Files
chat/chat/services/thread_detection.py
T
2026-04-26 20:10:36 -04:00

90 lines
2.9 KiB
Python

"""Thread-detection service (T55).
On scene close, classify the transcript into thread open/update/close
candidates. Returns ThreadCandidate list; caller (T58 scene compression)
emits one thread_opened/thread_updated/thread_closed event per candidate.
"""
from __future__ import annotations
from pydantic import BaseModel, Field
from chat.llm.classify import classify
from chat.llm.client import LLMClient
class ThreadCandidate(BaseModel):
action: str # "open" | "update" | "close"
title: str = "" # required for "open"; ignored otherwise
summary: str = ""
existing_thread_id: str | None = None # required for "update" / "close"
class ThreadDetectionResult(BaseModel):
candidates: list[ThreadCandidate] = Field(default_factory=list)
_SYSTEM = (
"You analyze a closed scene's transcript to identify narrative "
"threads (unresolved arcs, dangling questions, promises made, "
"open obligations). Choose actions:\n"
"- 'open': a NEW thread the scene introduced. Provide title (short "
"noun phrase) + summary (one sentence).\n"
"- 'update': an EXISTING open thread that the scene developed. "
"Provide existing_thread_id + new summary.\n"
"- 'close': an EXISTING open thread that the scene resolved. "
"Provide existing_thread_id; summary may capture the resolution.\n"
"Conservative bias: most scenes do NOT open new threads. Only "
"produce candidates when the transcript clearly justifies them. "
"Output strict JSON matching the schema."
)
async def detect_threads(
client: LLMClient,
*,
classifier_model: str,
scene_transcript: list[dict], # [{speaker, text}, ...]
open_threads: list[dict], # [{thread_id, title, summary}, ...]
timeout_s: float = 30.0,
) -> ThreadDetectionResult:
"""Classify scene close into thread open/update/close candidates."""
if not scene_transcript:
return ThreadDetectionResult()
transcript_lines = [
f"{turn.get('speaker', 'unknown')}: {turn.get('text', '')}"
for turn in scene_transcript
]
threads_lines = []
if open_threads:
threads_lines.append("Currently open threads:")
for t in open_threads:
threads_lines.append(
f"- thread_id={t['thread_id']} "
f"title={t.get('title', '')} "
f"summary={t.get('summary', '')}"
)
else:
threads_lines.append("No currently open threads.")
user = (
"Scene transcript:\n"
+ "\n".join(transcript_lines)
+ "\n\n"
+ "\n".join(threads_lines)
)
return await classify(
client,
model=classifier_model,
system=_SYSTEM,
user=user,
schema=ThreadDetectionResult,
default=ThreadDetectionResult(),
timeout_s=timeout_s,
)
__all__ = ["ThreadCandidate", "ThreadDetectionResult", "detect_threads"]