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FabledScribe/src/scribe/services/embeddings.py
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feat(retrieval): every semantic search hands on the passage that matched
#4243 fixed one door. Scribe has three semantic searches over three chunk
tables, and all three collapsed chunk rows to the best one per record — each
of them KNEW which passage earned the hit, and each dropped it. Every surface
downstream then previewed the head of the document instead: a span the search
had already scored lower, with nothing saying so.

Mechanism, one place:
  - embeddings.record_best_chunk publishes {id: {index, text}} into `report`.
    Carried in `report`, NOT the return value: all three return
    list[tuple[float, Record]] and ~30 sites unpack that pair (lesson #4207).
  - semantic_search_rules and semantic_search_milestones now select
    chunk_index/chunk_text and publish the winner, as notes already did.
    semantic_search_milestones gains `report`, which it had no way to take.
  - services/text.matched_excerpt is the one choice of span, and
    excerpt_fields the one result block. Doors keep their own field names —
    the web renders `snippet`, MCP returns `excerpt` — because renaming a
    field a frontend reads is a different change from fixing what goes in it.

Surfaces:
  - knowledge.query_knowledge, whose own comment calls it "the human's MAIN
    search surface", was `(note.body or "")[:200]` on every row alike. Now the
    matched passage on a search, the opening on a browse, and `snippet_is`
    saying which. KnowledgeView renders that snippet, so this was live.
  - search(content_type='milestone') gains `matched` — the plan body stays
    out, but the passage that matched comes along, because recognising a plan
    means recognising the part you asked about and a description written at
    the start need not mention it.
  - The auto-inject menu and the write-path prior-art menu put the passage
    under their line. Both were title-only, which answers "does this apply?"
    for a lesson or snippet (the trigger is IN the title) and not at all for
    an issue or dev-log. No fallback to the body's opening: on a menu that is
    preamble dressed as a reason, and once indented it cannot be told apart.

Left alone deliberately: the rule arms. A rule hint already renders the rule's
TRIGGER, which is written to answer exactly "does this apply to me" and beats
a matched chunk at it; and that line's budget was measured at #3851. Adding a
passage there would duplicate the trigger and spend the budget twice.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy
2026-09-21 09:44:10 -04:00

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"""Semantic note search via fastembed (in-process ONNX, no external service).
Embeddings are stored as JSONB lists in the note_embeddings table (one row per
note). All search operations degrade gracefully — if the embedder fails to
initialize the callers fall back to keyword search.
Model: BAAI/bge-small-en-v1.5 (384-dim). The first call downloads the model
into `FASTEMBED_CACHE_DIR` (defaults to /data/fastembed-cache, a mounted
volume so subsequent boots are instant).
"""
import asyncio
import logging
import math
import os
from collections.abc import Sequence
from typing import TYPE_CHECKING
from sqlalchemy import delete, or_, select
from scribe.models import async_session
from scribe.models.embedding import NoteEmbedding, RuleEmbedding
from scribe.models.note import Note
from scribe.services.access import can_read_project, notes_visibility_clause
if TYPE_CHECKING: # resolves forward refs without importing at runtime
from scribe.models.milestone import Milestone
from scribe.models.rulebook import Rule
logger = logging.getLogger(__name__)
# Minimum cosine similarity to include a note in context results.
# bge-small-en-v1.5 produces unit-normalized vectors, so range is [-1, 1].
# 0.45 keeps only genuinely relevant notes; lower values like 0.30 let in
# loosely-related results that pad the sidebar without adding real value.
_SIMILARITY_THRESHOLD = 0.45
# The floor for INTERACTIVE, human-facing feeds — REST /api/search, Browse
# search, and the list views' semantic `q`. Deliberately looser than the agent
# default above: a human scanning a result list gets value from loosely-related
# hits an agent would be misled by. One constant, because this number was
# written as `0.3` in two files with the reasoning attached to only one of
# them — the exact shape where a later tuner moves one and not the other
# (#2463 finding 3).
INTERACTIVE_SEARCH_THRESHOLD = 0.3
# Public alias so callers (and telemetry) can record the effective default
# threshold without reaching for the underscored name.
DEFAULT_SIMILARITY_THRESHOLD = _SIMILARITY_THRESHOLD
_MODEL_NAME = "BAAI/bge-small-en-v1.5"
_CACHE_DIR = os.environ.get("FASTEMBED_CACHE_DIR", "/data/fastembed-cache")
_model = None # lazy singleton; first call downloads model files
_model_lock = asyncio.Lock()
async def _get_model():
"""Return the singleton fastembed.TextEmbedding instance, loading on first call."""
global _model
if _model is None:
async with _model_lock:
if _model is None:
# Defer the import so module import doesn't pull in onnxruntime
# for non-embedding code paths (cheaper cold-start for tests etc.)
from fastembed import TextEmbedding
_model = await asyncio.to_thread(
TextEmbedding,
model_name=_MODEL_NAME,
cache_dir=_CACHE_DIR,
)
logger.info("Loaded fastembed model %s (cache: %s)", _MODEL_NAME, _CACHE_DIR)
return _model
async def get_embedding(text: str) -> list[float]:
"""Get an embedding vector for the given text.
Raises if the fastembed model fails to load. Callers should catch and
degrade to keyword search.
"""
return (await get_embeddings([text]))[0]
async def get_embeddings(texts: list[str]) -> list[list[float]]:
"""Embed several texts in one model call (the chunked write path).
fastembed batches internally, so N chunks cost far less than N single
calls. Raises like get_embedding; callers catch and degrade.
"""
embedder = await _get_model()
# embed() is synchronous CPU work; offload so we don't block the event loop.
vecs = await asyncio.to_thread(lambda: list(embedder.embed(texts)))
return [v.tolist() for v in vecs]
def _cosine_similarity(a: list[float], b: list[float]) -> float:
"""Cosine similarity between two vectors. Returns 0 for zero-length or
mismatched-length inputs (defensive — mixed-dim vectors can sneak in
across the migration boundary)."""
