diff --git a/src/queue/processors.ts b/src/queue/processors.ts
index b630b62717..b44982356c 100644
--- a/src/queue/processors.ts
+++ b/src/queue/processors.ts
@@ -334,7 +334,7 @@ import {
   type ContributorProfile,
 } from "../signals/engine";
 import { isDuplicateClusterWinnerByClaim } from "../signals/duplicate-winner";
-import { buildUnifiedReviewDiff } from "../review/review-diff";
+import { buildUnifiedReviewDiff, totalAddedLineCount } from "../review/review-diff";
 import { estimateReviewEffort } from "../review/review-effort";
 import { buildUnifiedCommentBody } from "../review/unified-comment-bridge";
 import { randomUUID } from "node:crypto";
@@ -6334,6 +6334,8 @@ export async function resolveAutoReviewSkipForPullRequest(
     deliveryId: string;
     headSha: string | null | undefined;
     changedPaths?: readonly string[] | undefined;
+    addedLineCount?: number | undefined;
+    changedFileCount?: number | undefined;
   },
 ): Promise<{ skipReason: string | null; reviewManifest: FocusManifest | null }> {
   if (args.authorBlacklisted || args.isFrozenForManualReview) {
@@ -6349,6 +6351,8 @@ export async function resolveAutoReviewSkipForPullRequest(
     title: args.pr.title,
     labels: args.pr.labels ?? [],
     changedPaths: args.changedPaths ?? [],
+    addedLineCount: args.addedLineCount ?? 0,
+    changedFileCount: args.changedFileCount ?? 0,
     baseRef: args.pr.baseRef ?? null,
     reviewedCommitCount,
   });
@@ -8143,7 +8147,10 @@ async function maybePublishPrPublicSurface(
       pr.labels.some((label) => label.toLowerCase() === manualReviewLabel.toLowerCase());
     let reviewManifestForAutoReview: FocusManifest | null = null;
     let autoReviewSkipReason: string | null = null;
-    const autoReviewChangedPaths = (await getReviewFiles()).map((file) => file.path);
+    const autoReviewFiles = await getReviewFiles();
+    const autoReviewChangedPaths = autoReviewFiles.map((file) => file.path);
+    const autoReviewAddedLineCount = totalAddedLineCount(autoReviewFiles);
+    const autoReviewChangedFileCount = autoReviewFiles.length;
     ({
       skipReason: autoReviewSkipReason,
       reviewManifest: reviewManifestForAutoReview,
@@ -8157,6 +8164,8 @@ async function maybePublishPrPublicSurface(
       deliveryId: webhook.deliveryId,
       headSha: advisory.headSha ?? null,
       changedPaths: autoReviewChangedPaths,
+      addedLineCount: autoReviewAddedLineCount,
+      changedFileCount: autoReviewChangedFileCount,
     }));
     // review.changed_files_summary (#1957) + review.effort_score (#1955): both deterministic, no-AI — resolve
     // them here, UNCONDITIONALLY, rather than inside the aiReviewWillRun-gated closure below. These sections
diff --git a/src/review/review-diff.ts b/src/review/review-diff.ts
index e3ebd8d211..02661d3ca2 100644
--- a/src/review/review-diff.ts
+++ b/src/review/review-diff.ts
@@ -35,6 +35,19 @@ export function addedLineCount(patch: string | undefined): number {
   return n;
 }
 
+/** Sum added-line counts across a PR file list — used by auto-review size-cap eligibility (#2065). */
+export function totalAddedLineCount(
+  files: readonly { patch?: string | null | undefined; payload?: { patch?: unknown } | null | undefined }[],
+): number {
+  let total = 0;
+  for (const file of files) {
+    const patch =
+      file.patch ?? (typeof file.payload?.patch === "string" ? file.payload.patch : undefined);
+    total += addedLineCount(patch);
+  }
+  return total;
+}
+
 /** Split a unified patch into hunks (each starting at an `@@` header); any preamble stays as hunk 0. */
 function splitHunks(patch: string): string[] {
   const hunks: string[] = [];
diff --git a/src/signals/focus-manifest.ts b/src/signals/focus-manifest.ts
index 57e0b444b0..0b4b757832 100644
--- a/src/signals/focus-manifest.ts
+++ b/src/signals/focus-manifest.ts
@@ -420,6 +420,10 @@ export type AutoReviewConfig = {
   /** `review.auto_review.skip_docs_only`: when true, PRs whose every changed file classifies as docs skip AI review.
