Drag, paste or pick a file in the composer. Images go to vision models
as multimodal content parts; PDFs and text files have their content
extracted and placed in the prompt. Verified end to end against
gemma4-e4b-q8 on llama-swap: given a drawing and a text file, it named
the red square and blue circle and read the number out of the document.
Type is decided by inspecting the bytes, never the filename or the
browser's Content-Type -- a .png full of text is stored as text. Images
are downscaled to 1400px and re-encoded: a phone photo is several
megabytes of base64, which is slow and a large slice of the context
window. PDF text is extracted once, at upload, and stored; re-extracting
per request would let a reply change because a parser was upgraded.
Design points worth keeping:
- Images are only sent to models an administrator has marked `vision`.
This is not graceful degradation -- most endpoints reject the entire
request rather than ignoring an image part. A plain text turn stays a
plain string for the same reason: the list form 400s on endpoints that
do not implement it.
- Images reach the model as base64 data URIs, not links. A local
endpoint has no route back to LLeMbas, and a hosted one has no
credentials for it.
- Non-images are served Content-Disposition: attachment with nosniff, so
an uploaded .html can never execute in this origin. Stored names are
random; the uploader's name is a label and never a path.
- Uploads are unbound until the message is sent, which is what lets a
file be removed beforehand. claim() only takes unclaimed rows owned by
the sender, so a forged id cannot pull in someone else's file.
Abandoned uploads are swept at startup.
- A scanned PDF says so rather than silently contributing nothing, and
truncation is declared to the model in the document tag so it can
admit it did not see page 400.
- "Here, look at this" with no words is a legitimate turn, so a message
is only empty when it carries neither text nor files.
Also fixes auto-titling, which read message["content"] as a string and
would have broken on the first multimodal turn.
186 tests, ruff clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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>
Two things the running instance needed.
**Registration toggle.** Admin -> General, backed by a new settings table
group rather than the environment. LEMBAS_ALLOW_SIGNUP now seeds only the
initial value: once an administrator saves the setting, the stored value
wins. The alternative -- environment always winning -- means a toggle in
the UI silently reverts on the next restart, which is worse than not
offering one. Closing registration also removes the "Create one" link
from the sign-in page, so the link never leads somewhere that refuses.
**Password change**, on the user settings page. Changing a password
revokes every other session and immediately re-issues a cookie for the
current one: if the reason for the change is that somebody else knows
the password, leaving their session alive defeats the point, but signing
the user out of the tab they are standing in is merely rude.
**deploy/ is now host-agnostic.** This repository is public, so the unit
and vhost became templates with __PREFIX__ / __SITE_HOST__ / __APP_PORT__
substituted at install time, and every path, hostname and port moved to
environment variables. REPO_URL defaults to the checkout's own origin so
a fork deploys itself. Machine-specific values belong in private notes,
not here -- CLAUDE.md now says so.
83 tests, ruff clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
LLeMbas now runs end to end. Register, add an OpenAI-compatible
connection, and hold a real streaming conversation organised into
folders. Verified against the local llama-swap instance.
Streaming is the one genuinely tricky part. Sending a message returns
two HTML fragments -- the user bubble and an empty assistant bubble
carrying an sse-connect -- and that attribute is the ONLY thing that
starts a generation. Rendering an incomplete assistant message as a
streaming shell falls out of the same template, which means loading a
page whose last reply never finished simply picks it up again.
Details worth knowing about, each commented where it matters:
- SSE payloads are split across several data: lines. A raw newline in
one data: line truncates the event, which shows up the first time a
model emits a code block.
- Markdown is rendered server-side by the same helper for both the page
and the final streamed frame, so the two cannot disagree. The fence
renderer is replaced outright rather than using markdown-it's
highlight option, which re-wraps output in a second <pre>.
- escape_text is html.escape, not nh3.clean_text: it escapes character
by character, so escaping stream chunks separately equals escaping
the whole string.
- The stream opens its own session via session_scope(); it outlives the
request handler and the dependency-scoped session may be closed.
- Deleting a folder keeps the chats inside it (FK is SET NULL). Losing
a conversation to a mis-clicked folder delete is unforgivable.
- Login failures use one message for "no such account" and "wrong
password" so the form cannot enumerate registered addresses.
Also adds deploy/ for the gamebox install at https://chat.lan: system
unit, nginx vhost with buffering off (buffering on turns streaming into
one lump at the end), and install/update scripts following the same
service-user and /srv bind-mount conventions as llama-swap and comfyui.
70 tests, ruff clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Jaroslav Beneš