The menu that never appeared, and the reason it never did

composer.js built its menu lazily inside show(), and refresh() wrote
list.innerHTML before calling it. `list` is null until build() has run, so the
first `/` or `@` ever typed threw a TypeError and took the handler with it. The
menu has never appeared in any browser. That is why /compact "isn't there":
nothing was. I shipped it having only run `node --check`, which parses the file
happily.

So this also brings the thing that catches it: a DOM stub driven under node --
not committed, hard rule 1 stands, it is an instrument like curl. It reproduced
the crash in one run and immediately found two more: choosing a command from the
menu left `/help` sitting in the box so the next Enter ran it again, and Tab
completed nothing. Tab now completes and Enter runs, which is the split that
matters for a command taking an argument.

`.select--sm` was used three times and defined nowhere. I deleted the copy in
chat.css and left a comment saying it "is defined once, in app.css", where it
did not exist -- so those selects fell back to plain `.select`: width 100% in a
flex row where four siblings wanted the same, all of them shrinking together
until each was a few characters wide, and half a rem taller than everything
beside them. That was the whole of "the connection switch needs to be wider".

The connection and directory move to the topbar. They cannot change -- update_chat
refuses both with a 409 -- so they are facts about the chat, of a kind with the
Temporary badge, not controls on the message. The mode stays by the box.

Compaction says it is working. It makes a model call that takes seconds and had
no indicator anywhere: `hx-indicator` appears nowhere in this codebase, and the
Generation.status channel that says "Summarising earlier messages…" for the
automatic path cannot be borrowed, because it lives in the streaming bubble and
this endpoint refuses to run while any message is unfinished. The overflow menu
now runs the same code as /compact rather than posting for itself, so there is
one implementation, one spinner, and one place the endpoint's four carefully
written 409s finally reach somebody.

/effort, low medium high, per chat with a per-model default. It goes out twice
because there is no field that works everywhere: OpenAI and vLLM read
reasoning_effort, llama.cpp's own docs say other values "have no effect" and its
maintainer says the field "simply gets dropped without error or logging" -- what
reaches gpt-oss behind it is chat_template_kwargs. Both are sent, and only once
an effort has been chosen, so a provider strict about unknown parameters sees
exactly the request it always did until somebody opts in. The control appears
only on a model marked `reasoning`, a flag that has existed since the beginning
with no reader at all.

Mentions and recognised commands are marked as you type -- a mirror behind the
textarea holding the same text with every character transparent, contributing
nothing but a rounded rectangle, so a pixel of drift is a misplaced rectangle
rather than a doubled glyph. A command is marked only when it resolves, so
`/thoughts on this` visibly is not one before you send it. And again in the
transcript, where user turns had no render step at all and now escape before
they inject.

