import { DurableObject } from "cloudflare:workers";import { SpanKind, SpanStatusCode, context, trace, type SpanContext } from "@opentelemetry/api";import {  ATTR_HTTP_REQUEST_METHOD,  ATTR_HTTP_RESPONSE_STATUS_CODE,  ATTR_URL_FULL,  ATTR_URL_PATH,  ATTR_URL_SCHEME,} from "@opentelemetry/semantic-conventions";import * as Sentry from "@sentry/cloudflare";import handler from "@tanstack/react-start/server-entry"; import { isAppOwnedPath, servedByAppPlane } from "./app-paths";import { marketingProxyRequest } from "./edge/marketing";import { passthroughResponse } from "./edge/passthrough";import { makeCloudMcpAgentHandler } from "./mcp/agent-handler";import { classifyMcpPath, prepareMcpOrgScope } from "./mcp/mount";import { parseTraceparent } from "./mcp/traceparent";import { McpSessionDOSqlite as McpSessionDOBase } from "./mcp/session-durable-object";import {  cloudSentryOptions,  captureCause,  otelCorrelationContextFromOpenTelemetrySpan,  SENTRY_EVENT_ID_ATTRIBUTE,  tagCurrentSentryScopeWithOtelContext,} from "./observability";import { browserTracesResponse } from "./observability/browser-traces";import { flushTracerProvider, installTracerProvider } from "./observability/telemetry"; // ---------------------------------------------------------------------------// Durable Object — wrapped with Sentry so DO errors land in Sentry (inits the// client inside the DO isolate, which plain `Sentry.captureException` cannot// do on its own). OTEL is installed through Effect layers (observability/telemetry),// not a global fetch wrapper.// --------------------------------------------------------------------------- export const McpSessionDOSqlite = Sentry.instrumentDurableObjectWithSentry(  cloudSentryOptions,  McpSessionDOBase,); // Orphaned placeholder for the original key-value `McpSessionDO` class (migration// v1). The live MCP session DO is now `McpSessionDOSqlite` (SQLite); the// `MCP_SESSION` binding moved to it. Cloudflare won't delete `McpSessionDO` in the// same deploy that moves its binding, so the class is left unbound and is kept// exported here only to satisfy the migration. It can be removed in a later deploy// (with a `deleted_classes: ["McpSessionDO"]` migration) now that nothing binds it.export class McpSessionDO extends DurableObject {} // Per-org execution rate-limit counter DO (abuse backstop; migration v3,// `EXECUTION_RATE_LIMITER` binding). Plain counter, no Sentry wrapper needed:// its callers already fail open and report errors themselves.export { ExecutionRateLimiterDO } from "./engine/execution-rate-limit"; export { McpExecutionOwnerDirectoryDO } from "@executor-js/cloudflare/mcp/execution-owner-directory"; // ---------------------------------------------------------------------------// Worker fetch handler//// We open a single `http.server <METHOD>` span at the worker boundary using// the same WebTracerProvider that `observability/telemetry.ts` already installs for// Effect-driven spans. This restores the per-request envelope span that was// previously emitted by `@microlabs/otel-cf-workers` and lost in the alchemy// migration — without the OTel-SDK version-conflict that package would now// drag in (it pins `@opentelemetry/otlp-* ^0.200.0`, we ship ^0.214.0).//// App-owned paths (/api/* and /.well-known/* — see app-paths.ts) get their// `http.server` span from Effect's HttpMiddleware tracer. `/mcp` is dispatched// directly and uses `traceCloudMcpRequest` below so the agent handler can skip// the entire span envelope for negative-cache hits. Other paths keep this// worker span. Wrapping Effect-owned paths here too produced duplicate sibling// spans per request.//// SimpleSpanProcessor exports synchronously at span end but the underlying// `fetch()` to Axiom is fire-and-forget; the Worker may terminate before it// completes. `ctx.waitUntil(flushTracerProvider())` keeps the isolate alive// until the in-flight export resolves.