feat(advice): LLM brewing advice on every observation (work in progress)

Stores a model's advice for each recorded reading, in its own field, so the
brewer's own comment is never overwritten.

Fire and forget: the advice is generated in a background thread, so
recording a reading never blocks on the model.  A failure is recorded as a
visible note saying the advice could not be generated, because a silent
failure is indistinguishable from "still thinking".

The model is `glm-5.3:cloud` on the Ollama instance at 192.168.178.45:11434.
Several models on that instance are retired and fail at call time while
still appearing in the model list, so the default is one that was probed.

The system prompt tells the model never to call a reading impossible: a
gravity below 1.000 is always a mis-entry, but the rest of the run may be a
genuine long fermentation and still worth understanding.

150 tests.
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2026-11-09 16:03:29 +10:00
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"""Brewing advice from an LLM, generated for each recorded observation.
The advice is a *comment on the reading*, not a replacement for the
brewer's own comment. Every reading gets its own advice text, stored in
its own field, so nothing the brewer wrote is ever overwritten.
Design notes
------------
- **The LLM is never in the request path.** Recording a reading must not
block on a model that may be slow or down, so the advice is generated in
a background thread and written when it is ready. The page shows the
reading immediately and the advice appears on a later visit.
- **Failures are recorded, not raised.** If the model is unreachable the
advice field gets a short note saying so. A silent failure would look
identical to "no advice yet", which is confusing when you are waiting
for a tip that is never going to arrive.
- **The model is configurable**, with a default that is known to work on
this homelab. Several models on the Ollama instance have been retired
and fail at call time while still appearing in the model list, so the
default is verified rather than assumed.
"""
from __future__ import annotations
import json
import logging
import os
import urllib.error
import urllib.request
log = logging.getLogger(__name__)
#: The Ollama instance on the homelab. Reachable from the pod.
DEFAULT_OLLAMA_URL = os.getenv("OLLAMA_URL", "http://192.168.178.45:11434")
#: A model that is known to work. `deepseek-v4-flash:cloud`,
#: `deepseek-v3.2:cloud` and `qwen3.5:cloud` are all retired and fail at
#: call time, so they are not safe defaults.
DEFAULT_MODEL = os.getenv("OLLAMA_MODEL", "glm-5.3:cloud")
#: How long to wait for the model before giving up. The advice is
#: generated in the background, so this only bounds the background thread.
DEFAULT_TIMEOUT = float(os.getenv("LLM_TIMEOUT", "45"))
#: The advice is advice, not instruction. Keep it short - it has to be
#: readable on the brewing page next to the brewer's own comment.
MAX_ADVICE_CHARS = 1200
SYSTEM_PROMPT = """\
You are an experienced home brewer giving practical advice to a single \
brewer about their own beer. You know brewing science: specific gravity, \
attenuation, yeast health, temperature, timing, and what a stalled or \
struck-out fermentation looks like.
You will be given one brew's readings so far: its name, the original \
gravity, each reading's date and specific gravity, and any comment the \
brewer wrote.
Give the brewer useful, specific, practical advice about THIS reading and \
this brew. Consider things like:
- Is the fermentation progressing at a normal rate for the style and \
temperature?
- Has it stalled, and if so what should they do about it?
- Is the yeast likely stressed, unhealthy, or done?
- Is the gravity drop plausible for the original gravity?
- Should they rack, add more hops, raise the temperature, or wait?
Rules:
- If everything looks normal, say so briefly and say what to expect next.
- If something looks wrong, say what it is and what to do about it.
- Be specific to the numbers given. Do not give generic advice.
- If a reading looks like a typo or a mis-entry, say so and suggest \
checking it, but do not assume it - a slow or long fermentation can be \
genuine.
- Never say a reading is impossible. Beer cannot be denser than water, so \
a gravity below 1.000 is always a mis-entry or a typo, but the rest of the \
run may still be real and worth understanding.
- No preamble, no headings, no bullet-point templates, no "Great question!". \
Write two to five sentences of plain prose.
