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FabledScribe/src/fabledassistant/services/article_context.py
T
bvandeusen 7bd1548f71 fix(discuss): hard-fail empty articles and skip RAG on seed turn
Discuss flow was hallucinating unrelated content when article
extraction returned empty or RAG pulled in orphan notes that looked
more relevant than the generic seed prompt.

- seed_article_discussion raises EmptyArticleError on empty body;
  briefing and /news routes return 422 instead of staging an empty
  synthetic tool result.
- build_context skips RAG auto-injection when user_message matches
  ARTICLE_DISCUSS_SEED so the article IS the context on turn one;
  follow-up turns keep RAG on.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-14 18:13:17 -04:00

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"""Prepare article bodies as conversation-ready context.
Used by the briefing ``discuss-article`` flow and the ``/news`` discuss button.
A raw trafilatura extraction is often too large to drop whole into a chat
history without eating the context window, so this module runs a map-reduce
step over oversized articles and returns a compact, structured context that
still preserves the article's meaning across sections.
Small articles pass through unchanged — map-reduce only fires when the raw
body exceeds CHAR_BUDGET. The output is cached on ``rss_items.context_prepared``
by the caller, so repeat discuss-clicks on the same article skip this work
entirely.
The module also owns ``seed_article_discussion``, the shared routine that
stages a synthetic ``read_article`` tool exchange plus a conversational seed
prompt into a conversation. Both the briefing and ``/news`` entry points call
it so the two flows stay byte-identical — the only thing that differs between
them is whether the conversation already existed or was freshly created.
"""
from __future__ import annotations
import asyncio
import logging
import re
from fabledassistant.models import async_session
from fabledassistant.models.rss_feed import RssItem
from fabledassistant.services.chat import add_message
from fabledassistant.services.llm import generate_completion
logger = logging.getLogger(__name__)
# ~12k tokens at 4 chars/token. Comfortably under OLLAMA_NUM_CTX=16384
# with room left for system prompt, chat history, and the assistant reply.
CHAR_BUDGET = 48_000
# Chunk size for the map step on oversized articles. Overlap preserves
# context across paragraph boundaries that happen to land mid-sentence.
CHUNK_CHARS = 8_000
CHUNK_OVERLAP = 400
_PARA_SPLIT = re.compile(r"\n\s*\n")
def _chunk_by_paragraph(body: str) -> list[str]:
"""Split ``body`` into chunks of up to CHUNK_CHARS, respecting paragraphs.
Paragraphs longer than CHUNK_CHARS are split mid-paragraph as a last
resort. Adjacent chunks share CHUNK_OVERLAP chars of trailing text so
a sentence straddling the boundary stays readable on both sides.
"""
paragraphs = [p.strip() for p in _PARA_SPLIT.split(body) if p.strip()]
chunks: list[str] = []
current: list[str] = []
current_len = 0
for para in paragraphs:
para_len = len(para)
if para_len > CHUNK_CHARS:
if current:
chunks.append("\n\n".join(current))
current, current_len = [], 0
for i in range(0, para_len, CHUNK_CHARS - CHUNK_OVERLAP):
chunks.append(para[i : i + CHUNK_CHARS])
continue
if current_len + para_len + 2 > CHUNK_CHARS and current:
chunks.append("\n\n".join(current))
tail = current[-1][-CHUNK_OVERLAP:] if current else ""
current = [tail, para] if tail else [para]
current_len = len(tail) + para_len + (2 if tail else 0)
else:
current.append(para)
current_len += para_len + 2
if current:
chunks.append("\n\n".join(current))
return chunks
async def _summarize_chunk(title: str, chunk: str, index: int, total: int, model: str) -> str:
"""Map-step summary of one article chunk.
Aims for ~300 words of dense, factual prose — not bullet points — so the
downstream chat model can quote from it naturally.
"""
messages = [
{
"role": "system",
"content": (
"You are summarizing one section of a larger article so a downstream "
"conversation model can discuss the full article without having to read "
"every word.\n\n"
"Requirements:\n"
"- 250350 words of dense factual prose\n"
"- Preserve specific claims, numbers, names, and quotes\n"
"- Do NOT editorialize or add analysis\n"
"- Do NOT use bullet points or headings\n"
"- Do NOT say 'this section' or 'this article' — write content, not meta"
),
},
{
"role": "user",
"content": (
f"Article: {title}\n"
f"Section {index + 1} of {total}:\n\n{chunk}"
),
},
]
try:
# Pin num_ctx — same rationale as services/research.py:66. A large
# chunk plus system prompt can push well past the default window;
# silent truncation here would drop the tail of the chunk without
# any error, producing a misleading summary.
raw = await generate_completion(
messages, model, max_tokens=600, num_ctx=16384
)
return raw.strip()
except Exception:
logger.warning(
"Article chunk summary failed for section %d/%d of '%s'",
index + 1, total, title, exc_info=True,
)
# Fall back to the raw chunk truncated to ~1500 chars so the overall
# pipeline still delivers something rather than dropping the section.
return chunk[:1500]
async def prepare_article_context(
title: str,
url: str,
body: str,
model: str,
) -> str:
"""Return a conversation-ready context block for ``body``.