if not a or not b or len(a) != len(b):
return 0.0
dot = sum(x * y for x, y in zip(a, b))
mag_a = math.sqrt(sum(x * x for x in a))
mag_b = math.sqrt(sum(x * x for x in b))
if mag_a == 0.0 or mag_b == 0.0:
return 0.0
return dot / (mag_a * mag_b)
# How much a superseded record is pushed down the ranking (#278).
#
# Chosen against a measurement, not by feel. On 2026-08-07 dev-log #2420 sat at
# 0.6120 on a query made of its own title phrase, 8th, behind #1759 at 0.6506 —
# a deficit of 0.039 to the top and ~0.014 to its nearest neighbours. A penalty
# of 0.05 clears that whole band, so demoting a cluster's stale members actually
# reorders it rather than shuffling within a tie.
#
# It is deliberately NOT large. Supersession is a claim about SOME of a record's
# content, so a superseded note that strongly answers a question nothing else
# answers should still surface — just behind anything comparable that is
# current. A penalty big enough to bury it outright would be hiding by another
# name, which is the thing the operator ruled out.
_SUPERSESSION_PENALTY = 0.05
# Candidates fetched per requested result when a re-rank follows. Three ranks of
# headroom is far more than a 0.05 penalty can move anything through in a corpus
# whose neighbours sit ~0.01-0.02 apart.
_SUPERSESSION_OVERFETCH = 3
# Chunk rows fetched per requested result (#280). The HNSW top-k runs at CHUNK
# grain — several chunks of one strong note can occupy consecutive ranks, and
# each collapses into a single result. Four ranks of headroom per result keeps
# the top-k indexed while making it effectively impossible for collapsing to
# starve the result list: that would need every requested note to be shadowed
# by four chunks of notes ranked above it.
_CHUNK_OVERFETCH = 4
async def _apply_supersession_penalty(
scored: list[tuple[float, "Note"]], limit: int
) -> list[tuple[float, "Note"]]:
"""Push superseded records below their equals, then take the top `limit`.
The penalty is applied to the RANKING score and the returned score, so
downstream gates see the adjusted value — the auto-inject margin band in
particular, which exists to stop near-ties dragging in neighbours and would
otherwise re-tie exactly what this just separated.
It is NOT applied to the relevance threshold: the floor decides whether a
record is relevant at all, the penalty decides which relevant record comes
first. Applying it to the floor would drop a superseded record out of the
results entirely — hiding, which is the one thing this must not do.
Stable within a tie: Python's sort preserves the distance order the database
already established, so equal-scoring records keep their original sequence
rather than reshuffling per call.
"""
if not scored:
return []
from scribe.services.supersession import superseded_ids
try:
stale = await superseded_ids([int(note.id) for _score, note in scored])
except Exception:
# Fail OPEN, and the direction matters: ranking without the penalty is
# the behaviour that shipped for months. Returning nothing, or raising,
# would turn a supersession-lookup hiccup into a broken search.
logger.warning("Supersession lookup failed — ranking unpenalised", exc_info=True)
return scored[:limit]
if not stale:
return scored[:limit]
adjusted = [
(score - _SUPERSESSION_PENALTY if int(note.id) in stale else score, note)
for score, note in scored
]
adjusted.sort(key=lambda pair: pair[0], reverse=True)
return adjusted[:limit]
def embedding_text(title: str | None, body: str | None) -> str:
"""`title\\n{body}` — the atomic join every embedded document is built from.
One definition, deliberately. This was written out three times — the write
path (`notes.embed_note`), the recurring-task spawn, and the startup
backfill — and identical copies of a formatting rule are three chances to
change one and not the others. The spawn path is the dangerous one: a
recurring task embedded to a different shape than everything else would be
ranked against a corpus it doesn't match, and nothing would report it.
Since the chunking build (#280) this is a BUILDING BLOCK, not the whole
story: the document shape a record is embedded as is `chunk_document`
below, which calls this once per chunk. Callers that want "the text this
note is embedded as" want `chunk_document`; this stays public because the
two functions are one contract and the guard in test_embedding_text pins
both.
"""
title = title or ""
body = body or ""
return f"{title}\n{body}".strip() if body else title
# The join between a situation-keyed record's subject and its trigger. A
# CONSTANT because `untrigger_title` below has to spell the same thing to undo
# it, and two literals that must match are one edit away from not matching.
TRIGGER_SEP = " — "
def trigger_title(subject: str | None, trigger: str | None) -> str:
"""`{subject}{trigger}` — the title half of a situation-keyed document.
ONE definition, because this join had three. `rule_document` built it for
rules, `snippets.compose_title` for snippets, and milestone 385 needed a
fourth for lessons — the shape #3207 records, where a fix or an improvement
then has to be found in N places by someone who does not know N.
WHY THE JOIN MATTERS AT ALL, measured in note #2485: the snippet was the
only sharp record in the corpus — a 0.153 top-to-second gap against
0.0100.023 for everything else — and the cause was this title plus the
same trigger repeated in the body, so purpose appears twice in a short
document and dominates the vector. Every kind that must be findable by WHEN
IT APPLIES rather than what it is about is built on this line.
Either side alone is returned as-is: a record with no trigger yet degrades
to its subject and still embeds, just less sharply — which is an argument
for backfilling triggers, not for padding the title with whatever text is
to hand.
"""
subject = (subject or "").strip()
trigger = (trigger or "").strip()
if subject and trigger:
return f"{subject}{TRIGGER_SEP}{trigger}"
return subject or trigger
def untrigger_title(title: str | None, trigger: str | None) -> str:
"""The subject back out of a `trigger_title` — the inverse of the join.
Kept HERE, beside the join, for the reason the join itself was
consolidated: a separator spelled in two files is a separator that will one
day be changed in one of them. #3207 records the shape — derive it before
the third copy — and an inverse written in a caller is that third copy
wearing a different name.
Needs the trigger passed in rather than guessing at the separator, because
a subject may legitimately contain an em dash. Given the trigger, the
suffix is exact and the split cannot be wrong.
Degrades to the whole title when the suffix is absent — a record written
before the join existed, or one with no trigger yet, still answers with
something a human recognises rather than with "".
"""
title = (title or "").strip()
trigger = (trigger or "").strip()
if not trigger:
return title
suffix = f"{TRIGGER_SEP}{trigger}"
if title.endswith(suffix):
return title[: -len(suffix)].strip()
return title
# --- chunking (#280): the document shape ------------------------------------
#
# bge-small reads at most 512 tokens and fastembed silently truncates the rest,
# so a single whole-document vector loses everything past ~400 words — for a
# long dev-log, three quarters of the record was PERMANENTLY invisible to
# search. The fix is the document shape: one vector per meaningful chunk, and a
# record is as findable as its best-matching section.
# Bumped whenever chunk_document's output can change for the same input. Stored
# on every note_embeddings row so the startup backfill can re-embed exactly the
# notes whose stored shape is stale — a version comparison instead of the table
# wipe migrations 0067/0077 had to do.
CHUNKER_VERSION = 1
# The public name of the space every score lives in, and the two facts that
# can invalidate a tuned number (#4104).
#
# EMBEDDING_MODEL is `_MODEL_NAME` under a name other modules may read. It was
# private until this step, which is precisely why nothing outside this file
# could state what space a threshold was measured in — a floor is a distance in
# THIS model's geometry and means nothing in another's.
#
# The pair is what a stamp is made of, and the pairing is the point: a score
# changes when the model changes (different geometry) OR when the document
# shape changes (different text embedded for the same record). Either one
# invalidates a number that was measured before it.
EMBEDDING_MODEL = _MODEL_NAME
def calibration_stamp() -> dict:
"""What a tuned retrieval number was measured against.
