> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getmcpulse.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Serving over HTTP

> Streamable HTTP builds a fresh McpServer per request. Wrap inside the factory, not around a long-lived instance.

A streamable-HTTP server builds a **new `McpServer` for every request**, so there is no long-lived instance to wrap. Wrap it inside the factory instead, beside the tool registration:

```ts theme={null}
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { watch } from "@mcpulse/sdk";

function createServer() {
  const server = new McpServer({ name: "my-server", version: "1.0.0" });

  // … your registerTool calls …

  return watch(server, { key: process.env.MCPULSE_KEY });
}
```

`watch` returns the same server, so `return watch(…)` is the whole change.

## Calling watch per request is expected and cheap

This is the part that looks wrong and is not. The session and its buffer are held **per process**, shared by every `watch()` in it that reports to the same place — so calling `watch()` a thousand times does not open a thousand sessions.

Without that sharing, each request would open a session of its own, no two calls would ever land in the same session, and **no retry could ever be detected**. First-call success would read 100% forever, which is worse than reading nothing.

<Warning>
  Do not generate your own session id per request and pass it in. There is no option to do so, deliberately — the shared stream is what keeps the session-scoped metrics honest.
</Warning>

## Wrapping the outer HTTP app does nothing

MCPulse instruments the **MCP server**, not your HTTP framework. It hooks `initialize` and `tools/call` on the low-level protocol server, which is where the tool name, the outcome and the result size actually are. There is nothing useful to read at the Express or Hono layer.

## Related

* [Serving over stdio](/sdk/stdio)
* [Sessions](/metrics/sessions) — why the session boundary matters
* [First-call success](/metrics/first-call-success) — what breaks if sessions fragment