diff --git a/frontend/src/app/plugins/library.cljs b/frontend/src/app/plugins/library.cljs
index b97343ec20..9fb646f205 100644
--- a/frontend/src/app/plugins/library.cljs
+++ b/frontend/src/app/plugins/library.cljs
@@ -1059,6 +1059,9 @@
     :setPluginData
     (fn [key value]
       (cond
+        (not= file-id (:current-file-id @st/state))
+        (u/not-valid plugin-id :setPluginData-non-local-library file-id)
+
         (not (string? key))
         (u/not-valid plugin-id :setPluginData-key key)
 
@@ -1092,6 +1095,9 @@
     :setSharedPluginData
     (fn [namespace key value]
       (cond
+        (not= file-id (:current-file-id @st/state))
+        (u/not-valid plugin-id :setSharedPluginData-non-local-library file-id)
+
         (not (string? namespace))
         (u/not-valid plugin-id :setSharedPluginData-namespace namespace)
 
diff --git a/frontend/src/app/plugins/page.cljs b/frontend/src/app/plugins/page.cljs
index 76bc45a832..e668bc8756 100644
--- a/frontend/src/app/plugins/page.cljs
+++ b/frontend/src/app/plugins/page.cljs
@@ -272,13 +272,13 @@
         (st/emit! (dp/set-plugin-data file-id :page id (keyword "shared" namespace) key value))))
 
     :getSharedPluginDataKeys
-    (fn [self namespace]
+    (fn [namespace]
       (cond
         (not (string? namespace))
         (u/not-valid plugin-id :page-plugin-data-namespace namespace)
 
         :else
-        (let [page (u/proxy->page self)]
+        (let [page (u/locate-page file-id id)]
           (apply array (keys (dm/get-in page [:plugin-data (keyword "shared" namespace)]))))))
 
     :openPage
diff --git a/plugins/CHANGELOG.md b/plugins/CHANGELOG.md
index 00095c38b5..80dee3f1c9 100644
--- a/plugins/CHANGELOG.md
+++ b/plugins/CHANGELOG.md
@@ -52,6 +52,8 @@
 - **plugins-runtime**: `penpot.openPage()` (and `Page.openPage()`) now resolves immediately when the target page is already active, instead of waiting forever for a page-initialization event that never fires.
 - **plugins-runtime**: `Shape.shadows`, `Shape.exports` and grid `rows`/`columns` now return live proxies, so writing a member on a returned shadow/export/track (e.g. `shape.shadows[0].blur = 7`) persists to the shape instead of mutating a detached snapshot that was silently discarded. The shadow `color` remains a plain snapshot (reconfigure it by assigning `shadow.color`).
 - **plugins-runtime**: Setting a variant component's `path` now renames the whole variant (its container and every main instance), like the `name` setter already did, instead of renaming only the component and leaving the file referentially inconsistent (which the backend rejected on save with a `variant-component-bad-name` error).
+- **plugins-runtime**: `Page.getSharedPluginDataKeys(namespace)` now works instead of always raising a namespace validation error: the implementation expected a spurious leading argument, so the caller's `namespace` was read as a missing second argument.
+- **plugins-runtime**: Storing plugin data on a connected (non-local) shared library is now consistently rejected with a `setPluginData-non-local-library` error on the `Library` object as well as its assets (colors, typographies, components). Previously the `Library` object accepted the write and applied it optimistically, but plugin data is not part of library synchronization and the change only persists when the caller can edit the library file — on a read-only shared library it failed silently and was lost on reload. Plugin data can only be stored on the file currently being edited.
 
 ## 1.4.2 (2026-01-21)
 
diff --git a/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts b/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts
index 5f16958282..7d3a8ccf0a 100644
--- a/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts
+++ b/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts
@@ -34,6 +34,24 @@ describe('Library', () => {
     expect(Array.isArray(ctx.penpot.library.connected)).toBe(true);
   });
 
+  // The Library object itself carries plugin data (it extends PluginData),
+  // stored on the underlying file. Exercised on the local library; the
+  // connected-library case (writing to a shared library's file/assets) shares
+  // the same code path but can't be fixtured here (connecting a library hangs).
+  test('local library stores plugin data', (ctx) => {
+    const lib = ctx.penpot.library.local;
+    lib.setPluginData('k', 'v');
+    expect(lib.getPluginData('k')).toBe('v');
+    expect(lib.getPluginDataKeys()).toContain('k');
+  });
+
+  test('local library stores shared plugin data', (ctx) => {
+    const lib = ctx.penpot.library.local;
+    lib.setSharedPluginData('ns', 'k', 'v');
+    expect(lib.getSharedPluginData('ns', 'k')).toBe('v');
+    expect(lib.getSharedPluginDataKeys('ns')).toContain('k');
+  });
+
   test('library elements expose a libraryId', (ctx) => {
     const color = ctx.penpot.library.local.createColor();
     expect(typeof color.libraryId).toBe('string');
@@ -136,6 +154,13 @@ describe('Library', () => {
       expect(color.getPluginData('k')).toBe('v');
       expect(color.getPluginDataKeys()).toContain('k');
     });
+
+    test('color shared plugin data round-trips', (ctx) => {
+      const color = ctx.penpot.library.local.createColor();
+      color.setSharedPluginData('ns', 'k', 'v');
+      expect(color.getSharedPluginData('ns', 'k')).toBe('v');
+      expect(color.getSharedPluginDataKeys('ns')).toContain('k');
+    });
   });
 
   describe('Typographies', () => {
@@ -170,6 +195,13 @@ describe('Library', () => {
       expect(typo.getPluginDataKeys()).toContain('k');
     });
 
