refactor(agent-runner): remove host context windowing

docs/agent-runner-pluginization/AGENT_CONTEXT_PROTOCOL.md

@@ -14,7 +14,7 @@
 - ✅ `AgentRunAPIProxy.state` — get/set/delete API
 - ✅ EventLog / Transcript / ArtifactStore — host 事实源
 - ✅ PersistentStateStore — 持久化状态存储
-- ✅ `max-round` 已从协议实体中移除；如某 runner 仍需要类似历史窗口参数，应作为 runner binding config 由插件 manifest 暴露，而不是 Host / Pipeline 协议字段
+- ✅ `max-round` / host-side history window 已从 LangBot Host/Pipeline 语义中移除；如某 runner 仍需要类似参数，应由该 runner 自己解释配置
 - ✅ 外部 harness context projection 已用 Claude Code runner 做 MVP 验证：context 文件、skill 投影、MCP 配置和 host-owned resume state
 
 ## 1. 设计原则
@@ -41,7 +41,7 @@
 
 如果某个 runner 仍需要“最多读取多少轮历史”这样的策略参数，应由该 runner 在自己的 manifest/config schema 中声明，并作为 binding config 存到 `ctx.config` / `runner_config`。Host 只提供 history pull API、cursor、hard cap 和权限边界；runner 自己决定是否读取、读取多少、如何截断和压缩。
 
-当前 official local-agent 方向是通过 Host history API 拉取 transcript，并由 runner 自己管理模型上下文。它不依赖 Pipeline adapter 下发的 `max-round` / bootstrap 窗口。
+当前 official local-agent 方向是通过 Host history API 拉取 transcript，并由 runner 自己管理模型上下文。它不依赖 Pipeline adapter 下发历史窗口。
 
 新协议不应该问“LangBot 每轮裁几轮历史给 agent”，而应该问：
 
@@ -58,7 +58,7 @@
 - `Transcript`: Host 从 EventLog 投影出的对话视图，用于 UI、审计和按需历史读取。
 - `Working context`: Agent 本轮实际送进模型或 runtime 的上下文，由 AgentRunner 决定。
 
-LangBot 可以为简单 runner 提供 bootstrap window，但这只是 convenience，不是主架构。
+LangBot 不再提供 host-side bootstrap window。简单 runner 如果需要历史窗口，应在 runner 内部通过 Host history API 拉取并裁剪。
 
 ## 2. Event 到来时传什么
 
@@ -117,22 +117,11 @@ class AgentRunContext(BaseModel):
 
 这些会破坏跨进程序列化成本、泄露范围、KV cache 稳定性，也会迫使 host 替 agent 做 context 策略。
 
-### 2.3 可选 bootstrap
+### 2.3 不提供 Host Bootstrap Window
 
-根据 runner manifest 可以提供可选 bootstrap：
+`AgentRunContext.bootstrap` 可以作为协议里的可选扩展字段保留，但 LangBot Host 默认不填历史窗口，也不通过 Pipeline 配置决定窗口大小。
 
-```yaml
+如果 runner 需要类似 `recent_tail` 的策略，它应在自己的 manifest/config schema 中声明参数，并在 runner 内部通过 `history_page` / `history_search` 读取、裁剪和压缩历史。Host 只负责权限、分页、hard cap 和事实源。
-context:
-  bootstrap: none | current_event | recent_tail | summary_tail
-  max_inline_events: 0
-  max_inline_bytes: 0
-```
-
-建议默认：
-
-- 自管 runtime：`bootstrap: current_event`
-- 简单 HTTP runner：`bootstrap: recent_tail`
-- runner 如果需要 `recent_tail` 策略，应通过自己的 binding config 声明窗口大小；Host 不把 `max-round` 作为通用协议字段扩展。
 