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

tests/test_effort.py

@@ -0,0 +1,164 @@
+"""Reasoning effort: what goes out, and what does not.
+
+The second half matters as much as the first. There is no field that works
+everywhere -- OpenAI and vLLM read `reasoning_effort`, llama.cpp drops it
+silently and reads only `chat_template_kwargs` -- so both are sent. That is only
+safe because neither is sent at all until somebody chooses an effort, which is
+what keeps an endpoint strict about unknown parameters working exactly as it
+did.
+"""
+
+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 chat as chat_service
+
+
+def _model(db, **capabilities) -> Model:
+    connection = Connection(name="c", base_url="http://127.0.0.1:1", api_key_encrypted="")
+    db.add(connection)
+    db.commit()
+    model = Model(
+        connection_id=connection.id,
+        model_id="m",
+        capabilities_json={"reasoning": True, **capabilities},
+    )
+    db.add(model)
+    db.commit()
+    return model
+
+
+def _chat(db, effort: str | None = None) -> Chat:
+    model = _model(db)
+    user = db.scalars(select(User)).first()
+    chat = Chat(
+        user_id=user.id,
+        model_id=model.model_id,
+        connection_id=model.connection_id,
+        params_json={"reasoning_effort": effort} if effort is not None else {},
+    )
+    db.add(chat)
+    db.commit()
+    return chat
+
+
+# --- What reaches the endpoint -----------------------------------------------
+def test_an_effort_goes_out_in_both_forms(client: TestClient, db, registered):
+    """One value, two fields. Neither endpoint family reads the other's."""
+    chat = _chat(db, "high")
+
+    body = chat_service.build_request(db, chat)
+
+    assert body["reasoning_effort"] == "high"
+    assert body["chat_template_kwargs"] == {"reasoning_effort": "high"}
+
+
+def test_no_effort_means_neither_field(client: TestClient, db, registered):
+    """The whole safety of sending both. A chat nobody has set an effort on is
+    byte-for-byte the request it was before this existed, so a provider that
+    refuses unknown parameters is untouched until somebody opts in."""
+    chat = _chat(db)
+
+    body = chat_service.build_request(db, chat)
+
+    assert "reasoning_effort" not in body
+    assert "chat_template_kwargs" not in body
+
+
+def test_a_cleared_effort_means_neither_field(client: TestClient, db, registered):
+    """Cleared is stored as None, like every other parameter here."""
+    chat = _chat(db, None)
+
+    body = chat_service.build_request(db, chat)
+
+    assert "reasoning_effort" not in body
+
+
+@pytest.mark.parametrize("junk", ["sudo", "HIGH ", "maximum", "1"])
+def test_a_value_that_is_not_an_effort_is_not_sent(client: TestClient, db, registered, junk):
+    """Never trusted from the row: it could predate a change to the list."""
+    chat = _chat(db, junk)
+
+    assert "reasoning_effort" not in chat_service.build_request(db, chat)
+
+
+def test_existing_chat_template_kwargs_are_kept(client: TestClient, db, registered):
+    """Merged rather than replaced, so a future caller setting something else
+    there does not lose it."""
+    body: dict = {"chat_template_kwargs": {"enable_thinking": True}}
+
+    chat_service.apply_effort(body, "low")
+
+    assert body["chat_template_kwargs"] == {"enable_thinking": True, "reasoning_effort": "low"}
+
+
+# --- Setting it ---------------------------------------------------------------
+def test_patching_the_effort_stores_it(client: TestClient, db, registered):
+    chat = _chat(db)
+
+    assert client.patch(
+        f"/api/chats/{chat.id}", data={"reasoning_effort": "medium"}
+    ).status_code == 204
+
+    db.refresh(chat)
+    assert chat.params_json["reasoning_effort"] == "medium"
+
+
+def test_an_empty_effort_clears_it(client: TestClient, db, registered):
+    chat = _chat(db, "high")
+
+    client.patch(f"/api/chats/{chat.id}", data={"reasoning_effort": ""})
+
+    db.refresh(chat)
+    assert chat.params_json["reasoning_effort"] is None
+
+
+def test_an_unknown_effort_leaves_the_old_one(client: TestClient, db, registered):
+    """Ignored, not refused: a typo should not cost the setting you had."""
+    chat = _chat(db, "low")
+
+    client.patch(f"/api/chats/{chat.id}", data={"reasoning_effort": "extreme"})
+
+    db.refresh(chat)
+    assert chat.params_json["reasoning_effort"] == "low"
+
+
+def test_the_control_only_appears_on_a_reasoning_model(client: TestClient, db, registered):
+    """The flag has existed with no reader since the beginning; this is its
+    first job. Offering the control everywhere would offer a setting that does
+    nothing almost everywhere."""
+    chat = _chat(db)
+    assert "data-effort" in client.get(f"/chat/{chat.id}").text
+
+    model = db.scalars(select(Model)).one()
+    model.capabilities_json = {"reasoning": False}
+    db.commit()
+
+    assert "data-effort" not in client.get(f"/chat/{chat.id}").text
+
+
+# --- The per-model default ----------------------------------------------------
+def test_a_new_chat_starts_from_the_models_defaults(client: TestClient, db, registered):
+    """`Model.params_json` has claimed to do this since it was added and did it
+    nowhere. It is empty on every existing row, so honouring it changes nothing
+    until an administrator sets something."""
+    model = _model(db)
+    model.params_json = {"reasoning_effort": "high"}
+    db.commit()
+
+    client.post("/api/chats/start", data={"content": "hello", "model_id": "m"})
+
+    chat = db.scalars(select(Chat)).one()
+    assert chat.params_json["reasoning_effort"] == "high"
+
+
+def test_a_model_with_no_defaults_starts_a_plain_chat(client: TestClient, db, registered):
+    _model(db)
+
+    client.post("/api/chats/start", data={"content": "hello", "model_id": "m"})
+
+    assert db.scalars(select(Chat)).one().params_json == {}