ONE definition, because the alternative is each reader assembling the pair
and one of them forgetting a half. Returned as a dict rather than a string
so a mismatch can say WHICH half moved — "the model changed" and "the
chunker changed" call for different responses, and a fused string can only
report that something did.
Deliberately says nothing about the CHAT model. A Claude upgrade changes no
score here and must never raise a recalibration prompt: a false alarm on
this surface teaches an operator to ignore the true one. `tests/
test_calibration_stamp.py` asserts that absence rather than trusting it.
"""
return {"embedding_model": EMBEDDING_MODEL, "shape_version": CHUNKER_VERSION}
# Character budget approximating the model window. Tokens-per-char varies by
# content — ~4 chars/token for prose, closer to 3 for code and tables — so 1400
# chars sits at roughly 350-470 tokens, leaving headroom for the title prefixed
# to every chunk. Deliberately conservative: our own measurement (#2485) says
# shorter, single-topic documents embed SHARPER, so the cost of over-splitting
# is a few extra cheap vectors while the cost of under-splitting is truncation —
# the exact data loss this exists to end.
_CHUNK_CHAR_BUDGET = 1400
_HEADING_RE = None # compiled lazily below to keep re import local
def _split_sections(body: str) -> list[str]:
"""Split a markdown body at heading lines, fence-aware.
Each section is a heading line plus everything under it; text before the
first heading is its own section. Heading-looking lines inside ``` / ~~~
code fences do not split — a commented `# step` in a recorded shell snippet
is content, not structure.
"""
import re
global _HEADING_RE
if _HEADING_RE is None:
_HEADING_RE = re.compile(r"^#{1,6}\s")
sections: list[list[str]] = [[]]
in_fence = False
for line in body.splitlines():
if line.lstrip().startswith(("```", "~~~")):
in_fence = not in_fence
if not in_fence and _HEADING_RE.match(line) and sections[-1]:
sections.append([line])
else:
sections[-1].append(line)
return ["\n".join(chunk).strip() for chunk in sections if any(s.strip() for s in chunk)]
def _split_paragraphs(section: str, budget: int) -> list[str]:
"""Break one oversize section into budget-sized pieces at paragraph
boundaries, hard-splitting only a single paragraph that alone exceeds the
budget (a monster table or code block — split at line boundaries so no
content is dropped, which is the entire point of this module)."""
pieces: list[str] = []
current = ""
for para in section.split("\n\n"):
while len(para) > budget:
# Hard split: prefer the last newline inside the budget so lines
# stay whole, then the last space so words do; a clean char cut is
# the final resort for one enormous unbroken token.
cut = para.rfind("\n", 0, budget)
if cut <= 0:
cut = para.rfind(" ", 0, budget)
if cut <= 0:
cut = budget
head, para = para[:cut], para[cut:].lstrip("\n ")
if current:
pieces.append(current)
current = ""
pieces.append(head.strip())
if not para.strip():
continue
candidate = f"{current}\n\n{para}" if current else para
if len(candidate) > budget and current:
pieces.append(current)
current = para
else:
current = candidate
if current:
pieces.append(current)
return pieces
def chunk_document(title: str | None, body: str | None) -> list[str]:
"""The document(s) a record is embedded AS — one string per chunk.
The contract every retrieval surface builds on:
- A record that fits the model window yields EXACTLY ONE chunk, identical
to the historical `title\\nbody` shape — snippets and reference notes,
the corpus's sharpest records, are byte-for-byte unaffected.
- A longer record is split at markdown heading boundaries (fence-aware),
small neighbouring sections merged, oversize sections split at paragraph
boundaries, so every chunk fits the window. NOTHING is dropped: every
line of the body lands in some chunk.
- Every chunk is prefixed with the record's title — each vector carries
its own topical anchor, the property that makes snippets discriminative
(#2485). Pieces sub-split from one section also repeat that section's
heading line, so "which part of which topic" survives the split.
- An empty record yields [] (callers gate on falsiness to skip embedding).
Bump CHUNKER_VERSION when changing anything observable here.
"""
single = embedding_text(title, body)
if not single:
return []
if len(single) <= _CHUNK_CHAR_BUDGET:
return [single]
title = title or ""
# Budget for section content, net of the title prefix added to every chunk.
budget = max(200, _CHUNK_CHAR_BUDGET - len(title) - 1)
# Merge small adjacent sections upward so tiny sections don't each spend a
# vector, then split anything still over budget at paragraph boundaries.
merged: list[str] = []
for section in _split_sections(body or ""):
if merged and len(merged[-1]) + 2 + len(section) <= budget:
merged[-1] = f"{merged[-1]}\n\n{section}"
else:
merged.append(section)
chunks: list[str] = []
for section in merged:
if len(section) <= budget:
chunks.append(embedding_text(title, section))
continue
pieces = _split_paragraphs(section, budget)
first_line = section.split("\n", 1)[0]
heading = first_line if first_line.lstrip().startswith("#") else ""
for i, piece in enumerate(pieces):
# Repeat the section heading on continuation pieces so each vector
# still knows what topic it is part of.
if i > 0 and heading and not piece.startswith(heading):
piece = f"{heading}\n{piece}"
chunks.append(embedding_text(title, piece))
return chunks
async def _claim_parent_row(session, id_column, row_id: int, label: str) -> bool:
"""Lock the record a vector belongs to BEFORE rewriting that vector (#3262).
An embedding write and a cascading delete of the same record take the same
two row locks in OPPOSITE orders. The embedder deletes the old chunk rows
and then, on INSERT, needs the foreign key's lock on the parent; a delete
of the parent — or of the rulebook, topic or project above it — locks the
parent first and cascades down into the chunk rows. That is a cycle, and
Postgres breaks it by killing one side at random: sometimes the embedding
write, which is swallowed and invisible, and sometimes the operator's
delete, which surfaces as a 500 on an operation that should have worked.
Claiming the parent first REMOVES the cycle rather than narrowing it.
Either the embedder arrives first and the delete waits its turn behind it,
or the delete already holds the row and NOWAIT makes the embedder lose at
once. The embedder is the side that should lose: a skipped refresh costs a
stale vector until the next write or the startup backfill, and the other
outcome costs a person their request.
FOR KEY SHARE, not FOR UPDATE — it is precisely the lock the INSERT's
foreign key would take anyway, so it conflicts with a delete of the parent
and with nothing else. An ordinary edit of the same record, or a second
refresh racing this one, is unaffected.
Returns False when the row is locked or already gone; the caller skips.
