Narrow a chat before it starts, and find a file rather than spell it

Six things, all found by using the thing rather than by reading it.

The scope menu only appeared once a chat existed, on the reasoning that there was
no row to post to. True, and the wrong conclusion: the harness puts a tool's
guidance in front of the model the moment the tool is offered, so the menu could
not be reached until after the model had been told how to keep notes and handed
the tools to do it -- and switching it off then does not un-send that turn. It is
on the new-chat screen now and writes nothing: `_scope_context` builds a stand-in
Chat, which is `draft.as_chat`'s trick again, and the switches ride along with
the first message. Checked means on and a browser submits only the ticked boxes,
so every gate also renders a hidden input naming it and `start_chat` subtracts one
list from the other; inverting the control would read backwards under a menu that
says everything is on unless you say otherwise. Only the off ones are written,
because absent means on and one representation of it is what keeps "why is this
off?" to a single answer. Nothing is validated against the offered set, since
scope_json narrows after every gate -- naming a gate that was never offered
switches off something that was not on.

Then the scheduling instructions, audited against a 4B model on this machine
rather than against my own reading of them. Ten realistic requests, ten
compiled, twice over -- so the prompt is sound. What was not sound was
`describe`, which built a phrase by joining fragments and read "Every the 1st at
09:00" for the commonest monthly schedule there is, and "Every of January" for a
month with no day. That string is the whole of what somebody sees before
approving a schedule and the whole of what the model is told about its own chat,
so a phrase nobody can parse is a review step nobody performs. It reads as
English now, collapses Monday-to-Friday to "every weekday" and seven days to
"every day", and every case in the test is a rule that model actually produced.

The one mistake it made was naming Wednesday for "every other tuesday", so the
weekday numbering is spelled out rather than left as "0-6, Monday is 0": getting
that wrong is the error here that still looks like a working schedule. Roughly
one call in six also came back empty -- a local runner swapping models under the
request will do that -- so an unusable reply is asked for once more before giving
up. Not on an LLMError: an endpoint that refused will refuse again, and the
reader is better served by the form than by waiting twice for the same answer.

Canvas asked for a typed path, which was the last control in the application
expecting somebody to remember an absolute path on another machine -- the same
complaint the folder page's directory field answered with a picker. /browse takes
pick=file and the same fragment makes files buttons, because a second copy of
that listing is a second place for the path arithmetic to be got subtly
differently. The button carries data-canvas-open rather than an hx-post since the
path is not known until the dialog closes, and ui.js posts it through htmx.ajax
so the response lands in the panel exactly as every other canvas action's does.
The key is `agent:<path>`, so a file opened by hand and one opened by the model
are one tab rather than two spellings of it. The tabs already existed and already
closed; they now square off at the bottom and the active one takes the body's
background, so which is selected is structural rather than a tint nobody can see
in a theme they did not choose. Highlighting was already there for every language
named and is checked for fifteen of them.

Three smaller ones. Tabs kept their scroll position, so switching from a long
panel to a short one left the browser clamping to that panel's bottom: the end of
it above a screen of nothing, which reads as a page that failed to load. Nothing
in CSS can reset a scroll position. The sidebar's footer and the composer sit
either side of one vertical edge and were both content-sized, so their top
borders met it at different heights and read as one line that had been broken --
`--footer-height` is a calc of the pieces the footer is built from, applied as a
min-height to both, which is exactly what `--header-height` already does at the
top of the shell. And "Add a workflow" sat flush against the list it adds to,
stated as an adjacency because `.btn-row` is right to carry no margin everywhere
else it appears.

Both pieces of JavaScript were driven under a DOM stub before committing, which
is how the tab listener's delegation and the canvas button's six behaviours were
checked at all -- `node --check` parses a file that does nothing.

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

tests/test_chat_scope.py

@@ -12,6 +12,7 @@ from __future__ import annotations
 
 import pytest
 from fastapi.testclient import TestClient
+from sqlalchemy import select
 
 from lembas.db.models import Chat, Connection, Model, User
 from lembas.services import settings_store
@@ -322,3 +323,120 @@ def test_with_nothing_to_narrow_there_is_no_button_at_all(
     html = client.get(f"/chat/{chat.id}").text
 
     assert "picker__menu--scope" not in html
+
+
+# --- Before the chat exists -------------------------------------------------------
+def test_the_menu_is_there_before_the_first_message(
+    client: TestClient, db, chat, registered
+):
+    """The bug this section exists for.
+
+    The harness puts a tool's guidance in front of the model the moment the tool
+    is offered — so a menu that only appeared once a chat existed was one you
+    could not reach until after the model had been told how to keep notes and
+    been handed the tools to do it. Switching it off then does not un-send that
+    turn.
+    """
+    settings_store.update(db, {"enabled": True}, key=settings_store.SEARCH)
+    html = client.get("/chat").text
+
+    assert 'aria-label="Toggle"' in html
+    assert 'name="scope_all"' in html
+    assert 'name="scope_on"' in html
+    # And it posts nothing on its own: there is no row to post to yet.
+    assert "/scope" not in html
+
+
+def test_the_prospective_switches_ride_with_the_first_message(
+    client: TestClient, db, chat, registered
+):
+    """A browser submits only the ticked boxes, so "which were unticked" needs
+    the hidden mirror. This asserts the pair exists per gate rather than that
+    the markup looks a certain way."""
+    from html.parser import HTMLParser
+
+    settings_store.update(db, {"enabled": True}, key=settings_store.SEARCH)
+    html = client.get("/chat").text
+
+    named: dict[str, list[str]] = {"scope_all": [], "scope_on": []}
+
+    class Finder(HTMLParser):
+        def handle_starttag(self, tag, attrs):
+            got = {key: (value or "") for key, value in attrs}
+            if got.get("name") in named:
+                named[got["name"]].append(got.get("value", ""))
+
+    Finder().feed(html)
+
+    assert named["scope_all"], "the prospective menu rendered no gates"
+    # Every gate offered has both halves, or one of them can never be turned off.
+    assert set(named["scope_all"]) == set(named["scope_on"])
+
+
+def test_unticking_before_sending_writes_it_to_the_new_chat(
+    client: TestClient, db, chat, registered
+):
+    """End to end: what the menu was set to is what the row is created with, so
+    the very first request is already narrowed."""
+    settings_store.update(db, {"enabled": True}, key=settings_store.SEARCH)
+
+    client.post(
+        "/api/chats/start",
+        data={
+            "content": "hello",
+            "model_id": "m",
+            "scope_all": ["notes", "memory", "web_search"],
+            # `notes` left out: unticked.
+            "scope_on": ["memory", "web_search"],
+        },
+    )
+
+    fresh = db.scalars(
+        select(Chat).where(Chat.user_id == chat.user_id).order_by(Chat.created_at.desc())
+    ).first()
+    assert tools_service.scoped_off(fresh) == frozenset({"notes"})
+    assert "notes_search" not in _names(db, fresh, db.get(User, chat.user_id))
+
+
+def test_leaving_everything_ticked_writes_nothing(client: TestClient, db, chat, registered):
+    """Absent means on, and there is one representation of it. A row full of
+    `True`s would be a second one, and "why is this off?" would have two
+    answers."""
+    client.post(
+        "/api/chats/start",
+        data={
+            "content": "hello",
+            "model_id": "m",
+            "scope_all": ["notes", "memory"],
+            "scope_on": ["notes", "memory"],
+        },
+    )
+
+    fresh = db.scalars(
+        select(Chat).where(Chat.user_id == chat.user_id).order_by(Chat.created_at.desc())
+    ).first()
+    assert fresh.scope_json == {}
+
+
+def test_starting_a_chat_cannot_widen_through_the_menu(
+    client: TestClient, db, chat, registered
+):
+    """The security-shaped half, from the new-chat side. `scope_json` narrows
+    inside `resolve_tools` *after* every gate, so naming a gate that was never
+    offered switches off something that was not on — which is nothing. A
+    crafted POST cannot turn anything on, because there is no representation
+    for "on" to send."""
+    client.post(
+        "/api/chats/start",
+        data={
+            "content": "hello",
+            "model_id": "m",
+            "scope_all": ["agent", "made_up"],
+            "scope_on": ["agent", "made_up"],
+        },
+    )
+
+    fresh = db.scalars(
+        select(Chat).where(Chat.user_id == chat.user_id).order_by(Chat.created_at.desc())
+    ).first()
+    assert "shell_run" not in _names(db, fresh, db.get(User, chat.user_id))