forked from Zakaria/hermes-agent
Zakaria
80 lines
2.4 KiB
Python
80 lines
2.4 KiB
Python
"""Anthropic prompt caching strategy.
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Single layout: ``system_and_3``. 4 cache_control breakpoints — system
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prompt + last 3 non-system messages, all at the same TTL (5m or 1h).
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Reduces input token costs by ~75% on multi-turn conversations within a
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single session.
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Pure functions -- no class state, no AIAgent dependency.
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"""
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import copy
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from typing import Any, Dict, List
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def _apply_cache_marker(msg: dict, cache_marker: dict, native_anthropic: bool = False) -> None:
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"""Add cache_control to a single message, handling all format variations."""
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role = msg.get("role", "")
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content = msg.get("content")
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if role == "tool":
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if native_anthropic:
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msg["cache_control"] = cache_marker
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return
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if content is None or content == "":
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msg["cache_control"] = cache_marker
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return
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if isinstance(content, str):
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msg["content"] = [
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{"type": "text", "text": content, "cache_control": cache_marker}
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]
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return
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if isinstance(content, list) and content:
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last = content[-1]
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if isinstance(last, dict):
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last["cache_control"] = cache_marker
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def _build_marker(ttl: str) -> Dict[str, str]:
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"""Build a cache_control marker dict for the given TTL ('5m' or '1h')."""
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marker: Dict[str, str] = {"type": "ephemeral"}
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if ttl == "1h":
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marker["ttl"] = "1h"
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return marker
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def apply_anthropic_cache_control(
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api_messages: List[Dict[str, Any]],
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cache_ttl: str = "5m",
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native_anthropic: bool = False,
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) -> List[Dict[str, Any]]:
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"""Apply system_and_3 caching strategy to messages for Anthropic models.
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Places up to 4 cache_control breakpoints: system prompt + last 3 non-system
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messages, all at the same TTL.
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Returns:
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Deep copy of messages with cache_control breakpoints injected.
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"""
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messages = copy.deepcopy(api_messages)
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if not messages:
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return messages
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marker = _build_marker(cache_ttl)
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breakpoints_used = 0
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if messages[0].get("role") == "system":
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_apply_cache_marker(messages[0], marker, native_anthropic=native_anthropic)
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breakpoints_used += 1
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remaining = 4 - breakpoints_used
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non_sys = [i for i in range(len(messages)) if messages[i].get("role") != "system"]
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for idx in non_sys[-remaining:]:
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_apply_cache_marker(messages[idx], marker, native_anthropic=native_anthropic)
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return messages
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