// --------------------------------------------------------------------------- const rawFetchHandler = handler.fetch as (  request: Request,  env: Env,  ctx: ExecutionContext,) => Response | Promise<Response>; /** * Every entry into TanStack Start goes through here so `startGraphEntered` * reflects whether this isolate has already paid the lazy `loadEntries` * import — the cost that dominates a cold page request. */const fetchHandler = (  request: Request,  env: Env,  ctx: ExecutionContext,): Response | Promise<Response> => {  markStartGraphEntered();  return rawFetchHandler(request, env, ctx);}; const tracer = trace.getTracer("executor-cloud-worker"); const traceparentValueFor = (spanContext: SpanContext): string =>  `00-${spanContext.traceId}-${spanContext.spanId}-${(spanContext.traceFlags & 0xff).toString(16).padStart(2, "0")}`; const withTraceparent = (request: Request, spanContext: SpanContext): Request => {  const headers = new Headers(request.headers);  headers.set("traceparent", traceparentValueFor(spanContext));  return new Request(request, { headers });}; const traceCloudMcpRequest = async (  request: Request,  _env: Env,  ctx: ExecutionContext,  handle: (tracedRequest: Request) => Promise<Response>,): Promise<Response> => {  if (!installTracerProvider()) return handle(request);   const url = new URL(request.url);  const inbound = parseTraceparent(request.headers.get("traceparent"), null);  const parentContext = inbound    ? trace.setSpanContext(context.active(), {        traceId: inbound.traceId,        spanId: inbound.spanId,        traceFlags: inbound.traceFlags,        isRemote: true,      })    : context.active();   return tracer.startActiveSpan(    `http.server ${request.method}`,    { kind: SpanKind.SERVER },    parentContext,    async (span) => {      span.setAttribute(ATTR_HTTP_REQUEST_METHOD, request.method);      span.setAttribute(ATTR_URL_FULL, request.url);      span.setAttribute(ATTR_URL_PATH, url.pathname);      span.setAttribute(ATTR_URL_SCHEME, url.protocol.replace(/:$/, ""));      // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary; observe response/error for span status, keep trace export alive after the Agents bridge resolves or rejects      try {        const response = await handle(withTraceparent(request, span.spanContext()));        span.setAttribute(ATTR_HTTP_RESPONSE_STATUS_CODE, response.status);        if (response.status >= 500) {          span.setStatus({ code: SpanStatusCode.ERROR, message: `HTTP ${response.status}` });        }        return response;      } catch (err) {        // oxlint-disable-next-line executor/no-instanceof-error, executor/no-unknown-error-message -- adapter boundary: Cloudflare's fetch callback throws untyped; normalized only for the OTel span record, the original error is rethrown below        const cause = err instanceof Error ? err : String(err);        span.recordException(cause);        // oxlint-disable-next-line executor/no-unknown-error-message -- adapter boundary: same normalization as the recordException line above        const message = typeof cause === "string" ? cause : cause.message;        span.setStatus({ code: SpanStatusCode.ERROR, message });        // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary; preserve original error to Cloudflare runtime        throw err;      } finally {        span.end();        ctx.waitUntil(flushTracerProvider());      }    },  );}; const mcpAgentHandler = makeCloudMcpAgentHandler(); // ---------------------------------------------------------------------------// Isolate lifecycle signals// ---------------------------------------------------------------------------//// The Aug 2026 page-latency hunt kept stalling on one blind spot: every span we// emit starts INSIDE the fetch handler, so nothing could distinguish "this// isolate is cold and paying Start's lazy `loadEntries` import" from "this// isolate came up slowly before our code ran at all". Both look like one slow// span. These three attributes make the distinction queryable:////   executor.isolate.request_seq  - 1 means this request is the isolate's//                                   first; page requests measured 1.04 per//                                   isolate, which is why nearly every one//                                   pays the cold cost.//   executor.start_graph.entered  - whether anything had already driven//                                   TanStack Start in this isolate. /mcp and//                                   the passthrough proxies return before//                                   `fetchHandler`, so an isolate can serve//                                   plenty of traffic and still be cold here.// Measured with a temporary entry-lag probe correlated against `wrangler tail`// event timestamps: a cold isolate (`request_seq` 1) spends **840-1844ms**// coming up before our first line runs, while a reused one spends **0-2ms**.