diff --git a/crates/engine/src/cmd/browse.rs b/crates/engine/src/cmd/browse.rs
index e5074d9ed..6406db479 100644
--- a/crates/engine/src/cmd/browse.rs
+++ b/crates/engine/src/cmd/browse.rs
@@ -286,7 +286,7 @@ pub(crate) fn move_folder(s: &mut Session, from: &str, to: &str) -> std::result:
         return Err("the library's own folders can't be moved here".into());
     }
     rename_folder_on_disk(from, to)?;
-    let ops: Vec<Op> = s
+    let mut ops: Vec<Op> = s
         .catalog
         .photos()
         .filter_map(|p| match &p.source {
@@ -301,6 +301,8 @@ pub(crate) fn move_folder(s: &mut Session, from: &str, to: &str) -> std::result:
         })
         .collect();
     let n = ops.len();
+    // what the library knows about the folder (and those inside it) goes along, in the same step
+    ops.extend(s.catalog.folder_records_follow(from, to));
     let name = Path::new(to).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default();
     let renamed = src.parent() == dst.parent();
     let label = if renamed { format!("Rename Folder to “{name}”") } else { format!("Move Folder “{name}”") };
diff --git a/crates/engine/src/cmd/library.rs b/crates/engine/src/cmd/library.rs
index 09d19f0dd..0ae6d4ba0 100644
--- a/crates/engine/src/cmd/library.rs
+++ b/crates/engine/src/cmd/library.rs
@@ -339,7 +339,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Library Folders",
             [],
             None,
-            "{} → [{name, path, count, own, volume, selectable, children}] the disks and the folders the library's photos were imported from, with photo counts (subfolders included in `count`); show one with library.source {kind: libraryFolder, path} (rows with selectable false only open)",
+            "{} → [{name, path, count, own, volume, selectable, label?, children}] the disks and the folders the library's photos were imported from, with photo counts (subfolders included in `count`); show one with library.source {kind: libraryFolder, path} (rows with selectable false only open)",
             always,
             |s, _| Ok(serde_json::to_value(s.catalog.folder_tree()).unwrap_or_default())
         ),
@@ -387,6 +387,29 @@ pub fn specs() -> Vec<CommandSpec> {
                 Ok(json!({"removed": ids.len()}))
             }
         ),
+        cmd!(
+            "folder.label",
+            "Set Folder Color Label",
+            [],
+            None,
+            "{path, label: red|yellow|green|blue|purple|none} — give a folder of the library (one its photos were imported from, see library.folders) a colour label, or take it off; one undo step. The label follows the folder when it is renamed or moved with folder.rename / folder.move → {path, label}",
+            always,
+            |s, p| {
+                const C: &str = "folder.label";
+                let path = str_param(p, "path").filter(|d| !d.trim().is_empty()).ok_or_else(|| bad(C, "missing `path`"))?;
+                let label = match str_param(p, "label").ok_or_else(|| bad(C, "missing `label` (red|yellow|green|blue|purple|none)"))? {
+                    "none" => None,
+                    x => Some(ColorLabel::parse(x).ok_or_else(|| bad(C, format!("unknown label {x:?}")))?),
+                };
+                let f = Filter { library_folder: Some(path.to_string()), ..Default::default() };
+                if s.catalog.query(&f, &Sort::default()).is_empty() {
+                    return Err(bad(C, format!("{path}: no photo in the library was imported from it")));
+                }
+                let op = s.catalog.folder_label_op(path, label);
+                s.commit(if label.is_some() { "Set Folder Color Label" } else { "Remove Folder Color Label" }, op)?;
+                Ok(json!({"path": path, "label": label}))
+            }
+        ),
         cmd!("library.clearFilter", "Clear Filters", ["View"], None, "{}", always, |s, _| {
             s.filter = Default::default();
             Ok(json!({"count": s.visible().len()}))
diff --git a/crates/engine/src/tests_folders.rs b/crates/engine/src/tests_folders.rs
index a94921373..2e60ce1ad 100644
--- a/crates/engine/src/tests_folders.rs
+++ b/crates/engine/src/tests_folders.rs
@@ -8,6 +8,11 @@
 //! * Removing a folder from the library moves its photos to Recently Deleted (one undo step) and
 //!   leaves every file where it is.
 //! * Renaming or moving a folder on disk keeps the chosen folder chosen.
+//! * Given a folder of the library, an agent gives it a colour label with `folder.label`; the
+//!   folder list shows it, undo takes it back, and only folders the library holds photos in can
+//!   be labelled.
+//! * A labelled folder keeps its label when it is renamed or moved on disk, and so do the folders
+//!   inside it; undo puts the labels back where they were.