"""
def _reading_lines(readings: list[dict]) -> str:
"""The readings, as the compact list the model reads."""
lines = []
for r in readings:
parts = [f"- {r.get('date')}: gravity {r.get('sg_decimal')} ({r.get('point_scale')})"]
if r.get("comment"):
parts.append(f"brewer's comment: {r['comment']}")
if r.get("final"):
parts.append("(marked as the FINAL reading)")
lines.append(" ".join(parts))
return "\n".join(lines)
def build_prompt(run: dict, reading: dict, history: list[dict]) -> str:
"""The user-message content for one observation."""
name = run.get("canonical_name") or run.get("name") or "this brew"
og = run.get("og_decimal")
if og is None and run.get("og_points"):
og = f"{run['og_points'] / 1000:.3f}"
parts = [
f"Beer: {name}",
]
if og:
parts.append(f"Original gravity: {og}")
if run.get("tap_number"):
parts.append(f"Fermenter tap: {run['tap_number']}")
if run.get("notes"):
parts.append(f"Brewer's notes: {run['notes']}")
parts.append("")
parts.append("Readings so far (oldest first):")
parts.append(_reading_lines(history))
parts.append("")
parts.append("Give advice for the most recent reading.")
return "\n".join(parts)
def call_ollama(prompt: str, *, url: str | None = None, model: str | None = None,
timeout: float | None = None) -> str:
"""Ask the model for advice. Raises on failure."""
base = (url or DEFAULT_OLLAMA_URL).rstrip("/")
chosen_model = model or DEFAULT_MODEL
wait = timeout if timeout is not None else DEFAULT_TIMEOUT
payload = json.dumps({
"model": chosen_model,
"messages": [
{"role": "system", "content": SYSTEM_PROMPT},
{"role": "user", "content": prompt},
],
"temperature": 0.4,
# The reasoning models emit their thinking first, and it comes out
# of the same budget. At 500 tokens the reasoning used the whole
# allowance and the reply came back empty - which looked like a
# broken model rather than a budget problem. 2000 leaves room for
# the reasoning AND the advice.
"max_tokens": 2000,
"stream": False,
}).encode("utf-8")
request = urllib.request.Request(
f"{base}/v1/chat/completions",
data=payload,
headers={"Content-Type": "application/json"},
method="POST",
)
with urllib.request.urlopen(request, timeout=wait) as response:
body = json.loads(response.read().decode("utf-8"))
choices = body.get("choices") or []
if not choices:
raise RuntimeError("the model returned no choices")
content = (choices[0].get("message") or {}).get("content") or ""
content = content.strip()
if not content:
raise RuntimeError("the model returned an empty response")
return content[:MAX_ADVICE_CHARS]
def generate_advice(run: dict, reading: dict, history: list[dict], *,
url: str | None = None, model: str | None = None,
timeout: float | None = None) -> tuple[bool, str]:
"""Generate the advice for one reading.
Returns ``(ok, text)``. On failure ``ok`` is False and ``text`` is a
short note explaining what went wrong, so the reading carries a
visible reason instead of silently having no advice.
"""
prompt = build_prompt(run, reading, history)
try:
return True, call_ollama(prompt, url=url, model=model, timeout=timeout)
except urllib.error.HTTPError as exc:
# HTTPError is a subclass of URLError, so it has to be caught
# FIRST or it would be swallowed by the unreachable branch.
detail = ""
try:
detail = exc.read().decode("utf-8", "replace")[:300]
except Exception:
pass
log.warning("the model returned HTTP %s: %s", exc.code, detail)
return False, (f"Advice could not be generated - the model returned "
f"HTTP {exc.code}. {detail}".strip())
except urllib.error.URLError as exc:
log.warning("the model was unreachable: %s", exc)
return False, "Advice could not be generated - the model was unreachable."
except TimeoutError:
log.warning("the model timed out")
return False, "Advice could not be generated - the model timed out."
except Exception as exc: # noqa: BLE001 - the caller must never crash
log.warning("advice generation failed: %s", exc)
return False, f"Advice could not be generated - {exc}"
def generate_advice_in_background(run: dict, reading: dict,
history: list[dict], writer) -> None:
"""Generate the advice and hand it to *writer* when it is ready.
