diff --git a/src/web-search/exa-executor.ts b/src/web-search/exa-executor.ts
index 0f6b0f6b79..88ae0d8414 100644
--- a/src/web-search/exa-executor.ts
+++ b/src/web-search/exa-executor.ts
@@ -10,9 +10,10 @@
  */
 import { fetchWithResetRetry } from "../lib/upstream-retry";
 import { signalWithTimeout } from "../lib/abort";
+import { readBoundedResponseBytes } from "../lib/bounded-body";
 import { sidecarEnter } from "../lib/sidecar-tracker";
 import { redactSecretString } from "../lib/redact";
-import type { WebSearchSource } from "./parse";
+import { MAX_SIDECAR_RESPONSE_BYTES, type WebSearchSource } from "./parse";
 import type { SidecarOutcome, SidecarSettings } from "./executor";
 
 const EXA_SEARCH_URL = "https://api.exa.ai/search";
@@ -47,13 +48,26 @@ export async function runExaWebSearch(
       }),
       { abortSignal: linkedSignal.signal, label: "exa-web-search-sidecar" },
     );
+    const bounded = await readBoundedResponseBytes(res, {
+      maxBytes: MAX_SIDECAR_RESPONSE_BYTES,
+      signal: linkedSignal.signal,
+    });
+    if (bounded.oversized) {
+      const prefix = res.ok ? "exa sidecar response" : `exa sidecar HTTP ${res.status} response`;
+      return { text: "", sources: [], error: `${prefix} exceeded byte bound` };
+    }
+    const text = new TextDecoder("utf-8", { fatal: true }).decode(bounded.bytes);
     if (!res.ok) {
-      const t = await res.text().catch(() => "");
       // Scrub BEFORE truncating: slicing first can cut the literal key at the
       // boundary, leaving an unscrubbable key prefix in the surviving text.
-      return { text: "", sources: [], error: `exa sidecar HTTP ${res.status}: ${scrub(t).slice(0, 200)}` };
+      return { text: "", sources: [], error: `exa sidecar HTTP ${res.status}: ${scrub(text).slice(0, 200)}` };
+    }
+    let payload: unknown = null;
+    try {
+      payload = JSON.parse(text);
+    } catch {
+      // The mapper owns the stable malformed/empty JSON outcome.
     }
-    const payload = await res.json().catch(() => null);
     return mapExaSearchResponse(payload);
   } catch (e) {
     const kind = e instanceof Error && e.name === "TimeoutError" ? "timeout" : "connect_error";
diff --git a/tests/exa-web-search.test.ts b/tests/exa-web-search.test.ts
index a47aaa442d..19462bdd05 100644
--- a/tests/exa-web-search.test.ts
+++ b/tests/exa-web-search.test.ts
@@ -6,6 +6,7 @@ import { runWithWebSearch, type WebSearchLoopDeps } from "../src/web-search/loop
 import { createTestTranslatorBudget } from "./helpers/translator-budget";
 import type { AdapterEvent, ProviderAdapter } from "../src/adapters/base";
 import type { OcxConfig, OcxProviderConfig } from "../src/types";
+import { MAX_SIDECAR_RESPONSE_BYTES } from "../src/web-search/parse";
 
 const routed: OcxProviderConfig = { adapter: "openai-chat", baseUrl: "https://routed.test/v1", apiKey: "k" };
 function config(overrides: Partial<OcxConfig> = {}): OcxConfig {
@@ -98,6 +99,28 @@ describe("runExaWebSearch key hygiene (canary)", () => {
       globalThis.fetch = realFetch;
     }
   });
+
+  test.each([
+    ["success", 200],
+    ["error", 500],
+  ] as const)("oversized %s body is rejected and cancelled", async (_branch, status) => {
+    let bodyCancelled = false;
+    const body = new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(new Uint8Array(MAX_SIDECAR_RESPONSE_BYTES + 1).fill(0x61));
+      },
+      cancel() { bodyCancelled = true; },
+    });
+    const realFetch = globalThis.fetch;
+    globalThis.fetch = (async () => new Response(body, { status })) as typeof fetch;
+    try {
+      const out = await runExaWebSearch("q", "key-1", { model: "m", reasoning: "low", timeoutMs: 5000, describeImages: false });
+      expect(out.error).toContain("byte bound");
+      expect(bodyCancelled).toBe(true);
+    } finally {
+      globalThis.fetch = realFetch;
+    }
+  });
 });
 
 describe("planWebSearch exa arm (L9)", () => {