diff --git a/crates/engine/src/doc_list_paths_tests.rs b/crates/engine/src/doc_list_paths_tests.rs
index f69941919..0d73d0736 100644
--- a/crates/engine/src/doc_list_paths_tests.rs
+++ b/crates/engine/src/doc_list_paths_tests.rs
@@ -63,3 +63,20 @@ fn a_plugin_gets_library_names_but_not_their_links() {
     assert!(out.contains("Kit"), "{out}");
     assert!(!out.contains("per-file-secret") && !out.contains("\\\"path\\\""), "{out}");
 }
+
+#[test]
+fn a_plugin_gets_a_fixed_message_for_library_update_failures() {
+    const LINK: &str = "/home/someone/private/kits/kit.figcraft";
+    let mut s = Session::new();
+    s.doc_mut().unwrap().libraries_mut().enabled.push(figcraft_doc::LibraryLink {
+        id: "lib".into(),
+        name: "Kit".into(),
+        path: LINK.into(),
+        version: 3,
+    });
+    let tail = "(call $set_output (i32.const 40000) (call $reply_read (i32.const 40000) (i32.const 20000))) (return (i32.const 0))";
+    install(&mut s, manifest("org.test.upd", "read", &[]), &script(&[("library.updates", json!({}))], OnRefusal::Fail, tail));
+    let out = ex(&mut s, "plugin.run", json!({"id": "org.test.upd"}))["output"].to_string();
+    assert!(out.contains("could not be read"), "{out}");
+    assert!(!out.contains("someone") && !out.contains("private"), "{out}");
+}
diff --git a/crates/engine/src/extensions/plugins.rs b/crates/engine/src/extensions/plugins.rs
index 78044ee71..7677a9b7d 100644
--- a/crates/engine/src/extensions/plugins.rs
+++ b/crates/engine/src/extensions/plugins.rs
@@ -264,16 +264,20 @@ impl figcraft_plugin::Host for EngineHost<'_> {
         r.map(|mut v| {
             // A plugin gets the open files' and libraries' names, not where they are on disk or
             // the share links (with their tokens) that reach them (#1117).
-            if matches!(command, "doc.list" | "library.list") {
-                // `doc.list` is a list; `library.list` keeps its list under `libraries`.
-                let list = if command == "library.list" { v.get_mut("libraries") } else { Some(&mut v) };
+            if matches!(command, "doc.list" | "library.list" | "library.updates") {
+                // `doc.list` is a list; `library.list` keeps its list under `libraries`, and
+                // `library.updates` its failures under `errors`.
+                let list = match command {
+                    "library.list" => v.get_mut("libraries"),
+                    "library.updates" => v.get_mut("errors"),
+                    _ => Some(&mut v),
+                };
                 for e in list.and_then(Value::as_array_mut).into_iter().flatten().filter_map(Value::as_object_mut) {
-                    // An error may quote the path too.
-                    if let Some(Value::String(path)) = e.remove("path")
-                        && !path.is_empty()
-                        && let Some(Value::String(err)) = e.get_mut("error")
-                    {
-                        *err = err.replace(&path, "the library");
+                    e.remove("path");
+                    // A failure's text may quote the path, a token or another form of it: the
+                    // plugin gets a fixed message.
+                    if let Some(err) = e.get_mut("error").filter(|v| v.is_string()) {
+                        *err = json!("the library could not be read");
                     }
                 }
             }