style(e2e_ui): format assert with ruff 0.15.16 to match CI

Co-authored-by: Isaac

ap-web/src/pages/ChatPage.tsx

@@ -3324,7 +3324,7 @@ export function Composer({
         ref={fileInputRef}
         type="file"
         multiple
-        accept="image/*,application/pdf,text/*"
+        accept="image/*,application/pdf,text/*,application/json"
         className="hidden"
         onChange={(e) => {
           if (e.target.files) {

ap-web/src/shell/NewChatDialog.tsx

@@ -1298,7 +1298,7 @@ export function NewChatLandingScreen() {
               ref={fileInputRef}
               type="file"
               multiple
-              accept="image/*,application/pdf,text/*"
+              accept="image/*,application/pdf,text/*,application/json"
               className="hidden"
               data-testid="new-chat-landing-file-input"
               onChange={(e) => {

tests/e2e_ui/chat/test_composer_attachments.py

@@ -26,12 +26,19 @@ from pathlib import Path
 from playwright.sync_api import Page, expect
 
 _COMPOSER = "Ask the agent anything…"
-# Composer accepts image/*,application/pdf,text/* (the hidden input's accept
-# attr); a .txt file is in-scope and keeps the fixture trivial. ``set_input_files``
-# bypasses the accept filter anyway — ``addFiles`` does no client-side filtering.
+# Composer accepts image/*,application/pdf,text/*,application/json (the hidden
+# input's accept attr); a .txt file is in-scope and keeps the fixture trivial.
+# ``set_input_files`` bypasses the accept filter anyway — ``addFiles`` does no
+# client-side filtering.
 _ATTACH_NAME = "attach_sample.txt"
 _ATTACH_BODY = "composer attachment e2e sample\n"
 
+# JSON is its own MIME (``application/json``), which is NOT covered by the
+# ``text/*`` wildcard, so it has to be listed in the ``accept`` attr explicitly
+# for the OS picker (and the drag-drop ``matchesAccept`` validator) to admit it.
+_JSON_NAME = "attach_sample.json"
+_JSON_BODY = '{"composer": "attachment", "e2e": true}\n'
+
 
 def test_attach_then_remove_file(
     page: Page, seeded_session: tuple[str, str], tmp_path: Path
@@ -59,3 +66,38 @@ def test_attach_then_remove_file(
     remove_button.click()
     expect(remove_button).to_be_hidden(timeout=10_000)
     expect(page.get_by_text(_ATTACH_NAME, exact=True)).to_be_hidden()
+
+
+def test_attach_json_file(page: Page, seeded_session: tuple[str, str], tmp_path: Path) -> None:
+    """A ``.json`` file is admitted by the picker and attaches as a chip.
+
+    Guards the change that added ``application/json`` to the composer's
+    ``accept`` list. Two things are asserted:
+
+    1. The hidden input advertises ``application/json`` in its ``accept`` attr.
+       This is the part the OS file picker and the drag-drop ``matchesAccept``
+       validator (``prompt-input.tsx``) actually read — and the part that would
+       regress if the MIME were dropped from the list. ``set_input_files`` can't
+       cover it because it bypasses the accept filter entirely.
+    2. Driving a real ``.json`` file through the input still yields the chip +
+       remove control, i.e. ``addFiles`` accepts the JSON end-to-end.
+    """
+    base_url, session_id = seeded_session
+    sample = tmp_path / _JSON_NAME
+    sample.write_text(_JSON_BODY)
+
+    page.goto(f"{base_url}/c/{session_id}")
+    expect(page.get_by_placeholder(_COMPOSER)).to_be_visible(timeout=30_000)
+
+    file_input = page.locator('input[type="file"][accept*="image/"]')
+    # The accept attr is what gates the picker/drag-drop; assert JSON is listed.
+    accept = file_input.get_attribute("accept")
+    assert accept is not None and "application/json" in accept, (
+        f"composer file input should accept application/json; got {accept!r}"
+    )
+
+    file_input.set_input_files(str(sample))
+
+    remove_button = page.get_by_role("button", name=f"Remove {_JSON_NAME}")
+    expect(remove_button).to_be_visible(timeout=10_000)
+    expect(page.get_by_text(_JSON_NAME, exact=True)).to_be_visible()