"""
try:
held = (await session.execute(
select(id_column)
.where(id_column == row_id)
# BOTH flags: SQLAlchemy spells the four Postgres row locks as a
# read/key_share pair, and key_share alone is FOR NO KEY UPDATE —
# which would make two refreshes of one record fight each other.
.with_for_update(read=True, key_share=True, nowait=True)
)).scalar_one_or_none()
except Exception:
# LockNotAvailable: this record is being deleted right now. Not an
# error — the delete wins by design.
logger.debug("Skipping embedding for %s %d — row is being deleted", label, row_id)
return False
if held is None:
logger.debug("Skipping embedding for %s %d — row is gone", label, row_id)
return False
return True
async def upsert_note_embedding(
note_id: int, user_id: int, title: str | None, body: str | None
) -> None:
"""Chunk, embed and persist a note's vectors. Safe to fire-and-forget.
Takes title/body rather than pre-built text so the chunking happens HERE —
one path for the write path, the recurrence spawn and the startup backfill,
which is the same single-definition discipline embedding_text existed for.
Replacement is atomic per note: old rows are deleted and the new chunk set
inserted in one transaction, so a concurrent read sees the old shape or the
new one, never a mixture.
"""
chunks = chunk_document(title, body)
try:
if not chunks:
# A record emptied of content should stop being findable by its
# old content — clear stale vectors rather than leaving them.
async with async_session() as session:
await session.execute(
delete(NoteEmbedding).where(NoteEmbedding.note_id == note_id)
)
await session.commit()
return
except Exception:
logger.warning("Failed to clear embedding for note %d", note_id, exc_info=True)
return
try:
vectors = await get_embeddings(chunks)
except Exception:
logger.debug("Skipping embedding for note %d — embedder unavailable", note_id)
return
try:
async with async_session() as session:
if not await _claim_parent_row(session, Note.id, note_id, "note"):
return
await session.execute(
delete(NoteEmbedding).where(NoteEmbedding.note_id == note_id)
)
for index, (chunk, vector) in enumerate(zip(chunks, vectors)):
session.add(
NoteEmbedding(
note_id=note_id,
chunk_index=index,
user_id=user_id,
embedding=vector,
chunk_text=chunk,
chunker_version=CHUNKER_VERSION,
)
)
await session.commit()
logger.debug("Upserted %d chunk embedding(s) for note %d", len(chunks), note_id)
except Exception:
logger.warning("Failed to persist embedding for note %d", note_id, exc_info=True)
# Kinds that belong to no single project, and are therefore reachable from a
# project-scoped search of a DIFFERENT project when a caller asks for them
# (milestone 385 step 3).
#
# A lesson is the whole reason this exists. "A better way to think about this
# problem" is not true only where it was learned, and a lesson confined to its
# origin project would be unreachable exactly where it is most useful — on the
# next project, which is the case the kind was created for (#3727).
# `semantic_search_rules` has always had this property: it scopes by OWNERSHIP
# rather than by what binds a given project, because "is there a rule about
# this" is a question asked across a whole rulebook. A lesson asks the same
# kind of question.
#
# Spelled as a literal rather than imported from `services.lessons`, which
# imports `trigger_title` from this module and would close a cycle. A guard
# pins the two equal instead.
GLOBAL_NOTE_TYPES: tuple[str, ...] = ("lesson",)
# Both searches rank WITHOUT the threshold and apply it in Python, so the best
# rejected score stays observable (#3670). The qualifying set is provably
# unchanged: rows arrive ordered by distance ascending, so every above-bar row
# sorts ahead of every below-bar one, and an over-fetch that used to return N
# above-bar rows returns the same N plus some losers. What changes is only that
# the losers are now visible instead of discarded inside the query.
#
# That visibility is the entire point. A bar can only be judged from the calls
# it TURNED AWAY — a 0.72 bar rejecting a stream of 0.71s is set too high by a
# hair, one rejecting 0.30s is working — and those two are indistinguishable
# from any arrangement of the columns that survive the filter.
#
# `report` is how the score gets out without changing what a search RETURNS.
# Eight of the eleven call sites want hits and nothing else; the three that
# write telemetry pass a dict and read `best_available_score` back out of it.
def record_best_chunk(report: dict | None, chunks: dict[int, dict]) -> None:
"""Publish the winning chunk per record into `report["best_chunk"]`.
Every semantic search here collapses several chunk rows to the best one per
record, which means each of them KNOWS which passage earned the hit — and
each of them used to drop it, leaving every caller to preview the head of
the document instead. The head is a different span, one the search has
already scored lower, and nothing in the result said so (#4243).
It rides in `report` rather than in the return value because all three
searches return `list[tuple[float, Record]]` and roughly thirty sites
unpack that pair; widening it would be an interface change to every one of
them with nothing to catch a miss (lesson #4207). `report` is already the
side-channel these functions use for `searched` and `best_available_score`,
so this adds a key to a channel callers already open.
Shape: {record_id: {"index": int, "text": str}}. A caller that passed no
report simply doesn't get it, and every consumer falls back to the body.
"""
if report is None:
return
report["best_chunk"] = chunks
async def semantic_search_notes(
user_id: int,
query: str,
exclude_ids: set[int] | None = None,
limit: int = 8,
threshold: float = _SIMILARITY_THRESHOLD,
project_id: int | None = None,
is_task: bool | None = None,
note_type: str | Sequence[str] | None = None,
task_kind: str | Sequence[str] | None = None,
orphan_only: bool = False,
include_global_kinds: bool = False,
scope: str = "own",
demote_superseded: bool = True,
system_id: int | None = None,
report: dict | None = None,
) -> list[tuple[float, Note]]:
"""Return up to *limit* (score, note) pairs most relevant to *query*.
Scores are cosine similarities in [-1, 1]; only notes at or above
*threshold* are returned, sorted highest-first.
Pass `report` (an empty dict) to learn what the threshold turned away:
the function sets `report["best_available_score"]` to the highest score
anything reached, or None when the corpus offered nothing at all. It is
the only figure that survives a call returning nothing, and therefore the
only one a bar can be judged from (#3670).
It also sets `report["searched"]`: False before anything can return, True
only where a real result set exists. So an empty query, an unavailable
embedder and a failed database query all leave it FALSE, and a caller can
tell a search that found nothing from one that never ran. A caller logging
telemetry must check it — recording a failed search as a zero-result call
reports a decline the ranker never made (#3765). ABSENT means no search
touched the dict at all, which is a stand-in in a test, not a real call.
`note_type` narrows to a record kind, or several (e.g. "snippet", or
("snippet", "note")), for callers that want prior art rather than everything
embedded.