    *  null (default) ⇒ docs PRs reviewed as today. Empty changed-file list ⇒ NOT docs-only (fail-safe eligible). (#2063) */
   skipDocsOnly: boolean | null;
+  /** `review.auto_review.max_added_lines`: skip AI review when total added lines exceed this cap. 0 (default) ⇒ no cap. (#2065) */
+  maxAddedLines: number;
+  /** `review.auto_review.max_files`: skip AI review when changed-file count exceeds this cap. 0 (default) ⇒ no cap. (#2065) */
+  maxFiles: number;
   /** `review.auto_review.base_branches`: base-ref globs whose PRs ARE reviewed; empty/unset ⇒ every base. (#2041) */
   baseBranches: string[];
   /** `review.auto_review.auto_pause_after_reviewed_commits`: after N published AI reviews on this PR, pause further
@@ -433,6 +437,8 @@ export const EMPTY_AUTO_REVIEW_CONFIG: AutoReviewConfig = {
   ignoreTitleKeywords: [],
   skipLabels: [],
   skipDocsOnly: null,
+  maxAddedLines: 0,
+  maxFiles: 0,
   baseBranches: [],
   autoPauseAfterReviewedCommits: null,
 };
@@ -804,6 +810,16 @@ function normalizeOptionalNonNegativeInt(value: JsonValue | undefined, field: st
   return value;
 }
 
+/** Parse auto-review size caps where 0 means disabled (byte-identical default). (#2065) */
+function normalizeAutoReviewSizeCap(value: JsonValue | undefined, field: string, warnings: string[]): number {
+  if (value === undefined || value === null) return 0;
+  if (typeof value !== "number" || !Number.isFinite(value) || !Number.isInteger(value) || value < 0) {
+    warnings.push(`Manifest field "${field}" must be a non-negative integer; ignoring it.`);
+    return 0;
+  }
+  return value;
+}
+
 /** Normalize an optional confidence threshold in [0,1] (#7) — a fractional value (NOT a 0-100 score), so it is
  *  clamped into range WITHOUT rounding. Absent/null ⇒ null (the resolver leaves the gate's 0.93 default in place);
  *  a non-finite/non-number value is ignored with a warning. */
@@ -1778,6 +1794,8 @@ function autoReviewPresent(config: AutoReviewConfig): boolean {
     config.ignoreTitleKeywords.length > 0 ||
     config.skipLabels.length > 0 ||
     config.skipDocsOnly !== null ||
+    config.maxAddedLines > 0 ||
+    config.maxFiles > 0 ||
     config.baseBranches.length > 0 ||
     config.autoPauseAfterReviewedCommits !== null
   );
@@ -1797,6 +1815,8 @@ function parseAutoReviewConfig(value: JsonValue | undefined, warnings: string[])
     ignoreTitleKeywords: parseAutoReviewTitleKeywords(record.ignore_title_keywords, warnings),
     skipLabels: parseAutoReviewSkipLabels(record.skip_labels, warnings),
     skipDocsOnly: normalizeOptionalBoolean(record.skip_docs_only, "review.auto_review.skip_docs_only", warnings),
+    maxAddedLines: normalizeAutoReviewSizeCap(record.max_added_lines, "review.auto_review.max_added_lines", warnings),
+    maxFiles: normalizeAutoReviewSizeCap(record.max_files, "review.auto_review.max_files", warnings),
     baseBranches: parseManifestGlobList(record.base_branches, "review.auto_review.base_branches", warnings),
     autoPauseAfterReviewedCommits: normalizeOptionalNonNegativeInt(
       record.auto_pause_after_reviewed_commits,
@@ -2164,6 +2184,8 @@ export function reviewConfigToJson(review: FocusManifestReviewConfig): JsonValue
     if (review.autoReview.ignoreTitleKeywords.length > 0) autoReview.ignore_title_keywords = [...review.autoReview.ignoreTitleKeywords];
