diff --git a/internal/dev-entrypoint/cloud-web-proxy.mjs b/internal/dev-entrypoint/cloud-web-proxy.mjs
index 8ccfb6e5..8bb66c7a 100644
--- a/internal/dev-entrypoint/cloud-web-proxy.mjs
+++ b/internal/dev-entrypoint/cloud-web-proxy.mjs
@@ -76,6 +76,14 @@ export function proxyCloudApiRequest({
     let timeout = null;
     let streamTransformEnded = false;
 
+    const endStreamTransform = () => {
+      if (!streamTransformEnded && streamTransform?.end) {
+        streamTransformEnded = true;
+        return streamTransform.end();
+      }
+      return null;
+    };
+
     const settle = (callback, value) => {
       if (settled) return;
       settled = true;
@@ -107,10 +115,7 @@ export function proxyCloudApiRequest({
             writeStreamOutput(response, streamTransform?.write ? streamTransform.write(chunk) : chunk);
           });
           upstreamResponse.on("end", () => {
-            if (!streamTransformEnded && streamTransform?.end) {
-              streamTransformEnded = true;
-              writeStreamOutput(response, streamTransform.end());
-            }
+            writeStreamOutput(response, endStreamTransform());
             response.end();
             settle(resolve, { statusCode: upstreamStatusCode, streaming: true, streamTransformStats: streamTransform?.stats });
           });
@@ -123,14 +128,15 @@ export function proxyCloudApiRequest({
             settle(reject, error);
           });
           upstreamResponse.on("close", () => {
-            if (!streamTransformEnded && streamTransform?.end) {
-              streamTransformEnded = true;
-              writeStreamOutput(response, streamTransform.end());
-            }
+            writeStreamOutput(response, endStreamTransform());
             if (!response.writableEnded) response.end();
             settle(resolve, { statusCode: upstreamStatusCode, streaming: true, streamTransformStats: streamTransform?.stats });
           });
-          response.on("close", () => upstream.destroy());
+          response.on("close", () => {
+            endStreamTransform();
+            upstream.destroy();
+            settle(resolve, { statusCode: upstreamStatusCode, streaming: true, errorCode: "client_closed", streamTransformStats: streamTransform?.stats });
+          });
           return;
         }
 
diff --git a/internal/dev-entrypoint/cloud-web-proxy.test.mjs b/internal/dev-entrypoint/cloud-web-proxy.test.mjs
index 7ff21ff9..90effc2a 100644
--- a/internal/dev-entrypoint/cloud-web-proxy.test.mjs
+++ b/internal/dev-entrypoint/cloud-web-proxy.test.mjs
@@ -144,6 +144,62 @@ test("cloud web proxy does not reject after SSE headers are already sent", async
   }
 });
 
+test("cloud web proxy resolves stream transform stats when the client closes SSE", async () => {
+  const upstream = createServer((request, response) => {
+    request.resume();
+    response.writeHead(200, { "content-type": "text/event-stream; charset=utf-8" });
+    response.write('data: {"directory":"/workspace","payload":{"type":"session.status"}}\n\n');
+  });
+  await listen(upstream);
+
+  let proxyResult = null;
+  const transform = {
+    stats: { enabled: true, writes: 0, ended: false },
+    write(chunk) {
+      this.stats.writes += 1;
+      return chunk;
+    },
+    end() {
+      this.stats.ended = true;
+      return "";
+    }
+  };
+  const proxy = createServer((request, response) => {
+    const url = new URL(request.url || "/", "http://cloud-web.local");
+    proxyCloudApiRequest({
+      target: new URL(url.pathname + url.search, serverUrl(upstream)),
+      request,
+      response,
+      timeoutMs: 1000,
+      forceStream: true,
+      streamTransform: transform
+    }).then((result) => {
+      proxyResult = result;
+    }).catch((error) => response.destroy(error));
+  });
+  await listen(proxy);
+
+  try {
+    const response = await fetch(`${serverUrl(proxy)}/global/event`, {
+      headers: { accept: "text/event-stream" }
+    });
+    assert.equal(response.status, 200);
+    const reader = response.body.getReader();
+    const first = await reader.read();
+    assert.equal(first.done, false);
+    await reader.cancel();
+    await waitFor(() => proxyResult !== null, "expected proxy result after client close");
+
+    assert.equal(proxyResult.statusCode, 200);
+    assert.equal(proxyResult.streaming, true);
+    assert.equal(proxyResult.errorCode, "client_closed");
+    assert.deepEqual(proxyResult.streamTransformStats, { enabled: true, writes: 1, ended: true });
+  } finally {
+    await close(proxy);
+    await close(upstream);
+  }
+});
+
 test("cloud web proxy buffers normal JSON and sets content-length", async () => {
   const upstream = createServer((request, response) => {
     request.resume();
@@ -189,6 +245,15 @@ function close(server) {
   });
 }
 
