Set up your client

1. Add

claude mcp add --transport http heizen https://api.studio.heizen.work/mcp \
  -H "x-heizen-toolsets: all"

That registers the server for the current project only. To have it available in every project on your machine, add --scope user:

claude mcp add --transport http --scope user heizen https://api.studio.heizen.work/mcp \
  -H "x-heizen-toolsets: all"

Use --scope project instead to write it to a checked-in .mcp.json so everyone on the repo gets the server.

2. Log in

claude mcp login heizen

Your browser opens for approval. /mcp inside a session does the same thing if you’d rather stay in the TUI.

3. Verify

claude mcp get heizen

Signing out later: claude mcp logout heizen.

1. Add

codex mcp add heizen --http-header "x-heizen-toolsets=all" \
  -- https://api.studio.heizen.work/mcp

Or write it to ~/.codex/config.toml by hand (a project-level .codex/config.toml takes precedence):

[mcp_servers.heizen]
url = "https://api.studio.heizen.work/mcp"
auth = "oauth"
http_headers = { "x-heizen-toolsets" = "all" }

2. Log in

codex mcp login heizen

3. Verify

codex mcp list

Signing out later: codex mcp logout heizen.

1. Add

{
  "mcpServers": {
    "heizen": {
      "url": "https://api.studio.heizen.work/mcp",
      "headers": { "x-heizen-toolsets": "all" }
    }
  }
}

Use .cursor/mcp.json inside a repo to scope the server to one project.

2. Log in

Open Settings → MCP. The heizen row shows Needs login — click it to start the browser approval.

3. Verify

The row turns green with the tool count next to it. Ask the agent to run whoami to confirm the account.

1. Add

{
  "servers": {
    "heizen": {
      "type": "http",
      "url": "https://api.studio.heizen.work/mcp",
      "headers": { "x-heizen-toolsets": "all" }
    }
  }
}

Or from the command line:

code --add-mcp '{"name":"heizen","type":"http","url":"https://api.studio.heizen.work/mcp"}'

2. Log in

Run MCP: List Servers from the command palette, pick heizen, then Start Server — VS Code opens the browser for approval. It also prompts on the agent’s first tool call.

3. Verify

Same MCP: List Servers entry shows Running; Show Output has the handshake if it doesn’t.

1. Add

{
  "mcpServers": {
    "heizen": {
      "httpUrl": "https://api.studio.heizen.work/mcp",
      "headers": { "x-heizen-toolsets": "all" }
    }
  }
}

httpUrl is what selects the streamable-HTTP transport — url would try SSE.

2. Log in

/mcp auth heizen

3. Verify

/mcp list

Same connector on both — claude.ai in the browser and the Claude desktop app share one list.

1. Add

Settings → Connectors → Add custom connector, paste

https://api.studio.heizen.work/mcp?toolsets=all

2. Log in

Click Connect on the connector and approve in the browser.

3. Verify

The connector lists its tools once connected. Settings → Connectors → Heizen is also where you set per-tool permissions — read-only tools can be left on Always allow, writes on Needs approval.

Custom MCP connectors live behind developer mode, on Plus, Pro, Business, Enterprise and Edu plans. On Business and above an admin has to turn connectors on for the workspace first.

1. Add

Settings → Connectors → Advanced → Developer mode, then Create a connector with

https://api.studio.heizen.work/mcp?toolsets=all

Transport is streamable HTTP and authentication is OAuth — ChatGPT registers itself with the server, so there’s no client ID to paste.

2. Log in

Approve in the browser window ChatGPT opens.

3. Verify

Start a chat, enable the Heizen connector from the composer’s tools menu, and ask it to run whoami.

Clients that only speak stdio — Windsurf, Zed, older desktop apps — bridge through mcp-remote, which runs the OAuth flow for them.

1. Add

{
  "mcpServers": {
    "heizen": {
      "command": "npx",
      "args": [
        "-y", "mcp-remote",
        "https://api.studio.heizen.work/mcp",
        "--header", "x-heizen-toolsets: all"
      ]
    }
  }
}

2. Log in

The first launch opens your browser automatically; tokens are cached in ~/.mcp-auth. To force a fresh sign-in, rm -rf ~/.mcp-auth and restart the client.

3. Verify

Ask the agent to run whoami.

Anything that speaks streamable HTTP directly can skip the bridge and use the endpoint as-is — the server advertises /.well-known/oauth-protected-resource and /.well-known/oauth-authorization-server, so a compliant client discovers and registers itself with no extra configuration.