     if (review.autoReview.skipLabels.length > 0) autoReview.skip_labels = [...review.autoReview.skipLabels];
     if (review.autoReview.skipDocsOnly !== null) autoReview.skip_docs_only = review.autoReview.skipDocsOnly;
+    if (review.autoReview.maxAddedLines > 0) autoReview.max_added_lines = review.autoReview.maxAddedLines;
+    if (review.autoReview.maxFiles > 0) autoReview.max_files = review.autoReview.maxFiles;
     if (review.autoReview.baseBranches.length > 0) autoReview.base_branches = [...review.autoReview.baseBranches];
     if (review.autoReview.autoPauseAfterReviewedCommits !== null) {
       autoReview.auto_pause_after_reviewed_commits = review.autoReview.autoPauseAfterReviewedCommits;
@@ -2240,6 +2262,8 @@ export type AutoReviewEligibilityInput = {
   title: string;
   labels: readonly string[];
   changedPaths: readonly string[];
+  addedLineCount: number;
+  changedFileCount: number;
   baseRef: string | null;
   reviewedCommitCount: number;
 };
@@ -2270,6 +2294,12 @@ export function evaluateAutoReviewSkipReason(config: AutoReviewConfig, input: Au
       return "review skipped (docs only)";
     }
   }
+  if (config.maxAddedLines > 0 && input.addedLineCount > config.maxAddedLines) {
+    return "review skipped (too large)";
+  }
+  if (config.maxFiles > 0 && input.changedFileCount > config.maxFiles) {
+    return "review skipped (too large)";
+  }
   if (config.baseBranches.length > 0) {
     const baseRef = input.baseRef?.trim() ?? "";
     if (!baseRef || !config.baseBranches.some((glob) => matchesManifestPath(baseRef, glob))) {
@@ -2292,6 +2322,8 @@ export function resolvePullRequestAutoReviewSkipReason(args: {
   title: string;
   labels?: readonly string[] | undefined;
   changedPaths?: readonly string[] | undefined;
+  addedLineCount?: number | undefined;
+  changedFileCount?: number | undefined;
   baseRef: string | null;
   reviewedCommitCount?: number | undefined;
 }): string | null {
@@ -2302,6 +2334,8 @@ export function resolvePullRequestAutoReviewSkipReason(args: {
     title: args.title,
     labels: args.labels ?? [],
     changedPaths: args.changedPaths ?? [],
+    addedLineCount: args.addedLineCount ?? 0,
+    changedFileCount: args.changedFileCount ?? 0,
     baseRef: args.baseRef,
     reviewedCommitCount: args.reviewedCommitCount ?? 0,
   });
diff --git a/test/unit/auto-review-config-matrix.test.ts b/test/unit/auto-review-config-matrix.test.ts
index 54faa72f43..5166491c88 100644
--- a/test/unit/auto-review-config-matrix.test.ts
+++ b/test/unit/auto-review-config-matrix.test.ts
@@ -24,6 +24,8 @@ describe("review.auto_review parse ↔ reviewConfigToJson round-trip (#2071)", (
     { name: "ignore_title_keywords", autoReview: { ignore_title_keywords: ["WIP", "draft"] } },
     { name: "skip_docs_only: true", autoReview: { skip_docs_only: true } },
     { name: "skip_docs_only: false", autoReview: { skip_docs_only: false } },
+    { name: "max_added_lines", autoReview: { max_added_lines: 500 } },
+    { name: "max_files", autoReview: { max_files: 25 } },
     { name: "base_branches", autoReview: { base_branches: ["main", "release/**"] } },
     { name: "auto_pause_after_reviewed_commits", autoReview: { auto_pause_after_reviewed_commits: 3 } },
     {