// That startup is invisible to every span we emit, and it sits on top of the// ~3.1s `loadEntries` import — together the 3-5s a signed-in page costs.////   executor.isolate.id           - identifies the isolate itself, so reuse can//                                   be counted directly instead of inferred.//   executor.isolate.age_ms       - ms since this isolate served its first//                                   request.//// The last two exist because the Aug 2026 hunt inferred "isolates stopped being// reused" from a latency cutoff (requests slower than 1s were called cold) and// then built a size-based theory on top of that proxy. The theory was wrong:// reverting the offending packages restored production while moving the// evaluated module closure by 0.02 MB (see scripts/start-closure.mjs). Grouping// by isolate id answers "how many requests did this isolate serve, and were the// slow ones its first?" directly, which no latency threshold can.//// All of it is cheap: two increments, one lazy uuid, and no I/O.let isolateRequestSeq = 0;let startGraphEntered = false;// Minted on first request rather than at module scope: Workers reject random// number generation during global-scope evaluation.let isolateId: string | undefined;let isolateFirstSeenAt = 0; const identifyIsolate = (): { readonly id: string; readonly ageMs: number } => {  if (isolateId === undefined) {    isolateId = crypto.randomUUID();    isolateFirstSeenAt = Date.now();  }  return { id: isolateId, ageMs: Date.now() - isolateFirstSeenAt };}; const markStartGraphEntered = (): void => {  startGraphEntered = true;}; // ---------------------------------------------------------------------------// Serving `/api/*` without entering TanStack Start.// ---------------------------------------------------------------------------//// Everything under `/api` is the Effect app (`ExecutorApp.make`'s web handler)// and uses no part of the router, React, or SSR. But it was dispatched from a// Start *request middleware*, so reaching it meant paying Start's lazy// `loadEntries` import of the whole server graph first. Measured on production// 2026-08-19, splitting `/api/*` by whether the isolate had already loaded that// graph: warm p50 **186ms**, cold p50 **2129ms**, with 28% of API requests cold.// The dashboard fires many `/api/*` calls in parallel and waits for the slowest,// so that cold tail is what the app actually feels like.//// So `/api` joins marketing, `/docs`, the PostHog proxy and `/mcp` at the Worker// entry: classify and dispatch before anything touches Start. The evaluated// closure for an API request drops from the full Start graph to the Worker's own// (see `scripts/start-closure.mjs`).//// `servedByAppPlane` (./app-paths) decides which paths qualify — two under// `/api` are claimed by Start's middleware first and must keep their old route. // Instantiated on the first request that needs it and memoized per isolate,// mirroring `start.ts`'s `getApp`. The import stays dynamic so an isolate that// only serves pages or proxies never evaluates the app graph at all.let appPlane: ReturnType<typeof import("./app").cloudApiHandler> | undefined;let appGraphEntered = false; const getAppPlane = async (): Promise<NonNullable<typeof appPlane>> => {  if (appPlane === undefined) {    const { cloudApiHandler } = await import("./app");    appPlane = cloudApiHandler();    appGraphEntered = true;  }  return appPlane;}; const cloudflareHandler: ExportedHandler<Env> = {  fetch: async (request, env, ctx) => {    isolateRequestSeq += 1;     // 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    // entry, before telemetry or fetchHandler touches that graph.    const marketingRequest = marketingProxyRequest(request);    const marketing: Fetcher | undefined = env.MARKETING;    if (marketingRequest && marketing) return marketing.fetch(marketingRequest);     // Same reasoning, same seam: `/docs` and the PostHog proxy forward to an    // external origin and never touch the router, React, or the Effect app.    // Left in Start's middleware they still paid its lazy `loadEntries` import    // first — measured at p50 3.1s on a cold isolate, against p50 33ms for the    // request's own work, on a Worker where 1,666 dispatches spread across    // 1,608 isolates (so nearly every request is cold). Forward before Start.    const passthroughPath = new URL(request.url).pathname;    const passthrough = passthroughResponse(request, passthroughPath);    if (passthrough) return passthrough;     // Browser OTLP ingress — before the server span opens: exporter traffic    // must never trace itself (the browser already excludes /v1/traces from    // its own tracing for the same reason).    