Files that outlived the chats that held them, and a page that led with its footnotes

The second audit pass. Four things, and the first two were reported.

The Prompts page put a screen of variables and a screen of preview above
the editor, so the tabs began two screens down and switching one had to
drag the whole page to be any use -- and on a short tab it could not drag
far enough, leaving the panel stranded above a screenful of nothing.
Editor first, reference after, bar sticky. Custom themes were three fixed
slots: fifty-seven empty colour boxes on a fresh instance and no way to
make a fourth theme. One block per theme plus a blank one, colours behind
a disclosure. Both measured rather than argued about -- rendered through
TestClient and driven under headless Chromium, where the tab bar moved
385->642px before and does not move now, and the themes page went from
5495px to 2820px.

Asking where generated images go found the other two. Deleting a chat
cascades to the attachment rows and leaves every file on disk; the helper
written for exactly that was called from one place, and it was not the
delete button, a schedule's chat, a helper's chat or deleting an account.
Underneath it, `claim` bound message_id and never chat_id, so anything
picked before a chat existed kept an empty chat_id forever -- which six
readers filter on, so those files were also unnamed in the prompt,
unopenable in the canvas, and invisible to the one caller the cleanup had.

And folders nest now. The route has handled parent_id since folders
existed, with a cycle guard and a depth cap the move path never applied;
the sidebar has always drawn a tree. Nothing could ask for one.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/lembas/services/chat.py

@@ -621,6 +621,37 @@ async def summarise_for_compaction(
     return raw.strip()
 
 
+def delete_chats(db: DBSession, chats) -> int:
+    """Delete chats, and the files their attachments point at.
+
+    **The one way to delete a chat.** `db.delete(chat)` cascades to its messages
+    and to its attachment *rows*, and leaves every file on disk -- a generated
+    image, an uploaded PDF, a photo -- with nothing that will ever look at them
+    again: `sweep_orphans` only considers uploads that were never attached.
+
+    `files_service.remove_files_for_chats` was written for exactly this and was
+    called from one place, the temporary sweep. The delete button, a schedule's
+    task chat, a helper's hidden chat and deleting an account all went straight
+    to `db.delete`, so four of the five ways a chat can end leaked its files.
+    That is `sharing.forget_principal` again: a helper that exists, is correct,
+    and is not called on the path that needs it.
+
+    The order matters and is why this is a function rather than a note. The
+    files have to be unlinked **while the rows still say which they are**, so it
+    happens before the delete and in the same session.
+
+    Does not commit -- the caller decides, because some of them are deleting
+    other things in the same transaction.
+    """
+    live = [chat for chat in chats if chat is not None]
+    if not live:
+        return 0
+    files_service.remove_files_for_chats(db, [chat.id for chat in live])
+    for chat in live:
+        db.delete(chat)
+    return len(live)
+
+
 def sweep_temporary(db: DBSession, older_than: timedelta = TEMPORARY_LIFETIME) -> int:
     """Delete temporary chats nobody has touched for a day.
 
@@ -652,9 +683,7 @@ def sweep_temporary(db: DBSession, older_than: timedelta = TEMPORARY_LIFETIME) -
     if not stale:
         return 0
 
-    files_service.remove_files_for_chats(db, [chat.id for chat in stale])
-    for chat in stale:
-        db.delete(chat)
+    delete_chats(db, stale)
     db.commit()
     log.info("swept %d temporary chat(s)", len(stale))
     return len(stale)

src/lembas/services/files.py

@@ -29,7 +29,7 @@ from sqlalchemy import select
 from sqlalchemy.orm import Session as DBSession
 
 from lembas.config import settings
-from lembas.db.models import KIND_DOCUMENT, KIND_IMAGE, KIND_TEXT, Attachment
+from lembas.db.models import KIND_DOCUMENT, KIND_IMAGE, KIND_TEXT, Attachment, Message
 
 log = logging.getLogger(__name__)
 
@@ -621,6 +621,19 @@ def claim(db: DBSession, *, ids: list[str], user_id: str, message_id: str) -> li
 