 ## 3. ContextAccess
 
@@ -335,7 +324,7 @@ LangBot core 不应内置官方 agent 的业务流程：
 
 **已完成（当前分支）**：
 
-- ✅ `max-round` 不再是协议字段；类似历史窗口策略属于 runner binding config，而不是 Host / Pipeline 通用语义
+- ✅ `max-round` 不再是协议字段，也不再是 Host / Pipeline 通用语义
 - ✅ 新 runner 默认不收到历史窗口
 - ✅ `AgentRunContext` 增加 `context` / cursor / access capabilities
 - ✅ `AgentRunAPIProxy` 增加 history / events / artifacts / state API

docs/agent-runner-pluginization/IMPLEMENTATION_PLAN.md

@@ -156,7 +156,7 @@ class AgentRunnerDescriptor(BaseModel):
 
 ### 3.4 context_builder.py / pipeline_adapter.py
 
-`context_builder.py` 只负责从 `AgentEventEnvelope + AgentBinding` 构造 SDK v1 `AgentRunContext`。Pipeline Query 的读取、参数过滤、prompt 提取和 `max-round` bootstrap 映射都属于 `PipelineAdapter`，不再放进 context builder。
+`context_builder.py` 只负责从 `AgentEventEnvelope + AgentBinding` 构造 SDK v1 `AgentRunContext`。Pipeline Query 的读取、参数过滤和 prompt 提取属于 `PipelineAdapter`，但 PipelineAdapter 不再做历史窗口裁剪或 bootstrap 打包。
 
 当前消息 Pipeline 进入 agent runner 的路径：
 
@@ -183,7 +183,7 @@ Protocol v1 context 的稳定字段：
 - `state`: `PersistentStateStore` 读取的 host-managed scoped state snapshot
 - `runtime`: host/version/workspace/bot/query/trace/deadline
 - `config`: 当前 binding 对该 runner id 的配置，即 `runner_config`
-- `bootstrap`: 可选小窗口，不是完整历史
+- `bootstrap`: 可选扩展字段；LangBot Host 默认不填历史窗口
 - `adapter`: Pipeline 或其它入口 adapter 的元数据
 
 Pipeline adapter 的 `prompt` 和公开业务变量不进入顶层协议字段：
@@ -191,58 +191,36 @@ Pipeline adapter 的 `prompt` 和公开业务变量不进入顶层协议字段
 - filtered params -> `ctx.adapter.extra["params"]`
 - legacy/effective prompt 可以暂存到 `ctx.adapter.extra["prompt"]`，但 official
   runner 不应把它当作行为契约
-- `max-round` working window 可以保留在 Pipeline adapter 兼容层，但 official
+- LangBot Host 不生成 `bootstrap.messages`、`adapter_messages` 或 context packaging 元数据
-  `local-agent` 不消费该 bootstrap/window
-- packaging 元数据 -> `ctx.runtime.metadata.context_packaging`
 
 现阶段不要把新的压缩或 token-budget 裁剪塞回 Pipeline stage。Pipeline 只负责入口适配；完整历史和长期上下文由 EventLog / Transcript / pull APIs / future ContextCompressor 支撑。
 
 ### 3.4.1 Agentic context plan
 
-本轮只在 `PipelineAdapter` 中保留 `max-round` working window，不改变 user-round 选择规则。
 EventLog / Transcript / Host pull APIs 已落地，`ContextCompressor` 仍是设计预留。
 目标是让 Pipeline 逐步退化为入口 adapter，让 AgentRunner 层拥有上下文打包职责。
 
-建议最终拆成四个 host-side 服务：
+建议 Host 保持三类事实源和受限 API：
 
 ```text
 ConversationStore / EventLog
   -> durable append-only raw messages, events, tool results, artifact refs
 ConversationProjection
   -> converts events into agent-readable conversation history
-PipelineAdapter bootstrap policy
-  -> builds the bounded working context for one run
 ContextCompressor
-  -> creates and updates summaries/checkpoints when thresholds are exceeded
+  -> future optional service for summaries/checkpoints, requested and consumed by runners
 ```
 
