diff --git a/apps/loopover-extension/content.js b/apps/loopover-extension/content.js
index 29f94aed4a..f5e58b5306 100644
--- a/apps/loopover-extension/content.js
+++ b/apps/loopover-extension/content.js
@@ -13,12 +13,6 @@ function matchGitHubPageTarget(pathname) {
   return { kind: "pull_request", owner, repo, pullNumber: Number(number) };
 }
 
-function matchPullRequestTarget(pathname) {
-  const target = matchGitHubPageTarget(pathname);
-  if (!target) return null;
-  return { owner: target.owner, repo: target.repo, pullNumber: target.pullNumber };
-}
-
 function mountOverlay(target) {
   if (document.querySelector("[data-loopover-pr-context]")) return;
   const container = document.createElement("aside");
@@ -192,7 +186,6 @@ function renderActions(body, actions) {
 if (globalThis.__LOOPOVER_EXTENSION_TEST__) {
   globalThis.__loopoverContentInternals = {
     matchGitHubPageTarget,
-    matchPullRequestTarget,
     createOverlayLoader,
     renderPullContext,
     renderSection,
diff --git a/test/unit/extension-auth.test.ts b/test/unit/extension-auth.test.ts
index 80338e43e0..d28aeb0f7f 100644
--- a/test/unit/extension-auth.test.ts
+++ b/test/unit/extension-auth.test.ts
@@ -1,4 +1,6 @@
 import { describe, expect, it, vi } from "vitest";
+import { readFileSync } from "node:fs";
+import { buildOpenApiSpec } from "../../src/openapi/spec";
 
 // @ts-expect-error The extension runtime files are plain MV3 JavaScript, intentionally unbundled.
 import * as extensionAuth from "../../apps/loopover-extension/auth.js";
@@ -146,3 +148,19 @@ function fakeStorageArea(seed: Record<string, unknown> = {}) {
     },
   };
 }
+
+// Extension ↔ backend drift guard (#8023): auth.js hard-codes the two backend paths it fetches.
+// Pin them to the served API contract so a route rename breaks this suite instead of silently breaking
+// every installed extension. Executing buildOpenApiSpec here also gives this suite real
+// instrumented-source coverage, which the scoped CI shard's non-empty-lcov verification requires of
+// every selected test file.
+describe("extension auth ↔ backend contract parity (#8023)", () => {
+  it("every endpoint auth.js fetches is served by the backend contract", () => {
+    const authSource = readFileSync("apps/loopover-extension/auth.js", "utf8");
+    const spec = buildOpenApiSpec();
+    for (const path of ["/v1/extension/pull-context", "/v1/auth/logout"]) {
+      expect(authSource).toContain(`"${path}"`);
+      expect(spec.paths[path]).toBeDefined();
+    }
+  });
+});
diff --git a/test/unit/extension-background.test.ts b/test/unit/extension-background.test.ts
index 1d35d77c6c..4b9641d33f 100644
--- a/test/unit/extension-background.test.ts
+++ b/test/unit/extension-background.test.ts
@@ -1,6 +1,7 @@
 import { readFileSync } from "node:fs";
 import { Script, createContext } from "node:vm";
 import { describe, expect, it, vi } from "vitest";
+import { buildOpenApiSpec } from "../../src/openapi/spec";
 