+    test('typography shared plugin data round-trips', (ctx) => {
+      const typo = ctx.penpot.library.local.createTypography();
+      typo.setSharedPluginData('ns', 'k', 'v');
+      expect(typo.getSharedPluginData('ns', 'k')).toBe('v');
+      expect(typo.getSharedPluginDataKeys('ns')).toContain('k');
+    });
+
     test('typography fontFamily and fontId round-trip', (ctx) => {
       const typo = ctx.penpot.library.local.createTypography();
       expect(typeof typo.fontFamily).toBe('string');
@@ -256,6 +288,15 @@ describe('Library', () => {
       expect(comp.getPluginDataKeys()).toContain('k');
     });
 
+    test('component shared plugin data round-trips', (ctx) => {
+      const rect = ctx.penpot.createRectangle();
+      ctx.board.appendChild(rect);
+      const comp = ctx.penpot.library.local.createComponent([rect]);
+      comp.setSharedPluginData('ns', 'k', 'v');
+      expect(comp.getSharedPluginData('ns', 'k')).toBe('v');
+      expect(comp.getSharedPluginDataKeys('ns')).toContain('k');
+    });
+
     test('component instance and mainInstance return shapes', (ctx) => {
       const rect = ctx.penpot.createRectangle();
       ctx.board.appendChild(rect);
diff --git a/plugins/apps/plugin-api-test-suite/src/tests/plugin-data.test.ts b/plugins/apps/plugin-api-test-suite/src/tests/plugin-data.test.ts
index 254717e63e..5564b2e3f1 100644
--- a/plugins/apps/plugin-api-test-suite/src/tests/plugin-data.test.ts
+++ b/plugins/apps/plugin-api-test-suite/src/tests/plugin-data.test.ts
@@ -26,6 +26,41 @@ describe('Plugin data', () => {
     if (file) {
       file.setPluginData('fileKey', 'fileValue');
       expect(file.getPluginData('fileKey')).toBe('fileValue');
+      expect(file.getPluginDataKeys()).toContain('fileKey');
+    }
+  });
+
+  test('shared plugin data round-trips on the file', (ctx) => {
+    const file = ctx.penpot.currentFile;
+    expect(file).not.toBeNull();
+    if (file) {
+      file.setSharedPluginData('ns', 'fileShared', 'fileSharedValue');
+      expect(file.getSharedPluginData('ns', 'fileShared')).toBe(
+        'fileSharedValue',
+      );
+      expect(file.getSharedPluginDataKeys('ns')).toContain('fileShared');
+    }
+  });
+
+  test('plugin data round-trips on a page', (ctx) => {
+    const page = ctx.penpot.currentPage;
+    expect(page).not.toBeNull();
+    if (page) {
+      page.setPluginData('pageKey', 'pageValue');
+      expect(page.getPluginData('pageKey')).toBe('pageValue');
+      expect(page.getPluginDataKeys()).toContain('pageKey');
+    }
+  });
+
+  test('shared plugin data round-trips on a page', (ctx) => {
+    const page = ctx.penpot.currentPage;
+    expect(page).not.toBeNull();
+    if (page) {
+      page.setSharedPluginData('ns', 'pageShared', 'pageSharedValue');
+      expect(page.getSharedPluginData('ns', 'pageShared')).toBe(
+        'pageSharedValue',
+      );
+      expect(page.getSharedPluginDataKeys('ns')).toContain('pageShared');
     }
   });
 
@@ -45,6 +80,47 @@ describe('Plugin data', () => {
     expect(rect.getPluginDataKeys()).toContain('');
   });
 
+  // Keys are opaque strings: no case normalization is applied. A camelCase key
+  // and its kebab-case spelling are distinct entries that each round-trip
+  // independently. Pins that behaviour so a future key-normalization regression
+  // (reported as camelCase keys "behaving incorrectly") would be caught here.
+  test('camelCase and kebab-case keys are distinct and both round-trip', (ctx) => {
+    const rect = ctx.penpot.createRectangle();
+    ctx.board.appendChild(rect);
+    rect.setPluginData('myKey', 'camel');
+    rect.setPluginData('my-key', 'kebab');
+    expect(rect.getPluginData('myKey')).toBe('camel');
+    expect(rect.getPluginData('my-key')).toBe('kebab');
+    const keys = rect.getPluginDataKeys();
+    expect(keys).toContain('myKey');
+    expect(keys).toContain('my-key');
+  });
+
+  // Same guarantee at the file-data storage location (a distinct code path from
+  // shape/page objects), covering a camelCase key on the file itself.
+  test('a camelCase key round-trips on the file', (ctx) => {
+    const file = ctx.penpot.currentFile;
+    expect(file).not.toBeNull();
+    if (file) {
+      file.setPluginData('camelCaseFileKey', 'value');
+      expect(file.getPluginData('camelCaseFileKey')).toBe('value');
+      expect(file.getPluginDataKeys()).toContain('camelCaseFileKey');
+    }
+  });
+
+  // camelCase is likewise preserved in the shared namespace and the shared key.
+  test('camelCase shared namespace and key round-trip', (ctx) => {
+    const rect = ctx.penpot.createRectangle();
+    ctx.board.appendChild(rect);
+    rect.setSharedPluginData('myNamespace', 'myKey', 'camel');
+    rect.setSharedPluginData('myNamespace', 'my-key', 'kebab');
+    expect(rect.getSharedPluginData('myNamespace', 'myKey')).toBe('camel');
+    expect(rect.getSharedPluginData('myNamespace', 'my-key')).toBe('kebab');
+    const keys = rect.getSharedPluginDataKeys('myNamespace');
+    expect(keys).toContain('myKey');
+    expect(keys).toContain('my-key');
+  });
+
   test('setPluginData with a non-string value throws', (ctx) => {
     const rect = ctx.penpot.createRectangle();
     ctx.board.appendChild(rect);