MCP Gateway

Getting Started with MCP Gateway - Agent

MCP Gateway tutorialLocal with an AI agent

Connect an MCP client to Linear through your own gateway and call a Linear tool.

Have a coding agent build a local MCP Gateway in front of Linear. You'll complete the browser authorization yourself and verify a real Linear tool call.

Prerequisites

  • Node.js 24 or later.
  • A Zuplo account.
  • An installed coding agent and a Linear account with access to a workspace.
  • An MCP client that can connect to a local HTTP server and complete OAuth.

This tutorial uses Zuplo's local dev-login shortcut. For a hosted gateway with your identity provider, use the Portal tutorial.

Build your MCP Gateway with an agent

  1. Create your project

    Run:

    TerminalCode
    npx create-zuplo-api@latest linear-mcp-gateway cd linear-mcp-gateway

    When prompted, choose Yes to create a matching Portal project, complete sign-in, and select your Zuplo account. Select the coding agent you use when asked. The CLI creates and links the hosted project. See create-zuplo-api.

    Zuplo skills

    The scaffold installs Zuplo skills in this project for Codex and Cursor and configures the Claude Code plugin. If setup fails, follow Agent Skills from this directory before starting your agent.

  2. Give the agent the gateway configuration task

    Open your agent in the project directory and use this prompt:

    Code
    Read the project instructions and bundled Zuplo MCP Gateway docs. Build a local gateway in front of Linear using the dev-login shortcut. Use http://127.0.0.1:9000 consistently for local URLs. In modules/zuplo.runtime.ts, export runtimeInit(runtime: RuntimeExtensions), import RuntimeExtensions from @zuplo/runtime and McpGatewayPlugin from @zuplo/runtime/mcp-gateway, and register new McpGatewayPlugin(). config/policies.json must be an object containing a policies array. Add: 1. name "dev-oauth", policyType "mcp-oauth-inbound", handler module "$import(@zuplo/runtime/mcp-gateway)", export "McpOAuthInboundPolicy". options.oidc has issuer "http://127.0.0.1:9000" and jwksUrl "http://127.0.0.1:9000/jwks". options.browserLogin.url is "http://127.0.0.1:9000/__zuplo/oauth/dev-login". The OIDC values are placeholders required for local dev-login; don't create a JWKS route or claim that /jwks exists. 2. name "mcp-token-exchange-linear", policyType "mcp-token-exchange-inbound", handler module "$import(@zuplo/runtime/mcp-gateway)", export "McpTokenExchangeInboundPolicy". Its options are: { "displayName": "Linear", "protectedResourceMetadataUrl": "https://mcp.linear.app/.well-known/oauth-protected-resource", "authMode": "user-oauth", "scopes": [], "clientRegistration": { "mode": "auto" } } In config/routes.oas.json, add /mcp/linear-v1 with method key "get,post", operationId "linear-mcp-server", and x-zuplo-route.corsPolicy "none". Use McpProxyHandler from $import(@zuplo/runtime/mcp-gateway), with options { "rewritePattern": "https://mcp.linear.app/mcp" }. Attach inbound policies in this order: dev-oauth, mcp-token-exchange-linear. Run npm run dev and send an unauthenticated tools/list POST to the route. Verify 401 and a WWW-Authenticate header identifying the protected-resource metadata URL. This is only the first check; do not claim Linear works until I complete browser OAuth and run a real tool. Do not deploy dev-login. Show me the diff and the client URL.

    The Editor tutorial shows these files as copyable examples. See How it works for the gateway's sign-in and upstream authorization flows.

  3. Verify authentication is attached

    Review the diff, then run npm run dev if it isn't already running. In another terminal, send:

    TerminalCode
    curl -i -X POST http://127.0.0.1:9000/mcp/linear-v1 \ -H "Content-Type: application/json" \ -d '{"jsonrpc":"2.0","method":"tools/list","id":1}'

    Expect 401 Unauthorized and a WWW-Authenticate header pointing to /.well-known/oauth-protected-resource/mcp/linear-v1. A 404 suggests a route mismatch; for a 500, inspect the gateway's terminal output.

  4. Authorize Linear in your MCP client

    Add http://127.0.0.1:9000/mcp/linear-v1 as an HTTP MCP server in your client. See Connect MCP clients for client-specific setup.

    Keep 127.0.0.1 in the client URL to match the policy. During the browser OAuth flow, dev-login signs you in locally. On the gateway's consent page, click Connect for Linear, authorize your Linear account, then click Authorize to complete the gateway connection.

    Complete these actions yourself; the coding agent doesn't need your Linear password or tokens.

  5. Run a real tool

    Ask your client to List my open Linear issues. Approve the tool call. Check that it returns your issues, or an empty result if you have none, without an authentication error.

    If connection fails, check that the local server is running and the client uses 127.0.0.1 throughout. See Local development.

Deploy with your identity provider

Dev-login works only on loopback origins. Before sharing the gateway, replace it with your identity provider using Configure local and deployed environments, then follow Deploy to the edge. Repeat the full browser authorization and tool call against the hosted URL.

Next steps