 关键原则：
 
 - 完整历史属于 LangBot host，不属于插件实例。插件仍是 singleton/stateless。
-- `ctx.bootstrap.messages` 是 optional working context window，不是完整 conversation dump。
+- `ctx.bootstrap.messages` 不是 Host 默认下发的 working context。
 - 每轮不能全量复制/序列化完整历史给插件 runtime；否则长会话会产生 O(n) 成本和跨进程 payload 膨胀。
-- `max-round` 的 user-round 规则只属于 Pipeline adapter 的 bootstrap 策略。
+- `max-round` 或类似窗口规则不属于 LangBot Host / Pipeline 语义。
-- LiteLLM 接入后，context packaging 应升级为 token budget / summary / pull API 协作策略。
+- LiteLLM 接入后，模型窗口元信息应作为 resource/runtime metadata 暴露给 runner，由 runner 决定预算和压缩策略。
 - `ContextCompressor` 生成的是派生 summary/checkpoint，不能覆盖或删除 raw history。
 - 重启恢复依赖持久化 store 和 summary checkpoint，不依赖 `SessionManager` 里的进程内 conversation list。
 
-后续 `AgentRunContext` 可增加：
-
-```python
-context_request: AgentContextRequest | None
-context_packaging: ContextPackagingMetadata
-```
-
-建议语义：
-
-- `context_request.mode`: AgentRunner manifest / binding config 请求的 `max_round`、`token_budget`、`summary_hybrid`、`external_session`
-- `context_request.budget`: 模型窗口、预留输出 token、工具/RAG 预算等偏好
-- `context_packaging.policy`: Host 本次实际采用的打包策略
-- `context_packaging.delivered_count`: 本次下发的历史消息数
-- `context_packaging.source_total_count`: packager 可见的原始历史消息数
-- `context_packaging.messages_complete`: 本窗口是否已经包含完整历史
-- `context_packaging.cursor_before`: 未来通过 host API 读取更早历史的 cursor
-
 未来需要的受限 API：
 
 ```python
@@ -256,7 +234,7 @@ page size、总字节数、deadline 和可访问 conversation。
 
 ### 3.4.2 Large artifacts and tool collaboration
 
-大文件、多模态输入和工具产物不要内联进 bootstrap messages 或 tool result。后续统一用
+大文件、多模态输入和工具产物不要内联进 prompt、bootstrap 或 tool result。后续统一用
 artifact/resource ref 协作：
 
 - message/content 里只放小文本和必要摘要。
@@ -512,7 +490,7 @@ async def run_from_query(query: pipeline_query.Query) -> AsyncGenerator[Message
 ### Step 4：local-agent parity
 
 - 使用静态绑定配置 `ctx.config["prompt"]`，不读取 `ctx.adapter.extra["prompt"]`。
-- 通过 Host history API 拉取 transcript，不读取 `ctx.bootstrap.messages` 或 `ctx.adapter.adapter_messages`。
+- 通过 Host history API 拉取 transcript，不读取 `ctx.bootstrap.messages` 或 adapter window 字段。
 - 当前 user message 从 `ctx.input.contents` 构造，保留多模态内容。
 - RAG 只替换/插入文本部分，不丢图片/文件。
 - streaming/non-streaming 默认跟随 `runtime.metadata.streaming_supported`。

docs/agent-runner-pluginization/OFFICIAL_RUNNER_PLUGINS.md

@@ -183,10 +183,9 @@ LangBot core 不应为了 local-agent 保留业务编排逻辑。local-agent 的
 - `ctx.runtime.metadata.streaming_supported`：当前 adapter 是否能消费流式输出。
 - 宿主代理 action：模型、工具、知识库、rerank 调用必须通过 `run_id` 校验资源权限。
 
-`local-agent` 不应消费 Pipeline adapter 生成的 `max-round` / `bootstrap`
+`local-agent` 不应消费 Pipeline adapter 生成的历史窗口，也不应读取
-窗口，也不应读取 `ctx.adapter.extra.prompt`。它应从绑定配置读取静态
+`ctx.adapter.extra.prompt`。它应从绑定配置读取静态 `prompt`，并通过 Host
-`prompt`，并通过 Host history API 拉取 transcript。Pipeline adapter 可以继续为旧入口
+history API 拉取 transcript。Pipeline adapter 不保留 Host-side window 兼容逻辑。
-保留 `max-round` 兼容逻辑，但这不是 official local-agent 的行为契约。
 
 建议 local-agent manifest 使用 hybrid 或 self-managed context：
 

docs/agent-runner-pluginization/PROTOCOL_V1.md

@@ -11,7 +11,7 @@
 - ✅ Host 支持 `run_id` session authorization
 - ✅ Host 能从当前 Pipeline 入口生成 event-first context
 - ✅ `messages` 降级为 optional bootstrap
-- ✅ `max-round` 不出现在协议实体中；类似历史窗口参数若存在，应来自 runner manifest/config schema，并作为 binding config 进入 `ctx.config`
+- ✅ `max-round` 不出现在协议实体中，也不属于 Host / Pipeline 语义；类似参数若存在，由 runner 自己解释 `ctx.config`
 - ✅ Proxy 覆盖 model、tool、knowledge、state/storage
 - ✅ History / Event / Artifact / State API 已落地
 - ✅ EventLog / Transcript / ArtifactStore / PersistentStateStore 已落地
@@ -142,13 +142,13 @@ class AgentRunnerContextPolicy(BaseModel):
     wants_static_context_refs: bool = True
 ```
 