const browserTraces = browserTracesResponse(request, env);    if (browserTraces) return browserTraces;    // The MCP dispatch is classified up front, independent of whether    // telemetry installs — an unset `AXIOM_TOKEN` (tracer not installed) must    // never take /mcp requests down with it. See `installTracerProvider`'s    // early return below: the handler invokes it for uncached MCP traffic, and    // this entry invokes it for non-MCP paths.    const url = new URL(request.url);    const mcpRoute = classifyMcpPath(url.pathname);    if (mcpRoute?.kind === "mcp") {      // The Cloudflare Agents MCP bridge needs the platform ExecutionContext      // to pass authenticated session props into the hibernatable DO.      // Discovery docs still flow through the app-level MCP envelope.      const forwarded = prepareMcpOrgScope(request);      // /mcp leaves the Effect app for the Agents bridge, so no downstream      // HttpMiddleware.tracer opens the request envelope — this worker span is      // THE `http.server` span for MCP traffic, and its context is stamped onto      // the forwarded traceparent so the agent handler and session DO parent      // under it instead of exporting orphaned roots.      return traceCloudMcpRequest(forwarded, env, ctx, (tracedRequest) =>        Promise.resolve(mcpAgentHandler(tracedRequest, env, ctx)),      );    }    const tracingInstalled = installTracerProvider();    // Join the caller's W3C trace when the request carries one — the web UI    // sends traceparent on every API fetch, so the browser's spans and this    // request share one trace id end to end. Same parsing the DO path does    // in session-durable-object.ts.    const inbound = parseTraceparent(request.headers.get("traceparent"), null);    const parentContext = inbound      ? trace.setSpanContext(context.active(), {          traceId: inbound.traceId,          spanId: inbound.spanId,          traceFlags: inbound.traceFlags,          isRemote: true,        })      : context.active();    if (!tracingInstalled) {      return fetchHandler(request, env, ctx);    }    // Effect-served paths bring their own http.server span (with traceparent    // join) — a second SERVER span here would duplicate it (the header note).    // What they do NOT cover is the time between this invocation starting and    // the Effect router opening its span (Start dispatch, middleware, lazy    // module graph): during the Aug 2026 regression that gap was seconds of    // invisible wall time. `worker.dispatch` is an INTERNAL parent that    // brackets the whole invocation; Effect's http.server span joins under it    // via the injected traceparent, so gap = dispatch minus server span.    if (isAppOwnedPath(url.pathname)) {      return tracer.startActiveSpan(        "worker.dispatch",        { kind: SpanKind.INTERNAL },        parentContext,        async (span) => {          span.setAttribute(ATTR_HTTP_REQUEST_METHOD, request.method);          span.setAttribute(ATTR_URL_PATH, url.pathname);          const isolate = identifyIsolate();          span.setAttribute("executor.isolate.request_seq", isolateRequestSeq);          span.setAttribute("executor.start_graph.entered", startGraphEntered);          span.setAttribute("executor.isolate.id", isolate.id);          span.setAttribute("executor.isolate.age_ms", isolate.ageMs);          // Which plane served this: "app" skipped the Start graph entirely, so          // `start_graph.entered` says nothing about it. `app_graph.entered`          // is the app-plane analogue - false means this request paid for the          // Effect graph's first evaluation in this isolate.          