`task_kind` restricts TASKS to the given kinds while leaving non-task notes
untouched. That asymmetry is the point: "recorded experience" is issues plus
dev-logs, and those differ on `is_task`, so neither `note_type` nor `is_task`
alone can express it. With `note_type="note", task_kind="issue"` a caller
gets fixed problems and durable notes without the open to-do list.
`include_global_kinds` lets a project-scoped search ALSO reach the kinds in
GLOBAL_NOTE_TYPES — records that belong to no single project — so a lesson
written on one project is found from another. It widens the PROJECT filter
only: a caller that also passes `note_type` still gets exactly the kinds it
asked for, so narrowing to snippets does not quietly acquire lessons.
Off by default, because two callers depend on the project filter holding.
The near-duplicate gate compares a record only against its own project on
purpose, and a globally-visible kind would let a lesson block an unrelated
note's create on a project its author never touched. Ordinary note recall
is project-scoped for the same reason — the point of the carve-out is that
ONE kind escapes, not that scoping is weaker.
`scope` ("own" | "browse" | "read", see access.notes_visibility_clause)
decides how far this may see. It exists because this one function serves
three different kinds of act: an explicit search, which should reach
everything the caller may read; passive auto-injection, which must not pull
an unrequested record into their context; and the near-duplicate gate, whose
verdict must not depend on other people's notes at all. Defaults to "own" so
a caller that forgets is wrong in the safe direction.
Ranking and the top-k cut happen in Postgres via pgvector's cosine-distance
operator (`<=>`, exposed as ``Vector.cosine_distance``) backed by the HNSW
index from migration 0067 — so this is an indexed ``ORDER BY ... LIMIT k``
rather than a full-table scan. Cosine distance is ``1 - cosine_similarity``,
so a similarity floor of *threshold* is a distance ceiling of
``1 - threshold`` and similarity is recovered as ``1 - distance``.
`demote_superseded` applies the supersession penalty (#278): a record a
later note claims to have overtaken ranks below its equals. Callers asking
"what is the current answer" want it; the near-duplicate gate does NOT, and
passes False — a superseded record is still a duplicate of what you are
about to write, and demoting it there would let the same note be recorded
twice, the second time invisibly.
Returns an empty list if the embedder is unavailable or on any error.
"""
# Stamped FALSE before anything can return, flipped True only where a real
# result set exists (#3765). Every early return below leaves it false, so a
# caller can tell a search that found nothing from one that never ran. It
# has to be the first thing done to `report`: a return added above this
# line would leave the key ABSENT, which reads as "no caller asked".
if report is not None:
report["searched"] = False
if not query or not query.strip():
return []
try:
query_vec = await get_embedding(query)
except Exception:
logger.debug("Semantic search skipped — embedder unavailable")
return []
# Distance ceiling equivalent to the similarity floor. Clamp to the valid
# cosine-distance range [0, 2] so a threshold of, say, -1 doesn't produce a
# nonsensical ceiling.
distance = NoteEmbedding.embedding.cosine_distance(query_vec)
try:
async with async_session() as session:
# Scope on Note, not NoteEmbedding.user_id: the embedding row belongs
# to the note's owner, so filtering it would pin every scope to "own"
# and leave shared records unreachable by meaning.
stmt = (
# chunk_index/chunk_text ride along so the collapse below can
# say WHICH passage matched. Without them the caller is left
# previewing the head of the body — a span this query has
# already determined is not why the record ranked (#4243).
select(
Note,
distance.label("distance"),
NoteEmbedding.chunk_index,
NoteEmbedding.chunk_text,
)
.select_from(NoteEmbedding)
.join(Note, NoteEmbedding.note_id == Note.id)
.where(
notes_visibility_clause(user_id, scope),
Note.deleted_at.is_(None),
)
)
if orphan_only:
stmt = stmt.where(Note.project_id.is_(None))
elif project_id is not None:
in_project = Note.project_id == project_id
if include_global_kinds:
in_project = or_(
in_project, Note.note_type.in_(GLOBAL_NOTE_TYPES)
)
stmt = stmt.where(in_project)
# Narrow to records tagged to one System (subsystem/area). An
# association filter, not a ranking signal — membership in the
# candidate set, decided before scoring, like project_id above.
if system_id is not None:
from scribe.models.system import RecordSystem
stmt = stmt.where(
select(RecordSystem.id)
.where(
RecordSystem.note_id == Note.id,
RecordSystem.system_id == system_id,
)
.exists()
)
if is_task is True:
stmt = stmt.where(Note.status.isnot(None))
elif is_task is False:
stmt = stmt.where(Note.status.is_(None))
# Narrow to one kind of record, or several. Composes with is_task
# rather than replacing it — 'snippet' is a non-task note_type, so a
# caller asking for prior art gets snippets and not the dev-log that
# mentions them.
if note_type:
kinds = [note_type] if isinstance(note_type, str) else list(note_type)
stmt = stmt.where(Note.note_type.in_(kinds))
# Restrict TASKS to certain kinds while leaving notes alone. A note
# has no task_kind that means anything, so a plain `.in_()` would
# drop every dev-log — which is exactly the record a caller asking
# for prior experience wants most.
if task_kind:
tkinds = [task_kind] if isinstance(task_kind, str) else list(task_kind)
stmt = stmt.where(
or_(Note.status.is_(None), Note.task_kind.in_(tkinds))
)
if exclude_ids:
stmt = stmt.where(NoteEmbedding.note_id.notin_(exclude_ids))
# OVER-FETCH when a re-rank follows, so the demotion can actually
# move something. Demoting after a LIMIT k would be theatre: the cut
# already happened, so a superseded record pushed down still sits in
# the results and the live record that should have replaced it was
# never fetched.
#
# Ordering stays on RAW distance so pgvector's HNSW index still
# serves it (migration 0067). Ordering by `distance + penalty`
# instead would be exact, and would turn an indexed top-k into a
# scan-and-sort of every embedded note.
#
# The cost of that trade, stated plainly: a live record outside the
# over-fetch window cannot be promoted into the results. With a
# penalty far smaller than the window's score spread, that case
# needs the true answer to be more than _SUPERSESSION_OVERFETCH
# ranks down, which no observed query comes close to.
fetch = limit * _CHUNK_OVERFETCH * (
_SUPERSESSION_OVERFETCH if demote_superseded else 1
)
# NO threshold predicate — see the note above this function. The
# bar is applied after the collapse, where the rejected scores can
# still be seen.
stmt = stmt.order_by(distance.asc()).limit(fetch)
rows = list((await session.execute(stmt)).all())
except Exception:
logger.warning("Failed to query note embeddings", exc_info=True)
return []