-Host 使用该声明决定是否给 runner inline bootstrap history。默认原则：
+Host 不使用该声明给 runner inline 历史窗口。默认原则：
 
 - Host 不得默认 inline 全量历史。
-- Host 默认只 inline 当前 event / input 和 context handles。
+- Host 只 inline 当前 event / input 和 context handles。
 - Runner 拥有 working context assembly。
 - Runner 可在授权后通过 Host history / event / artifact / state APIs 拉取更多上下文。
-- `max-round` 不属于 Protocol v1 字段，也不属于 Pipeline / Host 通用语义。
+- `max-round` 或类似窗口参数不属于 Protocol v1 字段，也不属于 Pipeline / Host 通用语义；如果某个 runner 需要，应由 runner 自己解释 `ctx.config`。
 
 ## 4. Run 协议
 
@@ -193,7 +193,7 @@ class AgentRunContext(BaseModel):
 
 - `event` 是必选字段，Protocol v1 是 event-first。
 - `input` 表示当前事件的主输入，不等于历史消息。
-- `bootstrap` 是可选字段，不是完整 history。
+- `bootstrap` 是可选字段；LangBot Host 默认不填历史窗口。
 - `adapter` 只放 Pipeline adapter 字段，runner 不应依赖它做长期能力。
 - `config` 是 Host binding config，不是插件实例状态。
 
@@ -342,10 +342,10 @@ class BootstrapContext(BaseModel):
 
 约束：
 
-- `bootstrap.messages` 是 host convenience，不是协议核心。
+- `bootstrap.messages` 不是 LangBot Host 的默认行为。
-- 自管 context runner 默认应收到空 bootstrap 或只收到当前 event。
+- 自管 context runner 默认应收到空 bootstrap。
 - Host 不应为了”帮 agent 更聪明”而自动拼接完整 transcript。
-- 类似历史窗口策略应由具体 runner 的 binding config 表达；new/official runners 不应依赖 Pipeline adapter 下发的 bootstrap window。
+- 类似历史窗口策略应由具体 runner 自己解释 binding config，并通过 Host history API 拉取历史；new/official runners 不应依赖 Pipeline adapter 下发历史窗口。
 