*writer* is called as ``writer(reading_id, ok, text)``. It runs in a
background thread, so it must not touch the request context - the
caller is responsible for giving it a way to reach Mongo.
"""
ok, text = generate_advice(run, reading, history)
try:
writer(reading.get("_id"), ok, text)
except Exception: # noqa: BLE001 - never let the thread die noisily
log.exception("could not store the generated advice")
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@@ -152,6 +152,10 @@ class Reading:
comment: str = ""
beer_type: str = ""
_id: str = ""
# The LLM's advice for this reading. It lives in its own field in
# Mongo, so the brewer's own comment is never overwritten.
advice: str = ""
advice_ok: bool = True
@property
def sg_decimal(self) -> float | None:
@@ -171,6 +175,8 @@ class Reading:
comment=(doc.get("comment") or "").strip(),
beer_type=(doc.get("beer_type") or "").strip(),
_id=str(doc.get("_id") or ""),
advice=(doc.get("advice") or "").strip(),
advice_ok=bool(doc.get("advice_ok", True)),
)
@@ -189,6 +195,25 @@ class Run:
# -- aggregate accessors ------------------------------------------------ #
def latest_advice(self) -> str:
"""The advice for the most recent reading that has any.
The advice is generated in the background, so the newest reading
may not have any yet - in which case the newest one that does is
used, rather than showing nothing.
"""
for reading in reversed(self.readings):
if reading.advice:
return reading.advice
return ""
def latest_advice_ok(self) -> bool:
"""False when the advice is a note saying it could not be generated."""
for reading in reversed(self.readings):
if reading.advice:
return reading.advice_ok
return True
def sg_values(self) -> list[int]:
"""Gravity points of every *usable* reading, in chronological order."""
return [r.sg_points for r in self.readings if r.sg_points is not None]
@@ -622,6 +647,10 @@ def run_summary(run: Run, today: date | None = None,
"days_in_fermenter": run.days_in_fermenter(today),
"comments": run.comments(),
"last_comment": run.comments()[-1] if run.comments() else "",
# The advice the LLM gave for the most recent reading, if it has
# arrived yet.
"advice": run.latest_advice(),
"advice_ok": run.latest_advice_ok(),
"attenuation": attenuation_percent(run),
"curve": fermentation_curve(run),
"outliers": [r.sg_points for r in run.outlier_readings()],
@@ -633,6 +662,8 @@ def run_summary(run: Run, today: date | None = None,
"final_reading": r.final_reading,
"comment": r.comment,
"beer_type": r.beer_type,
"advice": r.advice,
"advice_ok": r.advice_ok,
}
for r in run.readings
],
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@@ -188,6 +188,27 @@ class BeerRepository:
existing = self.readings.find_one(query)
return str(existing.get("_id")) if existing else ""
def set_reading_advice(self, reading_id: str, advice: str,
ok: bool = True) -> int:
"""Attach the LLM's advice to a reading.
The advice lives in its own field, so the brewer's own comment is
never overwritten. ``ok`` says whether the advice was actually
generated or is a note explaining that it could not be.
"""
doc_id = _as_doc_id(reading_id)
if doc_id is None:
return 0
result = self.readings.update_one(
{"_id": doc_id},
{"$set": {
"advice": str(advice),
"advice_ok": bool(ok),
"advice_at": _now_iso(),
}},
)
return result.modified_count
def set_final_reading(self, beer_run_id: str, reading_date: str,
final: bool) -> int:
"""Flag (or unflag) a reading as the final reading of its run."""
@@ -314,6 +335,28 @@ def _as_id(value: object) -> str:
return ""
def _as_doc_id(value: object):
"""Coerce a reading document id to something Mongo will match.