const appPlaneRequest = servedByAppPlane(url.pathname, request.method);          span.setAttribute("executor.dispatch.plane", appPlaneRequest ? "app" : "start");          if (appPlaneRequest) span.setAttribute("executor.app_graph.entered", appGraphEntered);          // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary; observe response/error for span status, keep the flush alive past the response          try {            const traced = withTraceparent(request, span.spanContext());            const response = appPlaneRequest              ? await (await getAppPlane()).handler(prepareMcpOrgScope(traced))              : await fetchHandler(traced, env, ctx);            span.setAttribute(ATTR_HTTP_RESPONSE_STATUS_CODE, response.status);            return response;          } catch (err) {            // oxlint-disable-next-line executor/no-instanceof-error, executor/no-unknown-error-message -- adapter boundary: Cloudflare's fetch callback throws untyped; normalized only for the OTel span record, the original error is rethrown below            const cause = err instanceof Error ? err : String(err);            span.recordException(cause);            // oxlint-disable-next-line executor/no-unknown-error-message -- adapter boundary: same normalization as the recordException line above            const message = typeof cause === "string" ? cause : cause.message;            span.setStatus({ code: SpanStatusCode.ERROR, message });            // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary; preserve original error to Cloudflare runtime            throw err;          } finally {            span.end();            // The flush still must outlive the request — Effect's            // BatchSpanProcessor ships on a timer.            ctx.waitUntil(flushTracerProvider());          }        },      );    }    return tracer.startActiveSpan(      `http.server ${request.method}`,      { kind: SpanKind.SERVER },      parentContext,      async (span) => {        const otelContext = otelCorrelationContextFromOpenTelemetrySpan(span);        tagCurrentSentryScopeWithOtelContext(otelContext);        span.setAttribute(ATTR_HTTP_REQUEST_METHOD, request.method);        span.setAttribute(ATTR_URL_FULL, request.url);        span.setAttribute(ATTR_URL_PATH, url.pathname);        span.setAttribute(ATTR_URL_SCHEME, url.protocol.replace(/:$/, ""));        // Adapter boundary: Cloudflare's fetch handler is a Promise-based        // callback and the OTel span lifecycle needs to observe both the        // resolved response and any thrown error before `span.end()`. Sentry's        // outer wrapper still captures the exception; we only mark span status.        // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary        try {          if (env.SENTRY_OTEL_VERIFY === "true" && url.pathname === "/__sentry-otel-verify") {            // oxlint-disable-next-line executor/no-error-constructor -- boundary: synthetic verification needs an Error payload for Sentry grouping            const eventId = captureCause(new Error("sentry otel verification"), otelContext) ?? "";            if (eventId) span.setAttribute(SENTRY_EVENT_ID_ATTRIBUTE, eventId);            span.setAttribute("sentry_otel.verify", true);            span.setAttribute(ATTR_HTTP_RESPONSE_STATUS_CODE, 500);            span.setStatus({ code: SpanStatusCode.ERROR });            return Response.json(              {                sentryEventId: eventId,                otelTraceId: otelContext?.traceId ?? "",                otelSpanId: otelContext?.spanId ?? "",              },              { status: 500 },            );          }          const response = await fetchHandler(request, env, ctx);          span.setAttribute(ATTR_HTTP_RESPONSE_STATUS_CODE, response.status);          if (response.status >= 500) {            span.setStatus({ code: SpanStatusCode.ERROR, message: `HTTP ${response.status}` });          }          return response;        } catch (err) {          // Record the exception itself, not just the status bit: without it          // these spans are ERROR with zero diagnostic content.          // oxlint-disable-next-line executor/no-instanceof-error, executor/no-unknown-error-message -- adapter boundary: Cloudflare's fetch callback throws untyped; normalized only for the OTel span record, the original error is rethrown below          const cause = err instanceof Error ? err : String(err);          span.recordException(cause);          // oxlint-disable-next-line executor/no-unknown-error-message -- adapter boundary: same normalization as the recordException line above          const message = typeof cause === "string" ? cause : cause.message;          span.setStatus({ code: SpanStatusCode.ERROR, message });          // oxlint-disable-next-line executor/no-try-catch-or-throw -- adapter boundary; preserve original error to Cloudflare runtime          throw err;        } finally {          span.end();          ctx.waitUntil(flushTracerProvider());        }      },    );  },}; export default Sentry.withSentry(cloudSentryOptions, cloudflareHandler);