 ### 4.10 RuntimeContext
 
@@ -685,7 +685,7 @@ Protocol v1 已在当前分支完成：
 - ✅ Host 支持 `run_id` session authorization
 - ✅ Host 能从当前 Pipeline 入口生成 event-first context
 - ✅ `messages` 降级为 optional bootstrap
-- ✅ `max-round` 不出现在协议实体中；类似参数属于具体 runner binding config
+- ✅ `max-round` 不出现在协议实体中，也不属于 Host / Pipeline 语义
 - ✅ Proxy 至少覆盖 model、tool、knowledge、state/storage
 - ✅ History / event / artifact API 已落地
 - ✅ EventLog / Transcript / ArtifactStore / PersistentStateStore 已落地

src/langbot/pkg/agent/runner/config_migration.py

@@ -114,6 +114,9 @@ class ConfigMigration:
         if old_runner_name:
             old_config = ai_config.get(old_runner_name, {})
             if old_config:
+                old_config = dict(old_config)
+                if runner_id == OLD_RUNNER_TO_PLUGIN_RUNNER_ID['local-agent']:
+                    old_config.pop('max-round', None)
                 return ConfigMigration.normalize_runner_config_for_migration(runner_id, old_config)
 
         return {}

src/langbot/pkg/agent/runner/context_builder.py

@@ -296,8 +296,6 @@ class AgentRunContextBuilder:
         adapter_context = {
             'query_id': None,
             'pipeline_uuid': binding.pipeline_uuid,
-            'max_round': binding.max_round,  # For reference only
-            'adapter_messages': [],
             'extra': {},
         }
 
@@ -316,7 +314,7 @@ class AgentRunContextBuilder:
             'state': state,
             'runtime': runtime,
             'config': binding.runner_config,
-            'bootstrap': None,  # Optional - no messages inlined by default
+            'bootstrap': None,
             'adapter': adapter_context,
             'metadata': {},  # Additional metadata
         }

src/langbot/pkg/agent/runner/event_log_store.py

@@ -11,7 +11,6 @@ from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession
 from sqlalchemy.orm import sessionmaker
 
 from ...entity.persistence.event_log import EventLog
-from ...entity.persistence.transcript import Transcript
 
 
 class EventLogStore:

src/langbot/pkg/agent/runner/host_models.py

@@ -8,8 +8,6 @@ import typing
 import pydantic
 
 from langbot_plugin.api.entities.builtin.agent_runner.event import (
-    AgentEventContext,
-    ConversationContext,
     ActorContext,
     SubjectContext,
     RawEventRef,
@@ -172,6 +170,3 @@ class AgentBinding(pydantic.BaseModel):
     # Fields for Pipeline adapter
     pipeline_uuid: str | None = None
     """Pipeline UUID (for Pipeline adapter)."""
-
-    max_round: int | None = None
-    """max-round (for Pipeline adapter bootstrap, not Protocol v1)."""

src/langbot/pkg/agent/runner/orchestrator.py

@@ -133,16 +133,6 @@ class AgentRunOrchestrator:
             # Merge prompt into adapter.extra for Pipeline adapter consumers.
             if 'prompt' in adapter_context:
                 context['adapter']['extra']['prompt'] = adapter_context['prompt']
-            # Merge bootstrap if provided
-            if adapter_context.get('bootstrap'):
-                context['bootstrap'] = adapter_context['bootstrap']
-                # Also expose the bootstrap window through adapter metadata.
-                bootstrap_messages = adapter_context['bootstrap'].get('messages')
-                if bootstrap_messages:
-                    context['adapter']['adapter_messages'] = bootstrap_messages
-            # Merge runtime metadata if provided
-            if adapter_context.get('runtime_metadata'):
-                context['runtime']['metadata'].update(adapter_context['runtime_metadata'])
             # Set query_id if provided
             if adapter_context.get('query_id'):
                 context['runtime']['query_id'] = adapter_context['query_id']

src/langbot/pkg/agent/runner/pipeline_adapter.py

@@ -29,7 +29,6 @@ from .host_models import (
     DeliveryPolicy,
 )
 from . import events as runner_events
-from ...pipeline.msgtrun.round_policy import select_max_round_messages
 
 
 class PipelineAdapter:
@@ -38,7 +37,6 @@ class PipelineAdapter:
     This adapter is responsible for:
     - Converting Query to AgentEventEnvelope
     - Converting Pipeline config to temporary AgentBinding
-    - Handling max-round as bootstrap policy
     - Putting Query-only fields into adapter context
     """
 