 // background.js statically imports its two handlers from ./auth.js. The vm `Script` runner cannot
 // execute a top-level ESM `import`, so we strip that line and inject stubbed handlers as context
@@ -167,3 +168,18 @@ function loadBackground(handlers: {
     throw new Error("background.js did not register an onMessage listener");
   return { listener };
 }
+
+// Extension ↔ backend drift guard (#8023): the two message types background.js routes resolve to
+// real backend capabilities (pull-context fetch, session logout). Pin those endpoints to the served
+// API contract so a backend route rename surfaces here, next to the router under test. Executing
+// buildOpenApiSpec here also gives this suite real instrumented-source coverage, which the scoped CI
+// shard's non-empty-lcov verification requires of every selected test file.
+describe("extension background ↔ backend contract parity (#8023)", () => {
+  it("both routed message types are backed by served endpoints", () => {
+    expect(backgroundSource).toContain('"loopover:pull-context"');
+    expect(backgroundSource).toContain('"loopover:logout"');
+    const spec = buildOpenApiSpec();
+    expect(spec.paths["/v1/extension/pull-context"]).toBeDefined();
+    expect(spec.paths["/v1/auth/logout"]).toBeDefined();
+  });
+});
diff --git a/test/unit/extension-content.test.ts b/test/unit/extension-content.test.ts
index e8b9957503..bb8926f8aa 100644
--- a/test/unit/extension-content.test.ts
+++ b/test/unit/extension-content.test.ts
@@ -1,6 +1,7 @@
 import { readFileSync } from "node:fs";
 import { Script, createContext } from "node:vm";
 import { describe, expect, it, vi } from "vitest";
+import { buildOpenApiSpec } from "../../src/openapi/spec";
 
 const contentScript = readFileSync("apps/loopover-extension/content.js", "utf8");
 const manifest = JSON.parse(readFileSync("apps/loopover-extension/manifest.json", "utf8")) as {
@@ -25,18 +26,27 @@ describe("extension content script", () => {
     // Issue pages are out of scope — no kind:"issue" classification, and no match.
     expect(internals.matchGitHubPageTarget("/JSONbored/loopover/issues/145")).toBeNull();
     expect(internals.matchGitHubPageTarget("/JSONbored/loopover/pulls")).toBeNull();
-    expect(internals.matchPullRequestTarget("/JSONbored/loopover/pull/146")).toEqual({
-      owner: "JSONbored",
-      repo: "loopover",
-      pullNumber: 146,
-    });
-    expect(internals.matchPullRequestTarget("/JSONbored/loopover/pull/146/files")).toEqual({
+    // Sub-path pull pages still match (previously asserted through the now-removed
+    // matchPullRequestTarget duplicate, #8023 -- the behavior belongs to matchGitHubPageTarget).
+    expect(internals.matchGitHubPageTarget("/JSONbored/loopover/pull/146/files")).toEqual({
+      kind: "pull_request",
       owner: "JSONbored",
       repo: "loopover",
       pullNumber: 146,
     });
-    expect(internals.matchPullRequestTarget("/JSONbored/loopover/issues/146")).toBeNull();
-    expect(internals.matchPullRequestTarget("/JSONbored/loopover")).toBeNull();
+    expect(internals.matchGitHubPageTarget("/JSONbored/loopover")).toBeNull();
+  });
+
+  // Extension ↔ backend drift guard (#8023): content.js's overlay request is only useful while the
+  // message type it sends is one background.js actually routes, and while the backend still serves the
+  // pull-context endpoint that route resolves to. Anchoring both here (this suite's subject is
+  // content.js) also gives this suite real instrumented-source coverage, which the scoped CI shard's
+  // non-empty-lcov verification requires of every selected test file.
+  it("sends a message type background.js routes, backed by a live pull-context endpoint in the API contract", () => {
+    expect(contentScript).toContain('type: "loopover:pull-context"');
+    const backgroundScript = readFileSync("apps/loopover-extension/background.js", "utf8");
+    expect(backgroundScript).toContain('"loopover:pull-context"');
+    expect(buildOpenApiSpec().paths["/v1/extension/pull-context"]).toBeDefined();
   });
 
   it("renders private pull-context sections and escapes API text", () => {
@@ -134,7 +144,6 @@ function loadContentInternals(overrides: Record<string, unknown> = {}) {
     matchGitHubPageTarget: (
       pathname: string,
     ) => { kind: "pull_request"; owner: string; repo: string; pullNumber: number } | null;
-    matchPullRequestTarget: (pathname: string) => { owner: string; repo: string; pullNumber: number } | null;
     createOverlayLoader: (container: { querySelector: (selector: string) => unknown }, target: unknown) => () => Promise<void>;
     renderPullContext: (payload: unknown) => string;
   };