@@ -82,6 +84,8 @@ describe("evaluateAutoReviewSkipReason predicate precedence (#2071)", () => {
     title: "WIP: bump deps",
     labels: [],
     changedPaths: [],
+    addedLineCount: 0,
+    changedFileCount: 0,
     baseRef: "develop",
     reviewedCommitCount: 5,
   };
@@ -125,6 +129,12 @@ describe("evaluateAutoReviewSkipReason predicate precedence (#2071)", () => {
       input: { ...allTriggers, isDraft: false, author: "alice", title: "docs: readme", changedPaths: ["README.md"] },
       reason: "review skipped (docs only)",
     },
+    {
+      name: "too large when added-line cap exceeded and earlier filters are off",
+      config: { ...allConfigured, skipDrafts: false, ignoreAuthors: [], ignoreTitleKeywords: [], skipDocsOnly: false, maxAddedLines: 10 },
+      input: { ...allTriggers, isDraft: false, author: "alice", title: "feat", baseRef: "main", addedLineCount: 11 },
+      reason: "review skipped (too large)",
+    },
     {
       name: "base branch when earlier filters are off",
       config: { ...allConfigured, skipDrafts: false, ignoreAuthors: [], ignoreTitleKeywords: [] },
@@ -149,6 +159,8 @@ describe("evaluateAutoReviewSkipReason predicate precedence (#2071)", () => {
         title: "feat: add widget",
         labels: [],
         changedPaths: [],
+        addedLineCount: 0,
+        changedFileCount: 0,
         baseRef: "main",
         reviewedCommitCount: 0,
       },
diff --git a/test/unit/auto-review-wiring.test.ts b/test/unit/auto-review-wiring.test.ts
index 39c16736bd..621e06cde1 100644
--- a/test/unit/auto-review-wiring.test.ts
+++ b/test/unit/auto-review-wiring.test.ts
@@ -100,6 +100,65 @@ describe("review.auto_review wiring (#1954)", () => {
     ).toBeNull();
   });
 
+  it("resolvePullRequestAutoReviewSkipReason: skips oversized PRs when size caps are configured", () => {
+    const linesManifest = parseFocusManifest({ review: { auto_review: { max_added_lines: 10 } } });
+    expect(
+      resolvePullRequestAutoReviewSkipReason({
+        manifest: linesManifest,
+        isDraft: false,
+        author: "alice",
+        title: "feat: big change",
+        addedLineCount: 11,
+        changedFileCount: 1,
+        baseRef: "main",
+      }),
+    ).toBe("review skipped (too large)");
+    expect(
+      resolvePullRequestAutoReviewSkipReason({
+        manifest: linesManifest,
+        isDraft: false,
+        author: "alice",
+        title: "feat: big change",
+        addedLineCount: 10,
+        changedFileCount: 1,
+        baseRef: "main",
+      }),
+    ).toBeNull();
+
+    const filesManifest = parseFocusManifest({ review: { auto_review: { max_files: 2 } } });
+    expect(
+      resolvePullRequestAutoReviewSkipReason({
+        manifest: filesManifest,
+        isDraft: false,
+        author: "alice",
+        title: "feat: wide change",
+        addedLineCount: 1,
+        changedFileCount: 3,
+        baseRef: "main",
+      }),
+    ).toBe("review skipped (too large)");
+    expect(
+      resolvePullRequestAutoReviewSkipReason({
+        manifest: filesManifest,
+        isDraft: false,
+        author: "alice",
+        title: "feat: wide change",
+        addedLineCount: 1,
+        changedFileCount: 2,
+        baseRef: "main",
+      }),
+    ).toBeNull();
+    expect(
+      resolvePullRequestAutoReviewSkipReason({
+        manifest: filesManifest,
+        isDraft: false,
+        author: "alice",
+        title: "feat: wide change",
+        baseRef: "main",
+      }),
+    ).toBeNull();
+  });
+
   it("resolvePullRequestAutoReviewSkipReason: matches the documented *[bot] author glob", () => {
     const manifest = parseFocusManifest({ review: { auto_review: { ignore_authors: ["*[bot]"] } } });
     expect(
@@ -221,6 +280,23 @@ describe("review.auto_review wiring (#1954)", () => {
       }),
     ).resolves.toEqual({ skipReason: "review skipped (docs only)", reviewManifest: docsManifest });
 
+    const sizeManifest = parseFocusManifest({ review: { auto_review: { max_added_lines: 1 } } });
+    loadSpy.mockResolvedValueOnce(sizeManifest);
+    await expect(
+      resolveAutoReviewSkipForPullRequest({} as Env, {
+        authorBlacklisted: false,
+        isFrozenForManualReview: false,
+        repoFullName: "acme/widgets",
+        pr: { number: 9, title: "feat", baseRef: "main", isDraft: false, labels: [] },
+        author: "alice",
+        deliveryId: "d9",
+        headSha: "sha9",
+        changedPaths: ["src/a.ts"],
+        addedLineCount: 2,
+        changedFileCount: 1,
+      }),
+    ).resolves.toEqual({ skipReason: "review skipped (too large)", reviewManifest: sizeManifest });
+
     loadSpy.mockRejectedValueOnce(new Error("manifest unavailable"));
     await expect(
       resolveAutoReviewSkipForPullRequest({} as Env, {
diff --git a/test/unit/focus-manifest.test.ts b/test/unit/focus-manifest.test.ts
index 928daadc46..7aab87f9e4 100644
--- a/test/unit/focus-manifest.test.ts
+++ b/test/unit/focus-manifest.test.ts
@@ -3091,6 +3091,8 @@ describe("review.auto_review (#1954 / #2038–#2041)", () => {
       ignoreTitleKeywords: ["WIP", "draft"],
       skipLabels: ["do-not-review", "wip"],
       skipDocsOnly: null,
+      maxAddedLines: 0,
+      maxFiles: 0,
       baseBranches: ["main", "release/**"],
       autoPauseAfterReviewedCommits: null,
     });
@@ -3122,7 +3124,7 @@ describe("review.auto_review (#1954 / #2038–#2041)", () => {
 
   it("evaluateAutoReviewSkipReason: byte-identical when unset; skips with deterministic reasons when configured", () => {
     const empty = { ...EMPTY_AUTO_REVIEW_CONFIG };
-    const input = { isDraft: true, author: "dependabot[bot]", title: "WIP: bump deps", labels: [] as string[], changedPaths: [] as string[], baseRef: "develop", reviewedCommitCount: 0 };
+    const input = { isDraft: true, author: "dependabot[bot]", title: "WIP: bump deps", labels: [] as string[], changedPaths: [] as string[], addedLineCount: 0, changedFileCount: 0, baseRef: "develop", reviewedCommitCount: 0 };
     expect(evaluateAutoReviewSkipReason(empty, input)).toBeNull();
     expect(evaluateAutoReviewSkipReason({ ...empty, skipDrafts: true }, { ...input, isDraft: true })).toBe("review skipped (draft)");
     expect(evaluateAutoReviewSkipReason({ ...empty, skipDrafts: true }, { ...input, isDraft: false })).toBeNull();
@@ -3142,6 +3144,12 @@ describe("review.auto_review (#1954 / #2038–#2041)", () => {
     expect(evaluateAutoReviewSkipReason({ ...empty, skipDocsOnly: true }, { ...input, changedPaths: ["README.md", "src/a.ts"] })).toBeNull();