@@ -118,10 +116,6 @@ class PipelineAdapter:
         runner_config = ai_config.get('runner_config', {}).get(runner_id, {})
         pipeline_uuid = getattr(query, 'pipeline_uuid', None)
 
-        # Extract max_round for adapter (used in bootstrap, not Protocol v1)
-        # Note: config uses 'max-round' with hyphen, not 'max_round' with underscore
-        max_round = runner_config.get('max-round') or ai_config.get('max-round')
-
         # Build scope
         scope = BindingScope(
             scope_type="pipeline",
@@ -158,45 +152,8 @@ class PipelineAdapter:
             delivery_policy=delivery_policy,
             enabled=True,
             pipeline_uuid=pipeline_uuid,
-            max_round=max_round,
         )
 
-    @classmethod
-    def build_bootstrap_context(
-        cls,
-        query: pipeline_query.Query,
-        binding: AgentBinding,
-    ) -> tuple[dict[str, typing.Any] | None, dict[str, typing.Any]]:
-        """Build bootstrap messages and runtime metadata for Pipeline max-round."""
-        max_round = binding.max_round
-        source_messages = query.messages or []
-        if not max_round or max_round <= 0 or not source_messages:
-            return None, {}
-
-        packaged_messages = select_max_round_messages(source_messages, max_round)
-        bootstrap_messages = [cls._dump_message(msg) for msg in packaged_messages]
-        bootstrap = {
-            "messages": bootstrap_messages,
-            "summary": None,
-            "artifacts": [],
-            "metadata": {},
-        }
-        runtime_metadata = {
-            'context_packaging': {
-                'policy': {
-                    'mode': 'max_round',
-                    'max_round': max_round,
-                },
-                'history': {
-                    'source': 'query.messages',
-                    'source_total_count': len(source_messages),
-                    'delivered_count': len(packaged_messages),
-                    'messages_complete': len(packaged_messages) == len(source_messages),
-                },
-            },
-        }
-        return bootstrap, runtime_metadata
-
     @classmethod
     def build_adapter_context(
         cls,
@@ -204,13 +161,10 @@ class PipelineAdapter:
         binding: AgentBinding,
     ) -> dict[str, typing.Any]:
         """Build Query-derived fields for the Pipeline adapter entry."""
-        bootstrap, runtime_metadata = cls.build_bootstrap_context(query, binding)
         return {
             'params': cls.build_params(query),
             'prompt': cls.build_prompt(query),
-            'bootstrap': bootstrap,
             'query_id': getattr(query, 'query_id', None),
-            'runtime_metadata': runtime_metadata,
         }
 
     @classmethod

src/langbot/pkg/api/http/service/pipeline.py

@@ -19,7 +19,6 @@ default_stage_order = [
     'BanSessionCheckStage',  # 封禁会话检查
     'PreContentFilterStage',  # 内容过滤前置阶段
     'PreProcessor',  # 预处理器
-    'ConversationMessageTruncator',  # 会话消息截断器
     'RequireRateLimitOccupancy',  # 请求速率限制占用
     'MessageProcessor',  # 处理器
     'ReleaseRateLimitOccupancy',  # 释放速率限制占用

