diff --git a/src/review/review-grounding.ts b/src/review/review-grounding.ts
index 378efaafec..a9c3922af7 100644
--- a/src/review/review-grounding.ts
+++ b/src/review/review-grounding.ts
@@ -135,8 +135,11 @@ export async function fetchFullFileContents(
 ): Promise<ChangedFileContent[] | undefined> {
   if (!flags.fullFileContext || !ref) return undefined;
   // Source-first ordering (the diff's own priority) so the most-relevant files are inlined before the budget runs out.
+  // A newly ADDED file is excluded here (#3897): every line of it is already a `+` line in the diff itself
+  // (sent in the same prompt), so fetching + inlining its full content again is a byte-for-byte duplicate --
+  // wasted GitHub API round-trip and wasted prompt budget that a genuinely modified file needs more.
   const candidates = files
-    .filter((file) => file.status !== "removed" && !SKIP_EXT.test(file.filename))
+    .filter((file) => file.status !== "removed" && file.status !== "added" && !SKIP_EXT.test(file.filename))
     .sort((a, b) => diffFilePriority(a.filename) - diffFilePriority(b.filename));
   const out: ChangedFileContent[] = [];
   let used = 0;
diff --git a/test/unit/review-grounding.test.ts b/test/unit/review-grounding.test.ts
index 14b7ec8d8d..f4159ee337 100644
--- a/test/unit/review-grounding.test.ts
+++ b/test/unit/review-grounding.test.ts
@@ -174,13 +174,17 @@ describe("review-grounding: fetchFullFileContents (injected FileFetcher, fail-sa
         ["assets/icon.heic"],
         ["dist/pkg.tgz"],
         ["old.ts", "removed"],
+        ["src/new.ts", "added"],
       ),
       fetcher,
     );
     expect(out).toBeDefined();
-    // source (priority 0) before docs (priority 2); binary + removed excluded before fetch
+    // source (priority 0) before docs (priority 2); binary + removed + added excluded before fetch
     expect(out?.map((f) => f.path)).toEqual(["src/a.ts", "README.md"]);
     expect(reads).toEqual(["src/a.ts", "README.md"]);
+    // #3897: an ADDED file's entire body is already every `+` line of the diff -- fetching it again
+    // would duplicate that content in the prompt, so it's excluded the same way "removed" is.
+    expect(reads).not.toContain("src/new.ts");
     for (const path of binary) expect(reads).not.toContain(path);
   });