     Only unclaimed attachments belonging to this user are taken, so a stray or
     forged id cannot pull someone else's file into a conversation.
+
+    **`chat_id` is set here, and it was not.** `POST /api/files` takes one, and
+    the composer sends it -- but only once a chat exists. A file picked on the
+    *new-chat* screen is stored before there is a chat to name, so its
+    `chat_id` stayed NULL for the rest of its life even after the message it
+    belongs to was sent. Six places filter on that column, and every one of them
+    was quietly wrong about those files: the harness did not name them among the
+    attached documents, the canvas refused to open them, and
+    `remove_files_for_chats` could not find them to delete -- so the temporary
+    sweep, the one caller it had, was removing nothing.
+
+    Read from the message rather than passed in, so no caller can bind an
+    attachment to one chat and a message in another.
     """
     if not ids:
         return []
@@ -634,8 +647,11 @@ def claim(db: DBSession, *, ids: list[str], user_id: str, message_id: str) -> li
             )
         )
     )
+    message = db.get(Message, message_id)
     for attachment in pending:
         attachment.message_id = message_id
+        if message is not None:
+            attachment.chat_id = message.chat_id
     db.commit()
     return pending
 

src/lembas/services/schedules.py

@@ -221,7 +221,9 @@ def delete(db: DBSession, schedule: Schedule, *, keep_chat: bool = True) -> None
         if keep_chat:
             chat.kind = "chat"
         else:
-            db.delete(chat)
+            from lembas.services import chat as chat_service
+
+            chat_service.delete_chats(db, [chat])
     db.delete(schedule)
     db.commit()
 

src/lembas/services/subagent.py

@@ -338,9 +338,14 @@ def _cleanup(chat_id: str, *, keep: bool) -> None:
         return
     try:
         with session_scope() as db:
+            from lembas.services import chat as chat_service
+
             chat = db.get(Chat, chat_id)
             if chat is not None:
-                db.delete(chat)
+                # A writing helper can generate an image or attach a file, and
+                # `db.delete` would leave both on disk with the row that named
+                # them gone.
+                chat_service.delete_chats(db, [chat])
     except Exception:  # noqa: BLE001 - tidying up is not the result
         log.debug("could not remove subagent chat %s", chat_id, exc_info=True)
 

src/lembas/services/suggestions.py

@@ -27,32 +27,46 @@ MAX_DESCRIPTION = 300
 MAX_PROMPT = 4000
 
 # A card is sent the moment it is clicked, so each of these has to work cold --
-# with nothing pasted and nothing typed. They are written to ask for what they
-# need, which turns the first reply into the right question rather than a guess
-# at material nobody has given yet.
+# with nothing pasted and nothing typed. These four are *self-contained* rather
+# than question-asking: they are what somebody clicks on an instance they have
+# just stood up, to find out whether the thing works and what the model behind
+# it is. That is the honest first use, and it is a different job from the task
+# cards that preceded them, which opened by asking for material the reader had
+# not given.
+#
+# The name and description are read by somebody who has never seen this
+# instance; the prompt is read by the model. They are allowed to differ, and
+# here they do -- "Start a session" says what the card is for, and its prompt is
+# the bare line that produces a clean opening turn.
+#
+# Only a fresh install gets these: `SEEDED_KEY` means an instance that has
+# already seeded keeps whatever its administrator has since made of the list.
 #
 # No Middle-earth flavour: this is functional UI.
 DEFAULTS: tuple[tuple[str, str, str], ...] = (
     (
-        "Explain this",
-        "Get something confusing back in plain language.",
-        "I want something explained in plain language. Ask me what it is, then "
-        "give me one sentence summarising it, the details that actually matter, "
-        "and anything I should watch out for.",
+        "Start a session",
+        "Open a fresh conversation with nothing assumed.",
+        "Initializing a new session.",
     ),
     (
-        "Draft a reply",
-        "Turn a message you have received into an answer you can send.",
-        "I need to reply to a message. Ask me what it says, what tone I want and "
-        "what outcome I am after, then write a draft I could send as it stands.",
+        "What can you do?",
+        "Have the model say which tools, instructions and limits it has.",
+        "Who are you and what are you capable of? What are your available tools? "
+        "What do you already know from your instructions? Do you have any set "
+        "personality?",
     ),
     (
-        "Find the flaw",
-        "Have a plan argued with before you commit to it.",
-        "I want a plan argued with. Ask me what the plan is, then tell me what is "
-        "most likely to go wrong, what I am assuming without evidence, and what "
-        "would change your mind. Do not soften it, and do not agree just because "
-        "I sound confident.",
+        "Show me some code",
+        "See how the model writes, in a language of its own choosing.",
+        "Pick a random programming language and produce a coding example showing "
+        "your coding capabilities.",
+    ),
+    (
+        "Tell me something",
+        "A fact worth knowing, from a subject picked at random.",
+        "Give me a random fun fact from a random topic of your choosing. "
+        "Available topics are science, history, sociology, theology etc.",
     ),
 )