- Small article (≤ CHAR_BUDGET): returns ``body`` unchanged.
- Oversized article: runs a parallel map step over paragraph-aware
chunks and concatenates the summaries under section headers.
The returned string is what should go into the ``read_article`` synthetic
tool-result in chat history. Callers are responsible for caching it to
``rss_items.context_prepared``.
"""
body = body or ""
if len(body) <= CHAR_BUDGET:
return body
chunks = _chunk_by_paragraph(body)
logger.info(
"Article '%s' is %d chars, map-reducing into %d chunks",
title, len(body), len(chunks),
)
summaries = await asyncio.gather(
*[
_summarize_chunk(title, chunk, i, len(chunks), model)
for i, chunk in enumerate(chunks)
]
)
header = (
f"(This article was longer than the chat window could hold verbatim, "
f"so the full text was split into {len(chunks)} sections and each was "
"summarized below. Each section preserves specific claims, numbers, "
"and quotes from the original.)\n\n"
)
parts = [
f"## Section {i + 1}\n\n{summary}"
for i, summary in enumerate(summaries)
]
return header + "\n\n".join(parts)
# Conversational seed prompt for article discussions. Kept here so both the
# briefing and /news entry points use the exact same wording. See
# feedback_discuss_prompt_style memory: numbered checklists produce
# assignment-completion responses; this conversational seed opens a dialogue.
ARTICLE_DISCUSS_SEED = (
"I want to talk about this article. Start with a substantive summary "
"of what it's arguing and the key evidence it uses, then tell me what "
"stood out to you or seems worth pushing back on. I'll ask follow-ups "
"from there."
)
class EmptyArticleError(Exception):
"""Raised when an article has no extractable body text.
Callers (the briefing and /news discuss routes) map this to a 422 so the
user sees a clear error instead of a hallucinated summary built from an
empty synthetic tool result.
"""
async def seed_article_discussion(
conv_id: int,
item: RssItem,
model: str,
) -> str:
"""Stage the synthetic read_article tool exchange + conversational seed.
Used by both the briefing ``discuss_article`` route and the ``/news``
``from-article`` conversation creator. Handles the three-layer cache
(``context_prepared`` → ``content_full`` → fresh fetch) and inserts two
messages into ``conv_id``:
1. An assistant message with a synthetic ``read_article`` tool_call whose
``result.content`` carries the prepared article context. The message
also carries ``msg_metadata={"rss_item_id": ...}`` so the post-generation
hook in ``generation_task.py`` can locate it and persist the first
reply as a discussion-summary Note.
2. A user message with the shared conversational seed prompt.
Returns the seed prompt string so callers can pass it to ``run_generation``
as ``user_content``.
"""
# Avoid circulars: rss helper imports article_context indirectly nowhere,
# but keep this local for symmetry with the route-level imports it
# replaces.
from fabledassistant.services.rss import get_or_fetch_full_article
if item.context_prepared:
article_content = item.context_prepared
else:
raw_body = await get_or_fetch_full_article(item) or item.content or ""
if not raw_body.strip():
# Hard-fail rather than stage an empty synthetic tool result.
# An empty `content` field silently tells the model "the article
# has nothing in it" and it confabulates from RAG/history. Better
# to surface a clean error to the user.
logger.warning(
"Article discussion aborted: empty body for rss_item %s (%s)",
item.id, item.url,
)
raise EmptyArticleError(
"Couldn't extract any readable text from this article."
)
article_content = await prepare_article_context(
item.title or "", item.url, raw_body, model,
)
if not article_content.strip():
raise EmptyArticleError(
"Couldn't extract any readable text from this article."
)
async with async_session() as session:
fresh = await session.get(RssItem, item.id)
if fresh is not None:
fresh.context_prepared = article_content
await session.commit()
synthetic_tool_calls = [{
"function": "read_article",
"arguments": {"url": item.url},
"result": {
"success": True,
"type": "article_content",
"url": item.url,
"content": article_content,
"truncated": False,
},
}]
await add_message(
conv_id,
"assistant",
"",
status="complete",
tool_calls=synthetic_tool_calls,
msg_metadata={"rss_item_id": item.id, "article_seed": True},
)
await add_message(conv_id, "user", ARTICLE_DISCUSS_SEED)
return ARTICLE_DISCUSS_SEED