The ``_id`` of a reading is an ``ObjectId``, not a run id, so the
``_as_id`` coercion does not apply - it would turn the ObjectId into
an empty string and the update would silently match nothing.
Only an ObjectId or a plain string is accepted, so a dict can never
be injected as a query operator.
"""
from bson import ObjectId
if isinstance(value, ObjectId):
return value
if isinstance(value, str):
try:
return ObjectId(value)
except Exception:
return None
return None
def _as_date(value: object) -> str:
"""Coerce a reading date to a plain ``YYYY-MM-DD`` string."""
if isinstance(value, str):
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@@ -689,3 +689,65 @@ table.data .comment { color: var(--text-muted); font-size: .84rem; }
.reading-list__sg { font-family: var(--mono); font-weight: 650; flex: 0 0 4rem; }
.reading-list__body { flex: 1; min-width: 0; }
.reading-list__comment { color: var(--text-muted); font-size: .84rem; }
/* ------------------------------------------------------------- advice */
/* The LLM's advice. It sits next to the brewer's own comment, never
replaces it, and is visually distinct so the two are never confused. */
.advice {
display: block;
margin-top: .35rem;
padding: .5rem .65rem;
border-left: 2px solid var(--amber);
border-radius: 0 4px 4px 0;
background: var(--amber-dim);
color: var(--text);
font-size: .8125rem;
line-height: 1.5;
}
.advice__label {
display: block;
margin-bottom: .15rem;
font-size: .625rem;
font-weight: 600;
letter-spacing: .08em;
text-transform: uppercase;
color: var(--amber-text);
}
/* Advice that could not be generated - it says why. */
.advice--failed {
border-left-color: var(--danger);
background: var(--danger-dim);
color: var(--text-muted);
}
.advice--failed .advice__label {
color: var(--danger);
}
.advice-cell {
max-width: 32rem;
}
/* In the table the advice is clamped to a few lines - the full text is
on the run detail page, where there is room to read it. */
.advice-cell .advice {
margin-top: 0;
font-size: .75rem;
display: -webkit-box;
-webkit-line-clamp: 4;
line-clamp: 4;
-webkit-box-orient: vertical;
overflow: hidden;
}
/* The clamped text opens up on hover, so the whole thing is readable
without leaving the page. */
.advice-cell:hover .advice,
.advice-cell:focus-within .advice {
-webkit-line-clamp: unset;
line-clamp: unset;
overflow: visible;
}
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@@ -100,6 +100,13 @@
</div>
{% endif %}
{% if run.advice %}
<div class="advice advice--reading{% if not run.advice_ok %} advice--failed{% endif %}">
<span class="advice__label">Brewing advice</span>
{{ run.advice }}
</div>
{% endif %}
<div class="btn-row">
<a class="btn btn--ghost btn--sm"
href="{{ url_for('brews.run_detail', run_id=run.beer_run_id) }}">Open run</a>
+8
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@@ -83,6 +83,7 @@
<th class="num">Gravity</th>
<th class="num">Est. ABV</th>
<th>Comment</th>
<th>Brewing advice</th>
<th></th>
</tr>
</thead>
@@ -111,6 +112,13 @@
<span class="faint">—</span>
{% endif %}
</td>
<td class="comment advice-cell">
{% if run.advice %}
<span class="advice{% if not run.advice_ok %} advice--failed{% endif %}">{{ run.advice }}</span>
{% else %}
<span class="faint">Thinking…</span>
{% endif %}
</td>
<td class="right">
<a class="btn btn--ghost btn--sm"
href="{{ url_for('brews.run_detail', run_id=run.beer_run_id) }}">Open</a>
+6
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@@ -144,6 +144,12 @@
{% else %}
<div class="faint tiny">No comment</div>
{% endif %}
{% if reading.advice %}
<div class="advice advice--reading{% if not reading.advice_ok %} advice--failed{% endif %}">
<span class="advice__label">Brewing advice</span>
{{ reading.advice }}
</div>
{% endif %}
</div>
{% if reading.final_reading %}
<span class="chip chip--done">Final</span>
+93 -4
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@@ -2,15 +2,22 @@
from __future__ import annotations
from flask import (Blueprint, flash, jsonify, redirect, render_template,
request, session, url_for)
import logging
import os
import threading
from flask import (Blueprint, current_app, flash, jsonify, redirect,
render_template, request, session, url_for)
from flask_wtf import FlaskForm
from wtforms import (BooleanField, DateField, IntegerField, StringField,
SubmitField, TextAreaField)
from wtforms.validators import DataRequired, Length, NumberRange, Optional
import brew_advice
from brewing import implausible_runs, is_plausible_sg, run_summary
log = logging.getLogger(__name__)
bp = Blueprint("brews", __name__)
@@ -34,6 +41,82 @@ def login_required(fn):
return wrapper
def advice_enabled() -> bool:
"""Whether the LLM advice should be generated.
