Connecting a Client

How to add the Subscriptions Engine MCP server to Claude Desktop, Claude web, Cursor, Codex, and MCP Inspector.

Connecting a Client

The MCP server accepts any client that supports the Streamable HTTP transport. You’ll always need two things:

1. The endpoint: https://mcp.oluwadunsin.dev/mcp
2. Your merchant API key, sent as an X-Api-Key header.

You can grab or rotate the API key from POST /auth/rotate-api-key.

Claude Desktop (GUI)

1. Open Claude Desktop → click your profile / name → Settings.
2. Go to Connectors (older builds call this Developer → MCP Servers).
3. Click Add custom connector.
4. Fill in:
   • Name: Subscriptions Engine
   • URL: https://mcp.oluwadunsin.dev/mcp
   • Transport: Streamable HTTP
   • Custom header: X-Api-Key = <your merchant api key>
5. Save. All 15 tools appear in the tool picker inside every chat.

Claude Desktop (JSON config)

For older Claude Desktop builds, edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "subengine": {
      "transport": {
        "type": "streamable-http",
        "url": "https://mcp.oluwadunsin.dev/mcp",
        "headers": { "X-Api-Key": "<your merchant api key>" }
      }
    }
  }
}

Restart Claude Desktop for the change to take effect.

Claude web (claude.ai)

The web app supports custom connectors on Pro / Team+ plans.

1. claude.ai → click profile → Settings → Connectors.
2. Add custom connector.
3. Name, URL, and X-Api-Key header exactly like the Desktop flow above.

If the Connectors tab isn’t visible, your plan doesn’t include it — fall back to Claude Desktop.

Cursor

Cursor supports MCP via the same JSON shape as Claude Desktop. In Settings → Cursor MCP, add:

{
  "mcpServers": {
    "subengine": {
      "transport": {
        "type": "streamable-http",
        "url": "https://mcp.oluwadunsin.dev/mcp",
        "headers": { "X-Api-Key": "<your merchant api key>" }
      }
    }
  }
}

Restart Cursor to pick up the change.

Codex CLI

codex mcp add subengine \
  --transport streamable-http \
  --url https://mcp.oluwadunsin.dev/mcp \
  --header "X-Api-Key: <your merchant api key>"

Verify:

codex mcp list

You should see subengine alongside any other MCP servers you have. New Codex sessions will surface the tools automatically.

MCP Inspector

The reference exploration tool. Great for smoke-testing before pointing a “real” client at the server.

npx @modelcontextprotocol/inspector

In the UI:

• Transport type: Streamable HTTP
• URL: https://mcp.oluwadunsin.dev/mcp
• Custom header: X-Api-Key: <your merchant api key>

Click Connect. Explore the Tools, Resources, and Prompts tabs. Try compute_metric with metric: mrr, or read plans://all.

Verifying by hand

If you’d rather curl:

# health probe (no auth)
curl -sS https://mcp.oluwadunsin.dev/health

# initialize handshake
curl -sS -D /tmp/h.txt -X POST https://mcp.oluwadunsin.dev/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "X-Api-Key: <your key>" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"0"}}}'

SESSION=$(grep -i mcp-session-id /tmp/h.txt | awk '{print $2}' | tr -d '\r\n')

curl -sS -X POST https://mcp.oluwadunsin.dev/mcp \
  -H "Content-Type: application/json" -H "Accept: application/json, text/event-stream" \
  -H "X-Api-Key: <your key>" -H "Mcp-Session-Id: $SESSION" \
  -d '{"jsonrpc":"2.0","method":"notifications/initialized"}'

curl -sS -X POST https://mcp.oluwadunsin.dev/mcp \
  -H "Content-Type: application/json" -H "Accept: application/json, text/event-stream" \
  -H "X-Api-Key: <your key>" -H "Mcp-Session-Id: $SESSION" \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

You should get a JSON response listing all 15 tools.