# Collapse chunk rows to BEST-CHUNK-PER-NOTE (#280): rows arrive ordered by
# distance, so the first appearance of a note is its best chunk and later
# appearances are the same note matched less well. A note's relevance IS
# its best section's relevance — a query about one topic of a long record
# must find that record as strongly as if the topic were the whole record.
# Recover similarity (1 - distance); order stays highest-first.
scored: list[tuple[float, Note]] = []
seen: set[int] = set()
# The winning row IS the best chunk, by the ordering above — so this is the
# one place that knows which passage earned the hit. Kept beside the score
# rather than returned with it: the return type is list[tuple[float, Note]]
# and ten callers unpack it at ~18 sites, so widening the tuple would be an
# interface change to every one of them with nothing to catch the misses
# (lesson #4207). `report` is the side-channel this function already uses
# for best_available_score.
best_chunk: dict[int, dict] = {}
for note, dist, chunk_index, chunk_text in rows:
if int(note.id) in seen:
continue
seen.add(int(note.id))
scored.append((1.0 - float(dist), note))
best_chunk[int(note.id)] = {
"index": int(chunk_index),
"text": chunk_text or "",
}
# The best score anything reached, bar or no bar. Recorded BEFORE the
# filter because a call that returns nothing is exactly when it matters.
if report is not None:
# `searched` is what stops a null score meaning four things (#3765).
# Every early return above — empty query, embedder down, and the broad
# `except` around the query itself — leaves this key ABSENT, so a
# caller can tell "I looked and there was nothing" from "I never
# looked" and from "the query failed". Set here, at the one point past
# which a real result set exists.
report["searched"] = True
# ONE unpack, so the score and the id cannot describe different records
# (#3807). Splitting these into two expressions is how a later edit
# pairs a score with its neighbour's id.
best = scored[0] if scored else None
report["best_available_score"] = best[0] if best else None
report["best_available_id"] = int(best[1].id) if best else None
scored = [pair for pair in scored if pair[0] >= threshold]
if not demote_superseded:
final = scored[:limit]
else:
final = await _apply_supersession_penalty(scored, limit)
# Only for what actually came back, so a caller can key straight off the
# results without carrying chunks for records it never saw.
record_best_chunk(report, {
int(n.id): best_chunk[int(n.id)]
for _s, n in final
if int(n.id) in best_chunk
})
return final
async def backfill_note_embeddings() -> None:
"""(Re-)embed every note that is missing vectors OR whose stored vectors
were produced by an older chunker.
Runs as a background task at startup. Version-awareness is what makes a
document-shape change deployable: migration 0077 cleared the table once,
and every later CHUNKER_VERSION bump re-embeds the stale notes here — a
version comparison instead of another wipe. Adds a small sleep between
notes so a large backfill doesn't peg CPU.
"""
try:
async with async_session() as session:
current = {
row[0]
for row in (
await session.execute(
select(NoteEmbedding.note_id).where(
NoteEmbedding.chunker_version == CHUNKER_VERSION
)
)
).fetchall()
}
result = await session.execute(
select(Note.id, Note.user_id, Note.title, Note.body)
)
notes_to_embed = [
row for row in result.fetchall() if row[0] not in current
]
except Exception:
logger.warning("Embedding backfill: failed to query notes", exc_info=True)
return
if not notes_to_embed:
logger.info("Embedding backfill: all notes current at chunker v%d", CHUNKER_VERSION)
return
logger.info(
"Embedding backfill: embedding %d notes at chunker v%d",
len(notes_to_embed), CHUNKER_VERSION,
)
success = 0
for note_id, user_id, title, body in notes_to_embed:
if not chunk_document(title, body):
continue
await upsert_note_embedding(note_id, user_id, title, body)
success += 1
await asyncio.sleep(0.05) # gentle pacing
logger.info("Embedding backfill complete: %d/%d notes embedded", success, len(notes_to_embed))
# ── Rules (milestone 307, note 3026) ────────────────────────────────────
def rule_document(
title: str | None, statement: str | None, when_to_apply: str | None,
) -> tuple[str | None, str | None]:
"""The (title, body) a rule is EMBEDDED as — trigger first, `why` never.
Both halves of this are measured, not guessed (note 2485). That pass found
the snippet was the only sharp record in the corpus — a 0.153 top-to-second
gap against 0.0100.023 for everything else — and that the cause was its
SHAPE: `{name}{when_to_use}` as the title and `**When to use:** …`
repeated in the body, so purpose appears twice in a short document and
dominates the vector. This mirrors that exactly.
And it excludes `why` on the same evidence. `why` is dated incident
narrative — rule 46's runs to 4,300 characters of it — and long,
multi-topic prose is precisely what made sixteen dev-logs mutually
indistinguishable: the average lands on the centroid of "development",
which every one of them shares. Adding `why` would not give the vector more
to work with; it would give every rule the same thing to work with.
A rule with no trigger yet degrades to title + statement. It still embeds,
just less sharply — which is an argument for backfilling triggers, not an
argument for padding the document with whatever text is lying around.
"""
trigger = (when_to_apply or "").strip()
name = (title or "").strip()
body = (statement or "").strip()
if not trigger:
return name or None, body or None
return (
trigger_title(name, trigger),
f"When to apply: {trigger}\n\n{body}" if body else f"When to apply: {trigger}",
)
async def upsert_rule_embedding(
rule_id: int, title: str | None, statement: str | None,
when_to_apply: str | None = None,
) -> None:
"""Chunk, embed and persist a rule's vectors. Safe to fire-and-forget.
The note twin's contract, for the same reasons: the document is built HERE
so the write path, the backfill and any re-embed share one definition, and
replacement is atomic per rule so a concurrent read sees the old chunk set
or the new one, never a mixture.
"""
from scribe.models.rulebook import Rule # runtime import: see TYPE_CHECKING above
doc_title, doc_body = rule_document(title, statement, when_to_apply)
chunks = chunk_document(doc_title, doc_body)
try:
if not chunks:
async with async_session() as session:
await session.execute(
delete(RuleEmbedding).where(RuleEmbedding.rule_id == rule_id)
)
await session.commit()
return
except Exception:
logger.warning("Failed to clear embedding for rule %d", rule_id, exc_info=True)
return
try:
vectors = await get_embeddings(chunks)
except Exception:
logger.debug("Skipping embedding for rule %d — embedder unavailable", rule_id)
return
try:
async with async_session() as session:
if not await _claim_parent_row(session, Rule.id, rule_id, "rule"):
return
await session.execute(
delete(RuleEmbedding).where(RuleEmbedding.rule_id == rule_id)
)
for index, (chunk, vector) in enumerate(zip(chunks, vectors)):
session.add(
RuleEmbedding(
rule_id=rule_id,
chunk_index=index,
embedding=vector,
chunk_text=chunk,
chunker_version=CHUNKER_VERSION,
)
)
await session.commit()
except Exception:
logger.warning("Failed to persist embedding for rule %d", rule_id, exc_info=True)
async def semantic_search_rules(
user_id: int,
query: str,
limit: int = 5,
threshold: float = _SIMILARITY_THRESHOLD,
kind: str | None = None,
report: dict | None = None,
*,
project_id: int | None = None,
everywhere: bool = False,
) -> list[tuple[float, "Rule"]]:
"""Return up to *limit* (score, rule) pairs most relevant to *query*.