It is off in testing, so the suite never reaches out to a model, and
it can be turned off in production with ``LLM_ADVICE=0`` if the model
is misbehaving.
"""
if current_app.config.get("TESTING"):
return False
return os.getenv("LLM_ADVICE", "1").strip().lower() not in {"0", "false", "no"}
def _start_advice(run_id: str, reading_id: str) -> None:
"""Generate the LLM's advice for a reading, in the background.
The advice is a separate field on the reading, so the brewer's own
comment is never touched.
The background thread cannot use the request-scoped repository - that
client is closed when the request ends - so it builds its own.
"""
if not reading_id:
return
if not advice_enabled():
return
try:
repository = repo()
run = repository.run(run_id)
if run is None:
return
meta = repository.run_metadata(run_id)
summary = run_summary(run, og_override=meta.get("og_points"))
run_info = {
"canonical_name": meta.get("name") or run.display_name(),
"name": run.display_name(),
"og_points": summary.get("og_points"),
"og_decimal": summary.get("og_decimal"),
"tap_number": meta.get("tap_number"),
"notes": meta.get("notes", ""),
}
# The model's view of the run: every reading, with the gravity in
# both forms a brewer would recognise.
readings = []
for reading in run.readings:
points = reading.sg_points
readings.append({
"_id": reading._id,
"date": reading.date.isoformat() if reading.date else "",
"sg": points,
"sg_decimal": reading.sg_decimal,
"point_scale": f"{points} points" if points is not None else "",
"comment": reading.comment or "",
"final": bool(reading.final_reading),
})
latest = dict(readings[-1]) if readings else {"date": "", "sg": None}
latest["_id"] = reading_id
except Exception: # noqa: BLE001 - advice must never break the save
log.exception("could not gather the reading for the advice")
return
def write(read_id: str, ok: bool, text: str) -> None:
from mongo.repository import BeerRepository
BeerRepository().set_reading_advice(read_id, text, ok)
thread = threading.Thread(
target=brew_advice.generate_advice_in_background,
args=(run_info, latest, readings, write),
daemon=True,
)
thread.start()
def _last_reading_date(run) -> str | None:
"""The ISO date of the most recent reading in a run."""
last = run.last_reading()
@@ -104,8 +187,9 @@ def index():
"(990-1200). It was saved anyway — double-check the reading.",
"warning",
)
repo().upsert_reading(
beer_run_id=str(form.beer_run_id.data),
run_id = str(form.beer_run_id.data)
reading_id = repo().upsert_reading(
beer_run_id=run_id,
beer_type=(form.beer_run_type.data or "").strip(),
sg=sg_points,
reading_date=form.Date.data.isoformat(),
@@ -113,6 +197,11 @@ def index():
comment=(form.comment.data or "").strip(),
)
flash("Reading saved.", "success")
# The advice is generated in the background: recording a reading
# must not block on the model. The page shows the reading straight
# away and the advice is there on a later visit.
_start_advice(run_id, reading_id)
return redirect(url_for("brews.index"))
runs = repo().runs()