     expect(evaluateAutoReviewSkipReason({ ...empty, skipDocsOnly: true }, { ...input, changedPaths: [] })).toBeNull();
     expect(evaluateAutoReviewSkipReason({ ...empty, skipDocsOnly: false }, { ...input, changedPaths: ["README.md"] })).toBeNull();
+    expect(evaluateAutoReviewSkipReason({ ...empty, maxAddedLines: 10 }, { ...input, addedLineCount: 11 })).toBe("review skipped (too large)");
+    expect(evaluateAutoReviewSkipReason({ ...empty, maxAddedLines: 10 }, { ...input, addedLineCount: 10 })).toBeNull();
+    expect(evaluateAutoReviewSkipReason({ ...empty, maxAddedLines: 0 }, { ...input, addedLineCount: 999 })).toBeNull();
+    expect(evaluateAutoReviewSkipReason({ ...empty, maxFiles: 3 }, { ...input, changedFileCount: 4 })).toBe("review skipped (too large)");
+    expect(evaluateAutoReviewSkipReason({ ...empty, maxFiles: 3 }, { ...input, changedFileCount: 3 })).toBeNull();
+    expect(evaluateAutoReviewSkipReason({ ...empty, maxFiles: 0 }, { ...input, changedFileCount: 99 })).toBeNull();
     expect(evaluateAutoReviewSkipReason({ ...empty, baseBranches: ["main"] }, { ...input, baseRef: "develop" })).toBe(
       "review skipped (base branch out of scope)",
     );
@@ -3194,10 +3202,27 @@ describe("review.auto_review (#1954 / #2038–#2041)", () => {
     expect(reviewConfigToJson(labelsOnly.review)).toEqual({ auto_review: { skip_labels: ["do-not-review"] } });
     const docsOnly = parseFocusManifest({ review: { auto_review: { skip_docs_only: true } } });
     expect(reviewConfigToJson(docsOnly.review)).toEqual({ auto_review: { skip_docs_only: true } });
+    const linesCap = parseFocusManifest({ review: { auto_review: { max_added_lines: 500 } } });
+    expect(reviewConfigToJson(linesCap.review)).toEqual({ auto_review: { max_added_lines: 500 } });
+    const filesCap = parseFocusManifest({ review: { auto_review: { max_files: 25 } } });
+    expect(reviewConfigToJson(filesCap.review)).toEqual({ auto_review: { max_files: 25 } });
     const basesOnly = parseFocusManifest({ review: { auto_review: { base_branches: ["main"] } } });
     expect(reviewConfigToJson(basesOnly.review)).toEqual({ auto_review: { base_branches: ["main"] } });
   });
 
+  it("warns on invalid max_added_lines and max_files values", () => {
+    const badLines = parseFocusManifest({ review: { auto_review: { max_added_lines: -1 } } });
+    expect(badLines.review.autoReview.maxAddedLines).toBe(0);
+    expect(badLines.warnings.some((w) => /max_added_lines.*non-negative integer/.test(w))).toBe(true);
+    const badFiles = parseFocusManifest({ review: { auto_review: { max_files: "many" } } });
+    expect(badFiles.review.autoReview.maxFiles).toBe(0);
+    expect(badFiles.warnings.some((w) => /max_files.*non-negative integer/.test(w))).toBe(true);
+    const explicitZero = parseFocusManifest({ review: { auto_review: { max_added_lines: 0, max_files: 0 } } });
+    expect(explicitZero.review.autoReview.maxAddedLines).toBe(0);
+    expect(explicitZero.review.autoReview.maxFiles).toBe(0);
+    expect(reviewConfigToJson(explicitZero.review)).toBeNull();
+  });
+
   it("warns on invalid skip_docs_only values and round-trips explicit false", () => {
     const bad = parseFocusManifest({ review: { auto_review: { skip_docs_only: "yes" } } });
     expect(bad.review.autoReview.skipDocsOnly).toBeNull();
