From 691de01b79837c92aafe3a142a1ded75dcb6bc18 Mon Sep 17 00:00:00 2001
From: Soulter <905617992@qq.com>
Date: Wed, 26 Mar 2025 00:46:15 +0800
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20feat:=20=E6=94=AF=E6=8C=81=E8=AE=BE?=
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---
 astrbot/core/config/default.py                        |  6 ++++++
 .../core/pipeline/process_stage/method/llm_request.py | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/astrbot/core/config/default.py b/astrbot/core/config/default.py
index 9bcacce9c..793227f3f 100644
--- a/astrbot/core/config/default.py
+++ b/astrbot/core/config/default.py
@@ -49,6 +49,7 @@ DEFAULT_CONFIG = {
         "datetime_system_prompt": True,
         "default_personality": "default",
         "prompt_prefix": "",
+        "max_context_length": -1,
     },
     "provider_stt_settings": {
         "enable": False,
@@ -909,6 +910,11 @@ CONFIG_METADATA_2 = {
                         "type": "string",
                         "hint": "添加之后，会在每次对话的 Prompt 前加上此文本。",
                     },
+                    "max_context_length": {
+                        "description": "最多携带对话数量(条)",
+                        "type": "int",
+                        "hint": "超出这个数量时将丢弃最旧的部分，用户和AI的一轮聊天记为 1 条。-1 表示不限制，默认为不限制。",
+                    },
                 },
             },
             "persona": {
diff --git a/astrbot/core/pipeline/process_stage/method/llm_request.py b/astrbot/core/pipeline/process_stage/method/llm_request.py
index b49cd6581..872875e8f 100644
--- a/astrbot/core/pipeline/process_stage/method/llm_request.py
+++ b/astrbot/core/pipeline/process_stage/method/llm_request.py
@@ -34,6 +34,9 @@ class LLMRequestSubStage(Stage):
         self.provider_wake_prefix = ctx.astrbot_config["provider_settings"][
             "wake_prefix"
         ]  # str
+        self.max_context_length = ctx.astrbot_config["provider_settings"][
+            "max_context_length"
+        ]  # int
 
         for bwp in self.bot_wake_prefixs:
             if self.provider_wake_prefix.startswith(bwp):
@@ -123,6 +126,14 @@ class LLMRequestSubStage(Stage):
         if isinstance(req.contexts, str):
             req.contexts = json.loads(req.contexts)
 
+        # max context length
+        if (
+            self.max_context_length != -1 # -1 为不限制
+            and len(req.contexts) // 2 > self.max_context_length
+        ):
+            logger.debug("上下文长度超过限制，将截断。")
+            req.contexts = req.contexts[-self.max_context_length * 2 :]
+
         try:
             need_loop = True
             while need_loop: