/medical/sentiment, default general), language.

ibm_granite_forecast — timestamps (required: 64–1024 ISO-8601, uniform cadence, oldest first), values (required: 64–1024 numbers, same length), freq (required: pandas cadence, e.g. 1h, 1D), prediction_length (1–96), label.

Example calls

// ibm_granite_chat
{
  "messages": [
    { "role": "system", "content": "You are an expert data engineer." },
    { "role": "user", "content": "Design a lakehouse schema for IoT sensor telemetry." }
  ],
  "max_new_tokens": 1024,
  "temperature": 0.7
}

// ibm_granite_code
{ "task": "review", "prompt": "def calculate_roi(revenue, cost): return revenue / cost", "language": "Python" }

// ibm_granite_embed
{ "inputs": ["enterprise data governance", "cloud-native AI pipeline", "real-time analytics"] }

// ibm_granite_analyze
{ "document": "This Software License Agreement is entered into between...", "analysis_type": "contract" }

// ibm_granite_forecast  (timestamps/values must be 64–1024 points; abbreviated here)
{ "timestamps": ["2025-01-01T00:00:00Z", "...", "2025-03-05T00:00:00Z"], "values": [12500, "...", 13200], "freq": "1D", "prediction_length": 14, "label": "daily_revenue_usd" }

Payment flow

This server uses the x402 protocol for micropayments:

1. Client calls a tool without payment → 402 PaymentRequired with the USDC amount and Solana address.

2. Client builds and signs a Solana USDC transfer transaction.

3. Client retries with the signed tx in _meta["x402/payment"].

4. Server verifies and settles via the configured facilitator (default PayAI).

5. Server calls IBM watsonx.ai and returns the result with _meta["x402/payment-response"] (settlement receipt).

MCP Client (Claude Desktop / Cursor / agent)
       │  tools/call (with x402 payment in _meta)
       ▼
ibm-x402-mcp (stdio MCP server)
       │  verify + settle USDC on Solana
       ├──► x402 facilitator (default https://facilitator.payai.network)
       │
       │  inference call with IAM Bearer token
       └──► IBM watsonx.ai (us-south.ml.cloud.ibm.com)
                 └── IBM Granite 3 8B Instruct / Embedding / TTM

Requirements

• Node.js >= 20.

• A Solana wallet address to receive USDC (MCP_SVM_PAYMENT_ADDRESS).

• IBM Cloud credentials: an API key (create one) and a watsonx.ai project id (Project → Manage → General → Project ID), or a deployment space id.

Environment variables

Regional hosts: us-south, eu-de, eu-gb, jp-tok, au-syd, ca-tor — e.g. https://eu-de.ml.cloud.ibm.com.

Related

• @three-ws/ibm-watsonx-mcp — the same IBM Granite tools driven by your own IBM Cloud credentials (no x402, no per-call payment).

Links

• Homepage: https://three.ws

• Changelog: https://three.ws/changelog

• Issues: https://github.com/nirholas/three.ws/issues

• License: Apache-2.0 — see LICENSE

License

Copyright © 2026 nirholas. All rights reserved.

This software is proprietary — see LICENSE. No rights are granted without the express written permission of the copyright owner.