Four features, plus the schema machinery they needed.
**Schema sync.** The first live instance had data in it, and create_all
only creates missing *tables* -- a new column silently never appeared.
db/migrations.py now diffs the declared models against the database and
ALTER TABLE ... ADD COLUMN for what is missing, deriving a backfill
default from the column type (SQLite refuses a NOT NULL column without
one, and a Python-side `default=dict` cannot be expressed in DDL).
Verified against a copy of the live database: eight changes applied, all
rows preserved, second run a no-op. Renames, drops and retypes are still
manual and say so.
**Permissions.** A flat set of named booleans: an instance baseline
widened by each group the user belongs to. A group grants and never
denies -- with denies, "why can this user not do X" cannot be answered
without simulating every group. Admins bypass entirely, because an admin
can grant it back to themselves in two clicks and pretending otherwise
is theatre. Model *access* is separate: public, or granted to groups.
The picker is not the boundary -- switching a chat to a model you cannot
reach is a 403.
**Model settings.** Ordering, pinned-first, an instance default and a
per-user default, display names, descriptions, capability flags, and
uploaded images. Images are stored and served locally rather than by
URL: a remote URL makes every page render a request to a third party.
Uploads are validated by magic number, not the declared content type,
and stored under a random name. Models with no image get a generated
initial whose hue is derived from the model id, so it is stable.
**Reasoning display.** Streams into its own collapsible block above the
answer, labelled "Thought for 14 seconds", collapsed once finished, and
never replayed as context on the next turn. Two sources: the
reasoning_content delta field, and <think> tags inline in content -- the
latter needs a streaming splitter because the tags arrive split across
chunks. Models emitting no reasoning show nothing, via a :has() rule
rather than JavaScript. Verified against qwen35-9b on llama-swap: 694
reasoning events, 52 answer tokens, cleanly separated.
Two bugs found and fixed while testing:
- A bare `Mapped[list]` relationship is treated by SQLAlchemy as a scalar
and returns None instead of []. It needs the element type.
- FastAPI substitutes the default for an empty form value, so with
`x: str | None = Form(None)` a submitted `x=` is indistinguishable from
an absent field. That silently broke clearing a system prompt or a
temperature. update_chat now reads the raw form and checks key presence.
143 tests, ruff clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Establish the LLeMbas foundation: FastAPI/Jinja/SQLite layout, the ORM
schema, and the original SVG identity.
Notable decisions, all recorded in comments at the point they matter:
- No Alembic. SQLite only, schema created at startup, so models carry a
few columns nothing reads yet (Message.parent_id for branching,
content_parts_json for multimodal turns). Adding them later to a live
database without migrations is the painful path.
- Sessions are server-side rows keyed by a SHA-256 of the cookie value,
not JWTs, so logout and bans revoke access immediately.
- Upstream API keys are Fernet-encrypted with a key derived from
LEMBAS_SECRET_KEY. decrypt() fails soft to "" so rotating the secret
degrades to re-entering keys rather than crashing the admin UI.
- Artwork is generated by scripts/build_artwork.py rather than hand-drawn
per file: the mallorn leaf appears in the icon, favicon, lockup and
banner, and one source is the only way those stay in sync. The wordmark
is Source Serif 4 (OFL) converted to outlines, because a README banner
cannot load a webfont and <text> would render in whatever serif the
viewer happens to have.
- Icons live in a template partial, not assets/, because same-document
<use href="#id"> is universally supported and the cross-document form
is not.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Jaroslav Beneš