 
 use lightcraft_catalog::{Op, Photo, Source};
 use serde_json::json;
@@ -463,3 +468,84 @@ fn a_blank_folder_filter_is_no_filter() {
     s.execute("library.filter", &json!({"libraryFolder": "  "})).unwrap();
     assert_eq!(s.filter, lightcraft_catalog::Filter::default(), "no hidden 'filters active' state");
 }
+
+/// The label `library.folders` reports for the row at `path`.
+fn listed_label(s: &mut Session, path: &str) -> Option<String> {
+    fn find(rows: &serde_json::Value, key: &str) -> Option<serde_json::Value> {
+        rows.as_array()?.iter().find_map(|r| {
+            if r["path"].as_str().map(lightcraft_catalog::query::folder_key).as_deref() == Some(key) {
+                Some(r.clone())
+            } else {
+                find(&r["children"], key)
+            }
+        })
+    }
+    let rows = s.execute("library.folders", &json!({})).unwrap();
+    let row = find(&rows, &lightcraft_catalog::query::folder_key(path)).unwrap_or_else(|| panic!("no row for {path}: {rows}"));
+    row["label"].as_str().map(str::to_string)
+}
+
+#[test]
+fn a_labelled_folder_shows_its_label_in_the_folder_list_until_undone() {
+    let mut s = session();
+    s.execute("folder.label", &json!({"path": "/pics/trip", "label": "green"})).unwrap();
+    assert_eq!(listed_label(&mut s, "/pics/trip").as_deref(), Some("green"));
+    assert_eq!(listed_label(&mut s, "/pics/home"), None, "its neighbour has none");
+    s.execute("folder.label", &json!({"path": "/pics/trip", "label": "none"})).unwrap();
+    assert_eq!(listed_label(&mut s, "/pics/trip"), None);
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(listed_label(&mut s, "/pics/trip").as_deref(), Some("green"), "undo puts the label back");
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(listed_label(&mut s, "/pics/trip"), None);
+}
+
+#[test]
+fn only_a_folder_of_the_library_takes_a_known_label() {
+    let mut s = session();
+    let before = s.catalog.to_snapshot();
+    for (p, why) in [
+        (json!({"path": "/pics/trip", "label": "mauve"}), "unknown label"),
+        (json!({"path": "/pics/trip"}), "missing label"),
+        (json!({"label": "red"}), "missing path"),
+        (json!({"path": "  ", "label": "red"}), "blank path"),
+        (json!({"path": "/elsewhere", "label": "red"}), "no photo was imported from it"),
+        (json!({"path": "pics/trip", "label": "red"}), "a relative path"),
+    ] {
+        assert!(s.execute("folder.label", &p).is_err(), "{why}");
+    }
+    assert_eq!(s.catalog.to_snapshot(), before, "nothing changed");
+}
+
+#[test]
+fn labels_follow_a_renamed_folder_and_undo_puts_them_back() {
+    let dir = Scratch::new("label-rename");
+    std::fs::create_dir_all(dir.0.join("trip/day1")).unwrap();
+    let (trip, day1) = (dir.path("trip"), dir.path("trip/day1"));
+    let mut s = Session::new();
+    add(&mut s, &format!("{trip}/a.jpg"));
+    add(&mut s, &format!("{day1}/b.jpg"));
+    s.execute("folder.label", &json!({"path": trip, "label": "red"})).unwrap();
+    s.execute("folder.label", &json!({"path": day1, "label": "blue"})).unwrap();
+    s.execute("folder.rename", &json!({"path": trip, "name": "holiday"})).unwrap();
+    assert_eq!(listed_label(&mut s, &dir.path("holiday")).as_deref(), Some("red"));
+    assert_eq!(listed_label(&mut s, &dir.path("holiday/day1")).as_deref(), Some("blue"), "the folder inside goes along");
+    assert_eq!(s.catalog.folder_record(&trip), None, "nothing stays behind");
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(listed_label(&mut s, &trip).as_deref(), Some("red"));
+    assert_eq!(listed_label(&mut s, &day1).as_deref(), Some("blue"));
+    s.execute("edit.redo", &json!({})).unwrap();
+    assert_eq!(listed_label(&mut s, &dir.path("holiday")).as_deref(), Some("red"), "redo carries them again");
+}
+
+#[test]
+fn labels_follow_a_moved_folder() {
+    let dir = Scratch::new("label-move");
+    std::fs::create_dir_all(dir.0.join("trip")).unwrap();
+    std::fs::create_dir_all(dir.0.join("archive")).unwrap();
+    let trip = dir.path("trip");
+    let mut s = Session::new();
+    add(&mut s, &format!("{trip}/a.jpg"));
+    s.execute("folder.label", &json!({"path": trip, "label": "yellow"})).unwrap();
+    s.execute("folder.move", &json!({"path": trip, "into": dir.path("archive")})).unwrap();
+    assert_eq!(listed_label(&mut s, &dir.path("archive/trip")).as_deref(), Some("yellow"));
+}