diff --git a/app/main.py b/app/main.py
index d7ff8f4..6046c18 100644
--- a/app/main.py
+++ b/app/main.py
@@ -411,6 +411,7 @@ def decide(group_id: int, body: DecideBody):
         )
         status = "keeper" if is_k else "redundant"
         cur.execute("UPDATE files SET status=? WHERE id=?", (status, fid))
+        sc.log_decision(cur, fid, group_id, status, "manual")
 
     cur.execute("UPDATE duplicate_groups SET reviewed=1 WHERE id=?", (group_id,))
     con.commit()
@@ -425,6 +426,9 @@ def skip_group(group_id: int):
     cur.execute("SELECT id FROM duplicate_groups WHERE id=?", (group_id,))
     if not cur.fetchone():
         raise HTTPException(404, "Group not found")
+    cur.execute("SELECT file_id FROM duplicate_members WHERE group_id=?", (group_id,))
+    for r in cur.fetchall():
+        sc.log_decision(cur, r["file_id"], group_id, "skip", "manual")
     cur.execute("UPDATE duplicate_groups SET reviewed=1 WHERE id=?", (group_id,))
     con.commit()
     con.close()
@@ -445,6 +449,7 @@ def keep_all(group_id: int):
             (group_id, r["file_id"]),
         )
         cur.execute("UPDATE files SET status='keeper' WHERE id=?", (r["file_id"],))
+        sc.log_decision(cur, r["file_id"], group_id, "keeper", "keep-all")
     cur.execute("UPDATE duplicate_groups SET reviewed=1 WHERE id=?", (group_id,))
     con.commit()
     con.close()
@@ -465,6 +470,7 @@ def unreview_group(group_id: int):
             (group_id, r["file_id"]),
         )
         cur.execute("UPDATE files SET status='pending' WHERE id=?", (r["file_id"],))
+        sc.log_decision(cur, r["file_id"], group_id, "unreview", "manual")
     cur.execute("UPDATE duplicate_groups SET reviewed=0 WHERE id=?", (group_id,))
     con.commit()
     con.close()
@@ -504,6 +510,11 @@ def auto_resolve_exact():
                 "UPDATE files SET status=? WHERE id=?",
                 ("keeper" if is_k else "redundant", m["id"]),
             )
+            sc.log_decision(
+                cur, m["id"], gid,
+                "keeper" if is_k else "redundant",
+                "auto-resolve-exact",
+            )
         cur.execute("UPDATE duplicate_groups SET reviewed=1 WHERE id=?", (gid,))
         resolved += 1
 
diff --git a/app/scanner.py b/app/scanner.py
index 3e57798..2ca4841 100644
--- a/app/scanner.py
+++ b/app/scanner.py
@@ -68,6 +68,22 @@ def get_db() -> sqlite3.Connection:
     return con
 
 
+def log_decision(cur, file_id: int, group_id: int | None, action: str, reason: str):
+    """Append a row to the decisions audit log.
+
+    Captures the file's sha256 at decision time so a future move/delete tool
+    can detect when a file has changed since the user reviewed it.
+    """
+    cur.execute("SELECT sha256 FROM files WHERE id=?", (file_id,))
+    row = cur.fetchone()
+    sha = row["sha256"] if row else None
+    cur.execute(
+        "INSERT INTO decisions (file_id, group_id, action, reason, sha256_at_decision) "
+        "VALUES (?, ?, ?, ?, ?)",
+        (file_id, group_id, action, reason, sha),
+    )
+
+
 def init_db():
     con = get_db()
     cur = con.cursor()
@@ -122,12 +138,27 @@ def init_db():
             suggested INTEGER DEFAULT 0
         );
 
-        CREATE INDEX IF NOT EXISTS idx_sha256   ON files(sha256);
-        CREATE INDEX IF NOT EXISTS idx_phash    ON files(phash);
-        CREATE INDEX IF NOT EXISTS idx_exif_dt  ON files(exif_datetime, exif_device);
-        CREATE INDEX IF NOT EXISTS idx_size_dim ON files(file_size, width, height);
-        CREATE INDEX IF NOT EXISTS idx_status   ON files(status);
+        CREATE TABLE IF NOT EXISTS decisions (
+            id                 INTEGER PRIMARY KEY AUTOINCREMENT,
+            file_id            INTEGER NOT NULL,
+            group_id           INTEGER,
+            action             TEXT NOT NULL,
+            reason             TEXT,
+            sha256_at_decision TEXT,
+            decided_at         TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            FOREIGN KEY (file_id)  REFERENCES files(id)            ON DELETE CASCADE,
+            FOREIGN KEY (group_id) REFERENCES duplicate_groups(id) ON DELETE SET NULL
+        );
+
+        CREATE INDEX IF NOT EXISTS idx_sha256          ON files(sha256);
+        CREATE INDEX IF NOT EXISTS idx_phash           ON files(phash);
+        CREATE INDEX IF NOT EXISTS idx_exif_dt         ON files(exif_datetime, exif_device);
+        CREATE INDEX IF NOT EXISTS idx_size_dim        ON files(file_size, width, height);
+        CREATE INDEX IF NOT EXISTS idx_status          ON files(status);
+        CREATE INDEX IF NOT EXISTS idx_decisions_file  ON decisions(file_id);
+        CREATE INDEX IF NOT EXISTS idx_decisions_group ON decisions(group_id);
     """)
+
     # Migration: add new columns to scans if upgrading from older schema
     for col, defn in [
         ("files_indexed", "INTEGER DEFAULT 0"),
@@ -944,6 +975,11 @@ def run_scan(folder_path: str, scan_id: int, mode: str = "incremental"):
                         "UPDATE files SET status=? WHERE id=?",
                         ("keeper" if is_k else "redundant", fid),
                     )
+                    log_decision(
+                        cur, fid, gid,
+                        "keeper" if is_k else "redundant",
+                        "rescan-restore",
+                    )
                 restored += 1
             con.commit()
             scan_state["message"] = f"Restored {restored:,} prior review decisions"