src/langbot/pkg/persistence/migrations/dbm001_migrate_v3_config.py

@@ -118,9 +118,6 @@ class DBMigrateV3Config(migration.DBMigration):
                 'runner': self.ap.provider_cfg.data['runner'],
             }
             pipeline_config['ai']['local-agent']['model'] = model_uuid
-            pipeline_config['ai']['local-agent']['max-round'] = self.ap.pipeline_cfg.data['msg-truncate']['round'][
-                'max-round'
-            ]
 
             pipeline_config['ai']['local-agent']['prompt'] = [
                 {

src/langbot/pkg/pipeline/msgtrun/msgtrun.py

@@ -1,39 +0,0 @@
-from __future__ import annotations
-
-from .. import stage, entities
-from . import truncator
-from ...utils import importutil
-from ...agent.runner.config_migration import ConfigMigration
-import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
-from . import truncators
-
-importutil.import_modules_in_pkg(truncators)
-
-
-@stage.stage_class('ConversationMessageTruncator')
-class ConversationMessageTruncator(stage.PipelineStage):
-    """Conversation message truncator
-
-    Used to truncate the conversation message chain to adapt to the LLM message length limit.
-    """
-
-    trun: truncator.Truncator
-
-    async def initialize(self, pipeline_config: dict):
-        use_method = 'round'
-
-        for trun in truncator.preregistered_truncators:
-            if trun.name == use_method:
-                self.trun = trun(self.ap)
-                break
-        else:
-            raise ValueError(f'Unknown truncator: {use_method}')
-
-    async def process(self, query: pipeline_query.Query, stage_inst_name: str) -> entities.StageProcessResult:
-        """处理"""
-        if ConfigMigration.resolve_runner_id(query.pipeline_config):
-            return entities.StageProcessResult(result_type=entities.ResultType.CONTINUE, new_query=query)
-
-        query = await self.trun.truncate(query)
-
-        return entities.StageProcessResult(result_type=entities.ResultType.CONTINUE, new_query=query)

src/langbot/pkg/pipeline/msgtrun/round_policy.py

@@ -1,34 +0,0 @@
-"""Shared max-round message window helpers for Pipeline behavior."""
-from __future__ import annotations
-
-import typing
-
-
-DEFAULT_MAX_ROUND = 10
-
-
-def get_max_round(config: dict[str, typing.Any]) -> typing.Any:
-    """Return the configured Pipeline max-round value."""
-    return config.get('max-round', DEFAULT_MAX_ROUND)
-
-
-def select_max_round_messages(
-    messages: list[typing.Any] | None,
-    max_round: typing.Any,
-) -> list[typing.Any]:
-    """Select a bounded recent message window by user-round count."""
-    if not messages:
-        return []
-
-    temp_messages: list[typing.Any] = []
-    current_round = 0
-
-    for msg in messages[::-1]:
-        if current_round < max_round:
-            temp_messages.append(msg)
-            if getattr(msg, 'role', None) == 'user':
-                current_round += 1
-        else:
-            break
-
-    return temp_messages[::-1]

src/langbot/pkg/pipeline/msgtrun/truncator.py

@@ -1,56 +0,0 @@
-from __future__ import annotations
-
-import typing
-import abc
-
-from ...core import app
-import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
-
-preregistered_truncators: list[typing.Type[Truncator]] = []
-
-
-def truncator_class(
-    name: str,
-) -> typing.Callable[[typing.Type[Truncator]], typing.Type[Truncator]]:
-    """截断器类装饰器
-
-    Args:
-        name (str): 截断器名称
-
-    Returns:
-        typing.Callable[[typing.Type[Truncator]], typing.Type[Truncator]]: 装饰器
-    """
-
-    def decorator(cls: typing.Type[Truncator]) -> typing.Type[Truncator]:
-        assert issubclass(cls, Truncator)
-
-        cls.name = name
-
-        preregistered_truncators.append(cls)
-
-        return cls
-
-    return decorator
-
-
-class Truncator(abc.ABC):
-    """消息截断器基类"""
-
-    name: str
-
-    ap: app.Application
-
-    def __init__(self, ap: app.Application):
-        self.ap = ap
-
-    async def initialize(self):
-        pass
-
-    @abc.abstractmethod
-    async def truncate(self, query: pipeline_query.Query) -> pipeline_query.Query:
-        """截断
-
-        一般只需要操作query.messages，也可以扩展操作query.prompt, query.user_message。
-        请勿操作其他字段。
-        """
-        pass