diff --git a/test/unit/queue.test.ts b/test/unit/queue.test.ts
index 688ec6740c..43dc6979ba 100644
--- a/test/unit/queue.test.ts
+++ b/test/unit/queue.test.ts
@@ -3339,6 +3339,54 @@ describe("queue processors", () => {
       expect(audit?.detail).toBe("review skipped (docs only)");
     });
 
+    it("skips AI review when review.auto_review.max_added_lines is exceeded (#2065)", async () => {
+      let aiCalls = 0;
+      const env = createTestEnv({
+        GITHUB_APP_PRIVATE_KEY: await generatePrivateKeyPem(),
+        AI: { run: async () => { aiCalls += 1; return { response: JSON.stringify({ assessment: "Looks fine.", blockers: [], nits: [], suggestions: [] }) }; } } as unknown as Ai,
+        AI_SUMMARIES_ENABLED: "true",
+        AI_PUBLIC_COMMENTS_ENABLED: "true",
+        AI_DAILY_NEURON_BUDGET: "100000",
+      });
+      await seedRegateChurnRepo(env);
+      await upsertRepoFocusManifest(env, "JSONbored/gittensory", { review: { auto_review: { max_added_lines: 1 } } });
+      await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", {
+        number: 80,
+        title: "feat: large change",
+        state: "open",
+        draft: false,
+        user: { login: "contributor" },
+        head: { sha: "a80" },
+        labels: [],
+        body: "Closes #1",
+      } as never);
+      await upsertPullRequestDetailSyncState(env, { repoFullName: "JSONbored/gittensory", pullNumber: 80, status: "complete", reviewsSyncedAt: new Date().toISOString() });
+      vi.stubGlobal("fetch", async (input: RequestInfo | URL, init?: RequestInit) => {
+        const url = input.toString();
+        const method = init?.method ?? "GET";
+        if (url.includes("/access_tokens")) return Response.json({ token: "fake-installation-token" });
+        if (url.includes("/pulls/80/files")) return Response.json([
+          { filename: "src/a.ts", status: "modified", additions: 2, deletions: 0, changes: 2, patch: "@@\n+a\n+b" },
+        ]);
+        if (url.endsWith("/pulls/80")) return Response.json({ number: 80, title: "feat: large change", state: "open", draft: false, user: { login: "contributor" }, head: { sha: "a80" }, labels: [], body: "Closes #1", mergeable_state: "clean" });
+        if (url.includes("/commits/a80/check-runs")) return Response.json({ total_count: 0, check_runs: [] });
+        if (url.includes("/commits/a80/status")) return Response.json({ state: "success", statuses: [] });
+        if (url.includes("/issues/80/comments")) return method === "POST" ? Response.json({ id: 80 }, { status: 201 }) : Response.json([]);
+        if (url.includes("/issues/1")) return Response.json({ number: 1, title: "Issue", state: "open", labels: [], user: { login: "reporter" } });
+        if (url.includes("/branches/")) return Response.json({ protected: false, protection: { required_status_checks: { contexts: [] } } });
+        return Response.json({});
+      });
+
+      await expect(
+        processJob(env, { type: "agent-regate-pr", deliveryId: "auto-review-skip-too-large", repoFullName: "JSONbored/gittensory", prNumber: 80, installationId: 123 }),
+      ).resolves.toBeUndefined();
+      expect(aiCalls).toBe(0);
+      const audit = await env.DB.prepare("select detail from audit_events where event_type = ? and target_key = ?")