Pass `report` (an empty dict) to learn what the threshold turned away:
the function sets `report["best_available_score"]` to the highest score
anything reached, or None when the corpus offered nothing at all. It is
the only figure that survives a call returning nothing, and therefore the
only one a bar can be judged from (#3670).
It also sets `report["searched"]`: False before anything can return, True
only where a real result set exists. So an empty query, an unavailable
embedder and a failed database query all leave it FALSE, and a caller can
tell a search that found nothing from one that never ran. A caller logging
telemetry must check it — recording a failed search as a zero-result call
reports a decline the ranker never made (#3765). ABSENT means no search
touched the dict at all, which is a stand-in in a test, not a real call.
SCOPED, and the scope is a rule's home (milestone 414). A rule lives in a
rulebook topic — GLOBAL, it applies wherever its owner works — or on one
project, where it applies to that project and nowhere else:
- default (`project_id=None`): global rules only. A hook with no bound
project gets these, and so does any caller that forgets to say; the
safe failure is surfacing less, not another project's rules.
- `project_id=N`: global rules plus project N's own, and N's only when
the caller can read that project (access.can_read_project, so a shared
project's rules reach its collaborators too).
- `everywhere=True`: every rule the caller owns, in any home. Only for an
explicit whole-rulebook question — `search(content_type="rule")` with no
project — where "is there a rule about this" is asked across everything.
This used to be scoped by OWNERSHIP alone, on the argument that "is there
a rule about this" wants the whole rulebook. That is still right for the
explicit ask. It was wrong for the hooks, which inject unasked: every
project's rules surfaced in every other project's sessions — one repo's
template conventions arriving while editing an unrelated one — and a
project rule meant nothing a session could feel.
THERE IS NO TIER TO NARROW BY ANY MORE (milestone 394). This carried a
`tier` parameter, and the arms deliberately passed nothing: filtering on it
made a whole class of rules permanently ineligible for the one mechanism
that surfaces a rule AT the moment it applies. The tier is now gone
entirely, so every rule is eligible for every arm and relevance is the
threshold's job alone — see the block above RULEHINT_LIMIT in
services/plugin_context.py for what those scores are read against.
`kind` narrows to `rule` or `preference`, and NONE is likewise the ordinary
case: a caller asking "what governs this" wants both, because the reader
needs to know what binds AND how the operator wants it done. The one place
it is passed is a RESERVED SLOT — a query that may only return a
preference, so the slot cannot be spent on something else. That is the
same reason `note_type` exists on the sibling search, and the same failure
it prevents: a slot silently filled by the wrong kind is worse than no
slot, because the line is indistinguishable from one that earned its place
on score.
Collapses to best-chunk-per-rule like the note search, so a long rule split
across chunks competes once rather than crowding the results with itself.
Returns an empty list if the embedder is unavailable or on any error.
"""
from scribe.models.project import Project
from scribe.models.rulebook import Rule, Rulebook, RulebookTopic
# See the sibling search: stamped before anything can return (#3765).
if report is not None:
report["searched"] = False
if not query or not query.strip():
return []
try:
query_vec = await get_embedding(query)
except Exception:
logger.debug("Rule search skipped — embedder unavailable")
return []
distance = RuleEmbedding.embedding.cosine_distance(query_vec)
try:
# topic_id XOR project_id (migration 0059), so a rule matches exactly
# one arm of whichever clause applies. Inside the try: the access
# check reads the database too, and this function fails open.
global_rule = Rulebook.owner_user_id == user_id
if everywhere:
home = or_(global_rule, Project.user_id == user_id)
elif project_id and await can_read_project(user_id, project_id):
home = or_(global_rule, Rule.project_id == project_id)
else:
home = global_rule
async with async_session() as session:
rows = (await session.execute(
select(
Rule,
distance.label("distance"),
RuleEmbedding.chunk_index,
RuleEmbedding.chunk_text,
)
.select_from(RuleEmbedding)
.join(Rule, RuleEmbedding.rule_id == Rule.id)
.outerjoin(RulebookTopic, Rule.topic_id == RulebookTopic.id)
.outerjoin(Rulebook, RulebookTopic.rulebook_id == Rulebook.id)
.outerjoin(Project, Rule.project_id == Project.id)
.where(
Rule.deleted_at.is_(None),
# No threshold predicate — see the note above
# semantic_search_notes. Applied below, after the collapse.
home,
*( [Rule.kind == kind] if kind else [] ),
)
# Overfetch so collapsing chunks to their best row still fills
# the page — the same reason the note search overfetches.
.order_by(distance)
.limit(limit * _CHUNK_OVERFETCH)
)).all()
except Exception:
logger.warning("Rule semantic search failed", exc_info=True)
return []
best: dict[int, tuple[float, object]] = {}
# Which chunk won, kept beside the score it won with — a rule's `why` and
# `how_to_apply` are long, and a caller shown only the head cannot see the
# clause that actually matched (#4243).
won: dict[int, dict] = {}
for rule, dist, chunk_index, chunk_text in rows:
score = 1.0 - float(dist)
if rule.id not in best or score > best[rule.id][0]:
best[rule.id] = (score, rule)
won[int(rule.id)] = {
"index": int(chunk_index), "text": chunk_text or "",
}
ranked = sorted(best.values(), key=lambda pair: pair[0], reverse=True)
kept = [pair for pair in ranked if pair[0] >= threshold][:limit]
record_best_chunk(report, {
int(r.id): won[int(r.id)] for _s, r in kept if int(r.id) in won
})
if report is not None:
# See the sibling search: absent means the search never ran (#3765).
report["searched"] = True
# One unpack — see the sibling search (#3807).
best = ranked[0] if ranked else None
report["best_available_score"] = best[0] if best else None
report["best_available_id"] = int(best[1].id) if best else None
return kept
async def backfill_rule_embeddings() -> None:
"""Embed rules that have no current vectors. Runs at startup beside the
note backfill; a CHUNKER_VERSION bump re-embeds rather than wiping."""
from scribe.models.rulebook import Rule
try:
async with async_session() as session:
current = select(RuleEmbedding.rule_id).where(
RuleEmbedding.chunker_version == CHUNKER_VERSION
)
stale = (await session.execute(
select(Rule.id, Rule.title, Rule.statement, Rule.when_to_apply)
.where(Rule.deleted_at.is_(None), Rule.id.notin_(current))
)).all()
except Exception:
logger.warning("Rule embedding backfill: failed to query rules", exc_info=True)
return
if not stale:
logger.info("Rule embedding backfill: all rules current at chunker v%d", CHUNKER_VERSION)
return
logger.info("Rule embedding backfill: embedding %d rule(s)", len(stale))
for rule_id, title, statement, when_to_apply in stale:
await upsert_rule_embedding(rule_id, title, statement, when_to_apply)
# ── Milestones (milestone 415) ──────────────────────────────────────────
def milestone_document(
title: str | None, description: str | None, body: str | None,
) -> tuple[str | None, str | None]:
"""The (title, body) a milestone is EMBEDDED as.
