// src/app.module.ts
McpModule.forRoot({
  name: 'dummy-nest-mcp',
  version: '0.1.0',
  // Stateful Streamable HTTP: one McpServer / one session spans the whole
  // connection, so `initialize` and every tool call share an `mcp-session-id`.
  // Without this combo (stateless mode, or no propagated session) each request
  // stands alone — every tool call is its own session and identify() has no
  // stable session to attribute events to.
  transport: McpTransportType.STREAMABLE_HTTP,
  streamableHttp: { enableJsonResponse: true },
  serverMutator: instrumentationMutator, // <- the hook @posthog/mcp plugs into
})

// src/posthog.ts
export const instrumentationMutator = (server) => {
  instrument(server, posthog, { logger, identify });
  return server;
};

npm install
cp .env.example .env   # then put your key in .env

npm start
# -> server.ready http://localhost:3000/mcp

B=http://localhost:3000/mcp
H='Accept: application/json, text/event-stream'

# initialize → grab the session id from the response header
SID=$(curl -s -D /tmp/h.txt -o /dev/null -H "$H" -H 'Content-Type: application/json' -X POST "$B" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"curl","version":"1.0.0"}}}'; \
  grep -i '^mcp-session-id:' /tmp/h.txt | awk '{print $2}' | tr -d '\r')

curl -s -H "$H" -H 'Content-Type: application/json' -H "mcp-session-id: $SID" -X POST "$B" \
  -d '{"jsonrpc":"2.0","method":"notifications/initialized"}'

curl -s -H "$H" -H 'Content-Type: application/json' -H "mcp-session-id: $SID" -X POST "$B" \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"get_trends","arguments":{"event":"pageview","days":3}}}'

{
  "mcpServers": {
    "dummy-nest-mcp": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "http://localhost:3000/mcp", "--transport", "http-only"]
    }
  }
}