Files
MobilityOps/backend/app/services/knowledge/demo.py
T
NuklearRabbit b511ba2dbc M5: implement RAGcore knowledge integration
KnowledgeProvider protocol with a deterministic TF-IDF-weighted extractive demo provider (never generative, always cites real excerpts) and a RAGcore HTTP adapter that degrades cleanly to unavailable. Knowledge nav + chat-style Q&A UI with source cards and honest grounded/insufficient/unavailable states. 57 backend tests passing, ruff clean. Fixed a real relevance bug (generic terms like "vehicle" crowding out distinctive matches) via IDF weighting, found by testing the actual S6 scenario. Verified end-to-end in the browser: grounded damage question cites both expected procedures; unrelated question honestly returns insufficient evidence with no fabrication.
2026-08-01 22:57:06 +02:00

222 lines
7.6 KiB
Python

from __future__ import annotations
import math
import re
from dataclasses import dataclass, field
from pathlib import Path
from app.core.config import get_settings
from app.services.knowledge import GroundedAnswer, KnowledgeHealth, SourceCard
STOPWORDS = {
"a", "an", "the", "is", "are", "was", "were", "be", "been", "being",
"to", "of", "in", "on", "at", "for", "and", "or", "but", "if", "then",
"do", "does", "did", "must", "may", "can", "could", "should", "would",
"i", "you", "it", "we", "they", "my", "your", "what", "when", "how",
"with", "without", "this", "that", "these", "those", "not", "no",
}
_WORD_RE = re.compile(r"[a-z0-9]+")
def _stem(word: str) -> str:
# Deterministic, intentionally crude suffix stripping — good enough to match "returns"
# with "return" or "damaged" with "damage" without pulling in a stemming dependency.
for suffix in ("ing", "edly", "ed", "es", "s"):
if len(word) > len(suffix) + 2 and word.endswith(suffix):
return word[: -len(suffix)]
return word
def _tokenize(text: str) -> set[str]:
words = _WORD_RE.findall(text.lower())
return {_stem(w) for w in words if w not in STOPWORDS and len(w) > 2}
@dataclass
class Document:
document_id: str
title: str
version: str
title_tokens: set[str] = field(default_factory=set)
@dataclass
class ScoredSection:
document: Document
heading: str
text: str
heading_tokens: set[str]
body_tokens: set[str]
def _parse_frontmatter(raw: str) -> tuple[dict[str, str], str]:
if not raw.startswith("---"):
return {}, raw
end = raw.find("\n---", 3)
if end == -1:
return {}, raw
block = raw[3:end].strip()
body = raw[end + 4 :].lstrip("\n")
meta: dict[str, str] = {}
for line in block.splitlines():
if ":" not in line:
continue
key, _, value = line.partition(":")
meta[key.strip()] = value.strip().strip('"')
return meta, body
def _split_sections(body: str) -> list[tuple[str, str]]:
sections: list[tuple[str, str]] = []
current_heading = "Overview"
current_lines: list[str] = []
for line in body.splitlines():
if line.startswith("## "):
if current_lines:
sections.append((current_heading, "\n".join(current_lines).strip()))
current_heading = line[3:].strip()
current_lines = []
elif line.startswith("# "):
continue
else:
current_lines.append(line)
if current_lines:
sections.append((current_heading, "\n".join(current_lines).strip()))
return sections
def _load_sections(procedures_dir: Path) -> list[ScoredSection]:
sections: list[ScoredSection] = []
for path in sorted(procedures_dir.glob("*.md")):
raw = path.read_text(encoding="utf-8")
meta, body = _parse_frontmatter(raw)
title = meta.get("title", path.stem)
doc = Document(
document_id=meta.get("document_id", path.stem),
title=title,
version=meta.get("version", "1.0"),
title_tokens=_tokenize(title),
)
for heading, text in _split_sections(body):
sections.append(
ScoredSection(
document=doc,
heading=heading,
text=text,
heading_tokens=_tokenize(heading),
body_tokens=_tokenize(text),
)
)
return sections
class DemoKnowledgeProvider:
"""Deterministic extractive retrieval over the local procedure Markdown files.
Not a generative model: it scores sections with TF-IDF-weighted keyword overlap
(downweighting terms common across the whole corpus, like "vehicle", in favor of
distinctive ones, like "damage") and returns real excerpts, never invented text.
"""
name = "demo"
def __init__(self) -> None:
settings = get_settings()
self._settings = settings
self._procedures_dir = Path(settings.knowledge_dir)
self._sections = _load_sections(self._procedures_dir)
self._document_count = len({s.document.document_id for s in self._sections})
self._idf = self._build_idf(self._sections)
@staticmethod
def _build_idf(sections: list[ScoredSection]) -> dict[str, float]:
n = len(sections) or 1
doc_freq: dict[str, int] = {}
for section in sections:
doc = section.document
all_tokens = doc.title_tokens | section.heading_tokens | section.body_tokens
for token in all_tokens:
doc_freq[token] = doc_freq.get(token, 0) + 1
return {token: math.log((n + 1) / (df + 1)) + 1 for token, df in doc_freq.items()}
def health(self) -> KnowledgeHealth:
return KnowledgeHealth(
provider=self.name,
available=True,
detail="Deterministic keyword-matching demo provider; no external service.",
tenant=self._settings.ragcore_tenant,
workspace=self._settings.ragcore_workspace,
collection=self._settings.ragcore_collection,
document_count=self._document_count,
)
def _score(self, query_tokens: set[str], section: ScoredSection) -> float:
score = 0.0
for token in query_tokens:
idf = self._idf.get(token, 0.0)
if idf == 0.0:
continue
if token in section.heading_tokens:
score += 3 * idf
elif token in section.document.title_tokens:
score += 2 * idf
elif token in section.body_tokens:
score += idf
return score
def ask(self, question: str, correlation_id: str) -> GroundedAnswer:
query_tokens = _tokenize(question)
scored = [
(self._score(query_tokens, section), section)
for section in self._sections
]
scored = [(score, section) for score, section in scored if score > 0]
scored.sort(key=lambda item: item[0], reverse=True)
top = scored[:3]
if not top:
return GroundedAnswer(
answer="No matching procedure was found for this question.",
evidence_state="insufficient",
sources=[],
provider=self.name,
correlation_id=correlation_id,
)
sources = [
SourceCard(
document_id=section.document.document_id,
title=section.document.title,
version=section.document.version,
section=section.heading,
excerpt=(section.text[:400] + "…") if len(section.text) > 400 else section.text,
)
for _, section in top
]
if top[0][0] < 3:
return GroundedAnswer(
answer=(
"The available procedures do not clearly answer this question. "
"The closest matches are included below for review."
),
evidence_state="insufficient",
sources=sources,
provider=self.name,
correlation_id=correlation_id,
)
lead_section = top[0][1]
answer = (
f'Per "{lead_section.document.title}" (v{lead_section.document.version}), '
f'section "{lead_section.heading}": {lead_section.text.splitlines()[0][:300]}'
)
return GroundedAnswer(
answer=answer,
evidence_state="grounded",
sources=sources,
provider=self.name,
correlation_id=correlation_id,
)