Remove the Start graph warmup attempts and latency probes

apps/cloud/src/env-augment.d.ts

@@ -95,8 +95,6 @@ declare global {
       MCP_REQUEST_STATE_KEY?: string;
       /** Emergency rollback for inbound MCP 2026-07-28 traffic only. */
       MCP_2026_07_28_ENABLED?: string;
-      // Kill switch for the Start server-graph warmup (server.ts).
-      START_GRAPH_WARM?: string;
       NODE_ENV?: string;
 
       // Shared with frontend

apps/cloud/src/server.ts

@@ -103,36 +103,12 @@ export { McpExecutionOwnerDirectoryDO } from "@executor-js/cloudflare/mcp/execut
 // until the in-flight export resolves.
 // ---------------------------------------------------------------------------
 
-const rawFetchHandler = handler.fetch as (
+const fetchHandler = handler.fetch as (
   request: Request,
   env: Env,
   ctx: ExecutionContext,
 ) => Response | Promise<Response>;
 
-// TEMPORARY: does an isolate that already warmed still pay for Start?
-let startEverHandled = false;
-const fetchHandler = async (
-  request: Request,
-  env: Env,
-  ctx: ExecutionContext,
-): Promise<Response> => {
-  const wasWarm = startEverHandled;
-  startEverHandled = true;
-  await scheduler.wait(0);
-  const startedAt = Date.now();
-  const response = await rawFetchHandler(request, env, ctx);
-  await scheduler.wait(0);
-  console.log(
-    JSON.stringify({
-      probe: "start",
-      path: new URL(request.url).pathname,
-      wasWarm,
-      ms: Date.now() - startedAt,
-    }),
-  );
-  return response;
-};
-
 const tracer = trace.getTracer("executor-cloud-worker");
 
 const traceparentValueFor = (spanContext: SpanContext): string =>
@@ -202,79 +178,8 @@ const mcpAgentHandler = makeCloudMcpAgentHandler({
   traceRequest: traceCloudMcpRequest,
 });
 
-// ---------------------------------------------------------------------------
-// Start server-graph warmup
-// ---------------------------------------------------------------------------
-//
-// Page latency was p50 19-49ms daily through 2026-08-16 and 2728ms the day
-// after the 21:20 deploy. Not load: 2026-08-11 served MORE traffic (5.43M vs
-// 4.38M requests) with pages at p50 41ms.
-//
-// What changed is where MCP work runs. The old hibernatable Agent bridge handed
-// `/mcp` to the Durable Object almost immediately; the v2 stack authenticates
-// and dispatches in the worker. `/mcp` returns above without touching
-// `fetchHandler`, so an isolate can serve a lot of MCP traffic and still have
-// never loaded the Start graph. Measured: isolates that served a page request
-// had already served a median of 19 spans across 3 paths — they are reused,
-// they are just cold for Start. The page request then pays `loadEntries`: p50
-// **3.1s**, against p50 33ms for the request's own work and 9-104ms warm. The
-// same bundle in local workerd serves the same path in ~3ms.
-//
-// Warm by REPLAYING A REAL REQUEST through the handler, not by importing the
-// virtual entry ids. Two attempts at the import approach (#1679, #1681) moved
-// nothing in production: `loadEntries` awaits THREE specifiers
-// (`#tanstack-router-entry`, `#tanstack-start-entry`,
-// `#tanstack-start-plugin-adapters`) plus a separately-cached manifest, so
-// warming a subset leaves the request paying for the rest. Driving the real
-// handler populates whatever those caches are, by construction, and cannot
-// drift when Start changes its internals.
-//
-// `/robots.txt` is the cheapest Start-served route. It runs once per isolate,
-// under `waitUntil` so it outlives the request that triggered it, and costs one
-// extra synthetic request per isolate in telemetry.
-// `START_GRAPH_WARM=false` disables it without a deploy.
-// ---------------------------------------------------------------------------
-
-let startGraphWarmupStarted = false;
-
-const warmStartGraph = (env: Env, ctx: ExecutionContext): void => {
-  if (startGraphWarmupStarted) return;
-  if (env.START_GRAPH_WARM === "false") return;
-  startGraphWarmupStarted = true;
-
-  ctx.waitUntil(
-    (async () => {
-      const startedAt = Date.now();
-      // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary; a warmup failure must never affect the request that triggered it
-      try {
-        await fetchHandler(
-          new Request("https://executor.sh/robots.txt", { method: "GET" }),
-          env,
-          ctx,
-        );
-        console.log(JSON.stringify({ probe: "warm", ok: true, ms: Date.now() - startedAt }));
-      } catch {
-        // Advisory only — the request path still loads the graph lazily.
-        startGraphWarmupStarted = false;
-        console.log(
-          JSON.stringify({
-            probe: "warm",
-            ok: false,
-            ms: Date.now() - startedAt,
-          }),
-        );
-      }
-    })(),
-  );
-};
-
 const cloudflareHandler: ExportedHandler<Env> = {
   fetch: async (request, env, ctx) => {
-    // First fetch in this isolate drives one real request through Start in the
-    // background, including for /mcp — MCP traffic is what reaches these
-    // isolates first, and is why they are otherwise never warmed.
-    warmStartGraph(env, ctx);
-
     // Public pages must not enter TanStack Start: its first-request dynamic
     // import loads the entire React + Effect server graph and can take seconds
     // on a cold isolate. Classify and service-bind marketing at the Worker