+        .bind("github_app.ai_review_auto_review_skipped", "JSONbored/gittensory#80")
+        .first<{ detail: string }>();
+      expect(audit?.detail).toBe("review skipped (too large)");
+    });
+
     it("runs AI review with cached manifest when auto_review eligibility passes (#1954)", async () => {
       let aiCalls = 0;
       const env = createTestEnv({
diff --git a/test/unit/review-diff.test.ts b/test/unit/review-diff.test.ts
index 31b35b8746..7acd142b49 100644
--- a/test/unit/review-diff.test.ts
+++ b/test/unit/review-diff.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { addedLineCount, buildUnifiedReviewDiff, diffFilePriority, keepHighSignalHunks } from "../../src/review/review-diff";
+import { addedLineCount, buildUnifiedReviewDiff, diffFilePriority, keepHighSignalHunks, totalAddedLineCount } from "../../src/review/review-diff";
 
 describe("diffFilePriority — source survives, noise drops first", () => {
   it("ranks source(0) < tests(1) < docs(2) < lockfiles/generated(4)", () => {
@@ -57,6 +57,20 @@ describe("addedLineCount — counts +lines, ignores +++ header", () => {
   });
 });
 
+describe("totalAddedLineCount — sums added lines across PR files (#2065)", () => {
+  it("aggregates patch counts and treats missing patches as zero", () => {
+    expect(totalAddedLineCount([
+      { patch: "@@\n+a\n+b" },
+      { patch: "@@\n+c" },
+      { patch: null },
+      { payload: { patch: "@@\n+d" } },
+      { payload: {} },
+      {},
+    ])).toBe(4);
+    expect(totalAddedLineCount([])).toBe(0);
+  });
+});
+
 describe("buildUnifiedReviewDiff — the #1528 fix: never silently drop the file defining a symbol", () => {
   it("orders SOURCE before a lockfile, so under a tight budget source survives and the lockfile drops", () => {
     const bigLock = `@@\n${"+x\n".repeat(400)}`; // large, low-priority
diff --git a/test/unit/signals-coverage.test.ts b/test/unit/signals-coverage.test.ts
index b3efb40960..7d7eaa879c 100644
--- a/test/unit/signals-coverage.test.ts
+++ b/test/unit/signals-coverage.test.ts
@@ -1127,7 +1127,7 @@ describe("signal coverage edge cases", () => {
       collisions: buildCollisionReport(directRepo.fullName, [], [currentPr]),
       preflight: buildPreflightResult({ repoFullName: directRepo.fullName, title: "Fix isolated issue", body: "Fixes #99", linkedIssues: [99] }, directRepo, [], [currentPr]),
       settings: gateSettings,
-      review: { present: true, footerText: "Reviewed by the Acme maintainer bot.", note: "Run npm test before pushing.", fields: { relatedWork: false }, enrichmentAnalyzers: {}, profile: null, tone: null, securityFocus: null, inlineComments: null, suggestions: null, changedFilesSummary: null, effortScore: null, findingCategories: null, pathInstructions: [], instructions: null, excludePaths: [], pathFilters: [], preMergeChecks: [], autoReview: { skipDrafts: null, ignoreAuthors: [], ignoreTitleKeywords: [], skipLabels: [], skipDocsOnly: null, baseBranches: [], autoPauseAfterReviewedCommits: null }, labelingRules: [], aiModel: { claudeModel: null, claudeEffort: null, codexModel: null, codexEffort: null }, visual: { preview: { urlTemplate: null }, routes: { paths: [], maxRoutes: null }, themes: [] }, linkedIssueSatisfaction: null },
+      review: { present: true, footerText: "Reviewed by the Acme maintainer bot.", note: "Run npm test before pushing.", fields: { relatedWork: false }, enrichmentAnalyzers: {}, profile: null, tone: null, securityFocus: null, inlineComments: null, suggestions: null, changedFilesSummary: null, effortScore: null, findingCategories: null, pathInstructions: [], instructions: null, excludePaths: [], pathFilters: [], preMergeChecks: [], autoReview: { skipDrafts: null, ignoreAuthors: [], ignoreTitleKeywords: [], skipLabels: [], skipDocsOnly: null, maxAddedLines: 0, maxFiles: 0, baseBranches: [], autoPauseAfterReviewedCommits: null }, labelingRules: [], aiModel: { claudeModel: null, claudeEffort: null, codexModel: null, codexEffort: null }, visual: { preview: { urlTemplate: null }, routes: { paths: [], maxRoutes: null }, themes: [] }, linkedIssueSatisfaction: null },
       aiReview: { notes: "The change is focused.\n\n**Nits (2)**\n- Add a test for the </details> edge case.\n- Keep the validator helper scoped." },
     });
     expect(customizedComment).toContain("Reviewed by the Acme maintainer bot."); // custom footer lead