Files
simbarag/blueprints/conversation/memory.py
T
ryan 891f44c1a9 Keep the chat prompt prefix stable for llama-server prompt caching
llama-server only reuses a byte-identical prompt prefix. Several things
changed the prefix every turn, forcing most of the prompt to be re-prefilled:

- Memories: rank still chooses which memories fit the budget, but the chosen
  ones are emitted in stored order, so the block is identical across queries.
- History trimming: the conversation-evidence summary is only included when
  turns were actually dropped (it duplicated retained turns otherwise). On
  overflow, old turns are dropped at stable cut points down to ~65% of the
  budget, so the retained prefix holds for several turns instead of shifting
  by one turn every request.
- Tools: TOOL_ROUTING_MODE=static (default) binds the full role-appropriate
  tool set in registration order with no discovery tool; admin gating is
  unchanged. TOOL_ROUTING_MODE=dynamic keeps the keyword router.
- Observability: per-call model_calls in the stream_request log now include
  cached_prompt_tokens when the provider reports cache reads.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-12 23:01:46 -04:00

81 lines
3.2 KiB
Python

from collections import Counter
from .models import UserMemory
from .prompts import SIMBA_SYSTEM_PROMPT
from .context import estimate_tokens
from .tool_routing import words
MEMORY_BUDGET_TOKENS = 1000
async def get_memories_for_user(user_id: str) -> list[str]:
"""Return all memory content strings for a user, ordered by most recently updated."""
memories = await UserMemory.filter(user_id=user_id).order_by("-updated_at")
return [m.content for m in memories]
def rank_memories(memories: list[str], query: str = "") -> list[str]:
"""Rank lexical relevance first, with a bounded recency bonus.
Input order is newest first. No database fields or stored memories change.
"""
stop_words = words(
"a an the and or of for to in on is are was were i me my you your what how do does can please about remember"
)
terms = words(query) - stop_words
if not terms:
return list(memories)
# Normalize simple plurals to match e.g. recipes/recipe without dependencies.
def normalize(tokens):
return {t[:-1] if len(t) > 3 and t.endswith("s") else t for t in tokens}
terms = normalize(terms)
scored = []
for index, memory in enumerate(memories):
overlap = len(terms & normalize(words(memory))) / len(terms)
score = (1 + overlap if overlap else 0) + 0.1 / (index + 1)
scored.append((score, index, memory))
return [m for _, _, m in sorted(scored, key=lambda row: (-row[0], row[1]))]
async def build_system_prompt_with_memories(user_id: str, query: str = "") -> str:
memories = await get_memories_for_user(user_id)
if not memories:
return SIMBA_SYSTEM_PROMPT
header = "\n\nUSER MEMORIES (facts the user has asked you to remember):\n"
omission = "\n[Additional saved memories omitted from this prompt.]"
# Reserve wrapper and omission costs so the entire injected memory block fits.
used = estimate_tokens(header) + estimate_tokens(omission)
chosen = Counter()
for memory in rank_memories(memories, query):
cost = estimate_tokens(f"- {memory}\n")
if used + cost <= MEMORY_BUDGET_TOKENS:
chosen[memory] += 1
used += cost
# Rank only chooses what fits; emit in stored order so the system prompt is
# byte-identical across queries and llama-server can reuse its KV cache.
selected = []
for memory in memories:
if chosen[memory]:
chosen[memory] -= 1
selected.append(memory)
block = "\n".join(f"- {m}" for m in selected)
if len(selected) < len(memories):
block += omission
if not selected:
return SIMBA_SYSTEM_PROMPT
return f"{SIMBA_SYSTEM_PROMPT}{header}{block}"
async def save_memory(user_id: str, content: str) -> str:
"""Save a new memory or touch an existing one (exact-match dedup)."""
existing = await UserMemory.filter(user_id=user_id, content=content).first()
if existing:
existing.updated_at = None # auto_now=True will refresh it on save
await existing.save(update_fields=["updated_at"])
return "Memory already exists (refreshed)."
await UserMemory.create(user_id=user_id, content=content)
return "Memory saved."