Title and one-line description lead, the way a snippet's name and purpose
lead its document (note 2485): the question this search answers is "does
a plan for this already exist?", and a plan is recognised by what it is
FOR. The plan body follows, chunked, so a milestone whose description is
empty — most roadmap milestones written by hand — is still findable by the
words of its design.
"""
name = (title or "").strip()
purpose = (description or "").strip()
plan = (body or "").strip()
doc_title = f"{name}{purpose}" if name and purpose else (name or purpose or None)
parts = [p for p in (purpose, plan) if p]
return doc_title, "\n\n".join(parts) or None
async def upsert_milestone_embedding(
milestone_id: int, title: str | None, description: str | None, body: str | None,
) -> None:
"""Chunk, embed and persist a milestone's vectors. Safe to fire-and-forget.
The rule twin's contract: one document definition shared by the write path
and the backfill, and an atomic per-milestone replacement guarded by the
parent-row claim (#3262), so a milestone deleted mid-refresh wins.
"""
from scribe.models.embedding import MilestoneEmbedding
from scribe.models.milestone import Milestone
doc_title, doc_body = milestone_document(title, description, body)
chunks = chunk_document(doc_title, doc_body)
try:
if not chunks:
async with async_session() as session:
await session.execute(
delete(MilestoneEmbedding).where(MilestoneEmbedding.milestone_id == milestone_id)
)
await session.commit()
return
except Exception:
logger.warning("Failed to clear embedding for milestone %d", milestone_id, exc_info=True)
return
try:
vectors = await get_embeddings(chunks)
except Exception:
logger.debug("Skipping embedding for milestone %d — embedder unavailable", milestone_id)
return
try:
async with async_session() as session:
if not await _claim_parent_row(session, Milestone.id, milestone_id, "milestone"):
return
await session.execute(
delete(MilestoneEmbedding).where(MilestoneEmbedding.milestone_id == milestone_id)
)
for index, (chunk, vector) in enumerate(zip(chunks, vectors)):
session.add(MilestoneEmbedding(
milestone_id=milestone_id, chunk_index=index, embedding=vector,
chunk_text=chunk, chunker_version=CHUNKER_VERSION,
))
await session.commit()
except Exception:
logger.warning("Failed to persist embedding for milestone %d", milestone_id, exc_info=True)
async def semantic_search_milestones(
user_id: int,
query: str,
*,
project_id: int | None = None,
status: str | None = None,
limit: int = 5,
threshold: float = _SIMILARITY_THRESHOLD,
report: dict | None = None,
) -> list[tuple[float, "Milestone"]]:
"""Return up to *limit* (score, milestone) pairs most like *query*.
Answers "is there already a plan for this?" — the question a session asks
before start_planning, and the one the planning gate asks for it.
SCOPE. With `project_id`, that project's milestones, provided the caller
can read the project (access.can_read_project, rule 78) — a collaborator on
a shared project sees its plans. Without one, the milestones the caller
owns across their projects. `status` narrows to "active" or "done".
Collapses to best-chunk-per-milestone, like the sibling searches. Returns
an empty list if the embedder is unavailable, the project is not readable,
or on any error: a recall aid must never break the call it serves.
"""
from scribe.models.embedding import MilestoneEmbedding
from scribe.models.milestone import Milestone
if not query or not query.strip():
return []
try:
query_vec = await get_embedding(query)
except Exception:
logger.debug("Milestone search skipped — embedder unavailable")
return []
distance = MilestoneEmbedding.embedding.cosine_distance(query_vec)
try:
if project_id:
if not await can_read_project(user_id, project_id):
return []
scope = Milestone.project_id == project_id
else:
scope = Milestone.user_id == user_id
async with async_session() as session:
rows = (await session.execute(
select(
Milestone,
distance.label("distance"),
MilestoneEmbedding.chunk_index,
MilestoneEmbedding.chunk_text,
)
.select_from(MilestoneEmbedding)
.join(Milestone, MilestoneEmbedding.milestone_id == Milestone.id)
.where(
scope,
Milestone.deleted_at.is_(None),
*([Milestone.status == status] if status else []),
)
.order_by(distance)
.limit(limit * _CHUNK_OVERFETCH)
)).all()
except Exception:
logger.warning("Milestone semantic search failed", exc_info=True)
return []
best: dict[int, tuple[float, object]] = {}
# A milestone's `body` IS the plan, and search results show its short
# `description` — so a match on the design was previewed by a sentence that
# need not mention it. The winning chunk is what the caller should see.
won: dict[int, dict] = {}
for milestone, dist, chunk_index, chunk_text in rows:
score = 1.0 - float(dist)
if milestone.id not in best or score > best[milestone.id][0]:
best[milestone.id] = (score, milestone)
won[int(milestone.id)] = {
"index": int(chunk_index), "text": chunk_text or "",
}
ranked = sorted(best.values(), key=lambda pair: pair[0], reverse=True)
kept = [pair for pair in ranked if pair[0] >= threshold][:limit]
record_best_chunk(report, {
int(m.id): won[int(m.id)] for _s, m in kept if int(m.id) in won
})
return kept
async def backfill_milestone_embeddings() -> None:
"""Embed milestones that have no current vectors. Runs at startup beside
the note and rule backfills; a CHUNKER_VERSION bump re-embeds."""
from scribe.models.embedding import MilestoneEmbedding
from scribe.models.milestone import Milestone
try:
async with async_session() as session:
current = select(MilestoneEmbedding.milestone_id).where(
MilestoneEmbedding.chunker_version == CHUNKER_VERSION
)
stale = (await session.execute(
select(Milestone.id, Milestone.title, Milestone.description, Milestone.body)
.where(Milestone.deleted_at.is_(None), Milestone.id.notin_(current))
)).all()
except Exception:
logger.warning("Milestone embedding backfill: failed to query milestones", exc_info=True)
return
if not stale:
logger.info("Milestone embedding backfill: all milestones current at chunker v%d", CHUNKER_VERSION)
return
logger.info("Milestone embedding backfill: embedding %d milestone(s)", len(stale))
for milestone_id, title, description, body in stale:
await upsert_milestone_embedding(milestone_id, title, description, body)