diff --git a/CHANGELOG.md b/CHANGELOG.md
index c95be258..45474c92 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ Full release notes with details on each version: [GitHub Releases](https://githu
 - Feat: `graphify extract --global --as <tag>` flag -- after building a project graph, auto-registers it into the global graph in one step (#729)
 - Feat: `merge-graphs` now prefix-relabels each input graph before composing, preventing silent node ID collisions when two projects share entity names (#729)
 - Fix: `deduplicate_entities` raises `ValueError` if called with nodes spanning multiple repos (cross-project dedup disabled by design -- per-project graphs are deduplicated in isolation) (#729)
+- Fix: `detect_incremental()` now accepts and forwards `follow_symlinks` to `detect()`. Without this, `--update` runs silently miss any files reached through a symlinked sub-tree (e.g. `state_of_truth/` symlinking to a directory outside the corpus root), even when the original full run had detected them. Previously the flag was on `detect()` and `collect_files()` only. (#736)
 
 ## 0.7.6 (2026-05-05)
 
diff --git a/graphify/detect.py b/graphify/detect.py
index 50f9e2c5..4b879636 100644
--- a/graphify/detect.py
+++ b/graphify/detect.py
@@ -771,7 +771,12 @@ def save_manifest(files: dict[str, list[str]], manifest_path: str = _MANIFEST_PA
     Path(manifest_path).write_text(json.dumps(manifest, indent=2), encoding="utf-8")
 
 
-def detect_incremental(root: Path, manifest_path: str = _MANIFEST_PATH) -> dict:
+def detect_incremental(
+    root: Path,
+    manifest_path: str = _MANIFEST_PATH,
+    *,
+    follow_symlinks: bool = False,
+) -> dict:
     """Like detect(), but returns only new or modified files since the last run.
 
     Fast path: mtime unchanged → unchanged (free, no hash).
@@ -779,8 +784,13 @@ def detect_incremental(root: Path, manifest_path: str = _MANIFEST_PATH) -> dict:
     treat as unchanged. Different hash = actually changed, re-extract.
 
     Backwards compatible with legacy manifests storing plain float mtime values.
+
+    The ``follow_symlinks`` flag is forwarded to :func:`detect` so corpora that
+    rely on symlinked sub-trees (e.g. a ``state_of_truth/`` symlink pointing to a
+    directory outside the scan root) are scanned consistently between full and
+    incremental runs.
     """
-    full = detect(root)
+    full = detect(root, follow_symlinks=follow_symlinks)
     manifest = load_manifest(manifest_path)
 
     if not manifest:
diff --git a/tests/test_detect.py b/tests/test_detect.py
index 6ded2fd0..000de351 100644
--- a/tests/test_detect.py
+++ b/tests/test_detect.py
@@ -1,5 +1,5 @@
 from pathlib import Path
-from graphify.detect import classify_file, count_words, detect, FileType, _looks_like_paper, _is_ignored, _load_graphifyignore
+from graphify.detect import classify_file, count_words, detect, detect_incremental, save_manifest, FileType, _looks_like_paper, _is_ignored, _load_graphifyignore
 
 FIXTURES = Path(__file__).parent / "fixtures"
 
@@ -220,6 +220,33 @@ def test_detect_handles_circular_symlinks(tmp_path):
     assert any("main.py" in f for f in result["files"]["code"])
 
 
+def test_detect_incremental_propagates_follow_symlinks(tmp_path, monkeypatch):
+    """detect_incremental must forward follow_symlinks so symlinked sub-trees
+    appear in incremental scans the same way they appear in full scans."""
+    monkeypatch.chdir(tmp_path)
+
+    real_dir = tmp_path / "real_corpus"
+    real_dir.mkdir()
+    (real_dir / "note.md").write_text("# real note\n\nsome content")
+    (tmp_path / "linked_corpus").symlink_to(real_dir)
+
+    manifest_path = str(tmp_path / "manifest.json")
+
+    # Without following symlinks, the symlinked dir contents are invisible.
+    no_link = detect_incremental(tmp_path, manifest_path, follow_symlinks=False)
+    assert not any("linked_corpus" in f for f in no_link["files"]["document"])
+
+    # With follow_symlinks=True, the symlinked dir contents appear and are new.
+    yes_link = detect_incremental(tmp_path, manifest_path, follow_symlinks=True)
+    assert any("linked_corpus" in f for f in yes_link["files"]["document"])
+    assert yes_link["new_total"] >= 2  # real + linked
+
+    # After saving manifest, a second incremental scan should see no changes.
+    save_manifest(yes_link["files"], manifest_path)
+    second = detect_incremental(tmp_path, manifest_path, follow_symlinks=True)
+    assert second["new_total"] == 0
+
+
 def test_classify_video_extensions():
     """Video and audio file extensions should classify as VIDEO."""
     from graphify.detect import FileType