diff --git a/test/e2e/live/rebuild-hermes-env.ts b/test/e2e/live/rebuild-hermes-env.ts
index 8a46800d653..ea99bf81ba8 100644
--- a/test/e2e/live/rebuild-hermes-env.ts
+++ b/test/e2e/live/rebuild-hermes-env.ts
@@ -15,6 +15,18 @@ export interface RebuildHermesBaseReusePlan {
   childEnv: NodeJS.ProcessEnv;
 }
 
+/** Supply the current Discord credential when rebuild replaces the legacy provider. */
+export function buildRebuildHermesRecreateEnv(
+  discordBotToken: string,
+  baseImageEnv: NodeJS.ProcessEnv = {},
+): NodeJS.ProcessEnv {
+  return {
+    ...baseImageEnv,
+    DISCORD_BOT_TOKEN: discordBotToken,
+    NEMOCLAW_REBUILD_VERBOSE: "1",
+  };
+}
+
 /** Select the normal lane's exact phase 1 image under a test-owned local alias. */
 export function planRebuildHermesBaseReuse(
   staleBaseMode: boolean,
diff --git a/test/e2e/live/rebuild-hermes.test.ts b/test/e2e/live/rebuild-hermes.test.ts
index 5beb2cb9642..0cbe09346c6 100644
--- a/test/e2e/live/rebuild-hermes.test.ts
+++ b/test/e2e/live/rebuild-hermes.test.ts
@@ -45,7 +45,11 @@ import {
   createRebuildHermesCronRestoreFixture,
   hermesRuntimeExecArgs,
 } from "./rebuild-hermes-cron-restore.ts";
-import { buildRebuildHermesChildEnv, planRebuildHermesBaseReuse } from "./rebuild-hermes-env.ts";
+import {
+  buildRebuildHermesChildEnv,
+  buildRebuildHermesRecreateEnv,
+  planRebuildHermesBaseReuse,
+} from "./rebuild-hermes-env.ts";
 import { ensureRebuildHermesHostTools, hermesApiTokenDigest } from "./rebuild-hermes-host-tools.ts";
 import {
   cleanupTrackedRebuildHermesImage,
@@ -1107,10 +1111,11 @@ test(STALE_BASE_REBUILD
   );
   await artifacts.writeJson("phase-5-inference-route-before-rebuild.json", routeBeforeRebuild);
   progress.phase("rebuild the Hermes sandbox");
-  const rebuildEnv = testEnv(undefined, {
-    NEMOCLAW_REBUILD_VERBOSE: "1",
-    ...baseReusePlan?.childEnv,
-  });
+  const rebuildEnv = testEnv(
+    undefined,
+    buildRebuildHermesRecreateEnv(DISCORD_FAKE_TOKEN, baseReusePlan?.childEnv),
+  );
+  expect(rebuildEnv.DISCORD_BOT_TOKEN).toBe(DISCORD_FAKE_TOKEN);
   expect(rebuildEnv).not.toHaveProperty("NVIDIA_INFERENCE_API_KEY");
   expect(rebuildEnv).not.toHaveProperty("COMPATIBLE_API_KEY");
   expect(rebuildEnv).not.toHaveProperty("NVIDIA_API_KEY");
diff --git a/test/e2e/support/rebuild-hermes-env.test.ts b/test/e2e/support/rebuild-hermes-env.test.ts
index 9d036b039ff..e7a97d3e50c 100644
--- a/test/e2e/support/rebuild-hermes-env.test.ts
+++ b/test/e2e/support/rebuild-hermes-env.test.ts
@@ -5,6 +5,7 @@ import { describe, expect, it } from "vitest";
 import type { SandboxBaseImageResolutionMetadata } from "../../../src/lib/sandbox-base-image/types";
 import {
   buildRebuildHermesChildEnv,
+  buildRebuildHermesRecreateEnv,
   planRebuildHermesBaseReuse,
 } from "../live/rebuild-hermes-env.ts";
 
@@ -99,4 +100,24 @@ describe("rebuild-Hermes base reuse", () => {
     expect(childEnv.NVIDIA_INFERENCE_API_KEY).toBeUndefined();
     expect(childEnv.BUILDX_BUILDER).toBeUndefined();
   });
+
+  it("forwards the Discord credential needed to replace the legacy rebuild provider (#10155)", () => {
+    const childEnv = buildRebuildHermesChildEnv(
+      {
+        COMPATIBLE_API_KEY: "must-not-reach-child",
+        NVIDIA_API_KEY: "must-not-reach-child",
+        NVIDIA_INFERENCE_API_KEY: "must-not-reach-child",
+      },
+      buildRebuildHermesRecreateEnv("fixture-discord-token", {
+        NEMOCLAW_HERMES_SANDBOX_BASE_IMAGE_REF: preparedRef,
+      }),
+    );
+
+    expect(childEnv.DISCORD_BOT_TOKEN).toBe("fixture-discord-token");
+    expect(childEnv.NEMOCLAW_HERMES_SANDBOX_BASE_IMAGE_REF).toBe(preparedRef);
+    expect(childEnv.NEMOCLAW_REBUILD_VERBOSE).toBe("1");
+    expect(childEnv.COMPATIBLE_API_KEY).toBeUndefined();
+    expect(childEnv.NVIDIA_API_KEY).toBeUndefined();
+    expect(childEnv.NVIDIA_INFERENCE_API_KEY).toBeUndefined();
+  });
 });