Okta Calculator MCP Server

Okta Calculator MCP Server

Simple MCP server (Streamable HTTP) that exposes basic calculator tools and validates an Okta access token on tool calls.

Features

• Calculator tools: add, subtract, multiply, divide
• Okta auth via Bearer token: tool calls require an Authorization: Bearer <okta-jwt> header
• Validation: the server verifies the token as a JWT signed by Okta using the Okta JWKS endpoint (signature, issuer, audience, expiry)
• Discovery calls (initialize, tools/list) work without a token, so gateways can list tools

Prerequisites

• Node.js 20+

Configuration

Okta config is hardcoded in src/server.ts:

• Issuer: https://truefoundry.okta.com (Okta org authorization server)
• Audience: https://truefoundry.okta.com
• JWKS: https://truefoundry.okta.com/oauth2/v1/keys

The HTTP port defaults to 8080 and can be overridden with the PORT env var.

Install, build and run

npm install
npm run build
npm start

For local development:

npm run dev

Endpoints

• POST /mcp (and POST /): MCP Streamable HTTP endpoint
• GET /health: health probe, returns {"status":"ok"}

MCP tools

Each tool takes a and b (numbers):

• add: returns a + b
• subtract: returns a - b
• multiply: returns a * b
• divide: returns a / b (errors on divide-by-zero)

Tool calls without a valid Okta Bearer token get HTTP 401:

Unauthorized: invalid or missing Okta token.

Docker

docker build -t okta-calculator-mcp .
docker run -p 8080:8080 okta-calculator-mcp

TrueFoundry MCP Gateway

Register the deployed URL as a remote MCP server with Token Passthrough auth, so the gateway forwards the caller's Okta Bearer token to this server on tool calls.