+async function waitFor(predicate, message, { timeoutMs = 500, intervalMs = 10 } = {}) {
+  const deadline = Date.now() + timeoutMs;
+  while (Date.now() < deadline) {
+    if (predicate()) return;
+    await new Promise((resolve) => setTimeout(resolve, intervalMs));
+  }
+  assert.fail(message);
+}
+
 function serverUrl(server) {
   const address = server.address();
   return `http://127.0.0.1:${address.port}`;
diff --git a/internal/dev-entrypoint/cloud-web-runtime.test.mjs b/internal/dev-entrypoint/cloud-web-runtime.test.mjs
index ff4a24b2..573a9431 100644
--- a/internal/dev-entrypoint/cloud-web-runtime.test.mjs
+++ b/internal/dev-entrypoint/cloud-web-runtime.test.mjs
@@ -825,6 +825,88 @@ test("cloud web OpenCode proxy emits bounded OTLP span", async () => {
   }
 });
 
+test("cloud web OpenCode event stream emits rewrite OTLP stats when the client closes", async () => {
+  const otelBodies = [];
+  const otel = createServer(async (request, response) => {
+    let body = "";
+    for await (const chunk of request) body += chunk;
+    otelBodies.push(JSON.parse(body));
+    response.writeHead(200, { "content-type": "application/json" });
+    response.end("{}\n");
+  });
+  await listen(otel);
+  const restoreEnv = withEnv({ OTEL_EXPORTER_OTLP_TRACES_ENDPOINT: `${serverUrl(otel)}/v1/traces` });
+
+  const cloudApi = createServer((request, response) => {
+    request.resume();
+    response.writeHead(200, { "content-type": "application/json" });
+    response.end(JSON.stringify({ authenticated: request.headers.cookie === "hwlab_session=session-a" }));
+  });
+  const opencodeResponses = [];
+  const opencode = createServer((request, response) => {
+    request.resume();
+    opencodeResponses.push(response);
+    response.writeHead(200, { "content-type": "text/event-stream; charset=utf-8" });
+    response.write('data: {"directory":"/workspace","payload":{"type":"session.status","properties":{"sessionID":"ses_1"}}}\n\n');
+  });
+  await listen(cloudApi);
+  await listen(opencode);
+
+  const cloudWeb = createCloudWebServer({
+    serviceId: "hwlab-cloud-web",
+    roots: [],
+    cloudApiBaseUrl: serverUrl(cloudApi),
+    cloudApiProxyTimeoutMs: 1000,
+    opencodeUpstreamUrl: serverUrl(opencode),
+    opencodeProxyHost: "127.0.0.1",
+    opencodeProxyTimeoutMs: 1000,
+    opencodeUsername: "oc_user",
+    opencodePassword: "oc_password",
+    opencodeEventDirectoryRewrite: { from: "/workspace", to: "/" },
+    healthPayload: () => ({ status: "ok" }),
+    sendJson(response, statusCode, body) {
+      const payload = JSON.stringify(body);
+      response.writeHead(statusCode, { "content-type": "application/json", "content-length": Buffer.byteLength(payload) });
+      response.end(payload);
+    }
+  });
+  await listen(cloudWeb);
+
+  try {
+    const response = await fetch(`${serverUrl(cloudWeb)}/global/event`, {
+      headers: { accept: "text/event-stream", cookie: "hwlab_session=session-a" }
+    });
+    assert.equal(response.status, 200);
+    const reader = response.body.getReader();
+    const first = await reader.read();
+    assert.equal(first.done, false);
+    const text = new TextDecoder().decode(first.value);
+    assert.match(text, /"directory":"\/"/u);
+    await reader.cancel();
+
+    await waitFor(() => otelBodies.length > 0, "expected OpenCode event stream OTel span");
+    const spans = otelBodies.flatMap((body) => body.resourceSpans?.flatMap((resourceSpan) => resourceSpan.scopeSpans?.flatMap((scopeSpan) => scopeSpan.spans ?? []) ?? []) ?? []);
+    const span = spans.find((item) => item.name === "opencode.proxy.request");
+    assert.ok(span, "expected opencode.proxy.request span");
+    const attrs = new Map((span.attributes ?? []).map((entry) => [entry.key, entry.value?.stringValue ?? entry.value?.intValue ?? entry.value?.boolValue]));
+    assert.equal(attrs.get("http.route"), "/global/event");
+    assert.equal(attrs.get("opencode.proxy.streaming"), true);
+    assert.equal(attrs.get("opencode.proxy.sse.directory_rewrite_enabled"), true);
+    assert.equal(attrs.get("opencode.proxy.sse.directory_rewrite_from"), "/workspace");
+    assert.equal(attrs.get("opencode.proxy.sse.directory_rewrite_to"), "/");
+    assert.equal(attrs.get("opencode.proxy.sse.directory_rewrite_data_lines"), "1");
+    assert.equal(attrs.get("opencode.proxy.sse.directory_rewrite_events"), "1");
+    assert.equal(attrs.get("opencode.proxy.sse.directory_rewrite_json_errors"), "0");
+  } finally {
+    for (const response of opencodeResponses) response.destroy();
+    restoreEnv();
+    await close(cloudWeb);
+    await close(opencode);
+    await close(cloudApi);
+    await close(otel);
+  }
+});
+
 test("cloud web OpenCode proxy accepts short-lived tickets minted by the shell", async () => {
   const restoreEnv = withEnv({
     HWLAB_CLOUD_WEB_DISPLAY_TIME_ZONE: "Asia/Shanghai",