src/langbot/pkg/pipeline/msgtrun/truncators/round.py

@@ -1,29 +0,0 @@
-from __future__ import annotations
-
-from .. import truncator
-import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
-from ....agent.runner.config_migration import ConfigMigration
-from ..round_policy import (
-    get_max_round,
-    select_max_round_messages,
-)
-
-
-@truncator.truncator_class('round')
-class RoundTruncator(truncator.Truncator):
-    """Truncate the conversation message chain to adapt to the LLM message length limit."""
-
-    async def truncate(self, query: pipeline_query.Query) -> pipeline_query.Query:
-        """截断"""
-        runner_id = ConfigMigration.resolve_runner_id(query.pipeline_config)
-        if runner_id:
-            runner_config = ConfigMigration.resolve_runner_config(query.pipeline_config, runner_id)
-        else:
-            runner_config = query.pipeline_config.get('msg-truncate', {}).get('round', {})
-
-        query.messages = select_max_round_messages(
-            query.messages,
-            get_max_round(runner_config),
-        )
-
-        return query

src/langbot/pkg/pipeline/pipelinemgr.py

@@ -28,7 +28,6 @@ from . import (
     wrapper,
     preproc,
     ratelimit,
-    msgtrun,
 )
 
 importutil.import_modules_in_pkgs(
@@ -42,7 +41,6 @@ importutil.import_modules_in_pkgs(
         wrapper,
         preproc,
         ratelimit,
-        msgtrun,
     ]
 )
 
@@ -438,6 +436,9 @@ class PipelineManager:
         # initialize stage containers according to pipeline_entity.stages
         stage_containers: list[StageInstContainer] = []
         for stage_name in pipeline_entity.stages:
+            if stage_name not in self.stage_dict:
+                self.ap.logger.warning(f'Pipeline stage {stage_name} is not registered; skipping')
+                continue
             stage_containers.append(StageInstContainer(inst_name=stage_name, inst=self.stage_dict[stage_name](self.ap)))
 
         for stage_container in stage_containers:

src/langbot/templates/legacy/pipeline.json

@@ -34,11 +34,5 @@
                 "limit": 60
             }
         }
-    },
-    "msg-truncate": {
-        "method": "round",
-        "round": {
-            "max-round": 10
-        }
     }
-}
+}

tests/unit_tests/agent/test_config_migration.py

@@ -120,7 +120,7 @@ class TestResolveRunnerConfig:
                 'runner_config': {
                     'plugin:langbot/local-agent/default': {
                         'model': 'uuid-123',
-                        'max_round': 10,
+                        'custom_option': 10,
                     },
                 },
             },
@@ -130,7 +130,7 @@ class TestResolveRunnerConfig:
             pipeline_config,
             'plugin:langbot/local-agent/default',
         )
-        assert config == {'model': 'uuid-123', 'max_round': 10}
+        assert config == {'model': 'uuid-123', 'custom_option': 10}
 
     def test_resolve_old_format_config(self):
         """Runtime config resolver should not read old format."""
@@ -138,7 +138,7 @@ class TestResolveRunnerConfig:
             'ai': {
                 'local-agent': {
                     'model': 'uuid-123',
-                    'max_round': 10,
+                    'custom_option': 10,
                 },
             },
         }
@@ -155,7 +155,7 @@ class TestResolveRunnerConfig:
             'ai': {
                 'local-agent': {
                     'model': 'uuid-123',
-                    'max_round': 10,
+                    'custom_option': 10,
                     'knowledge-base': 'kb-123',
                 },
             },
@@ -165,7 +165,7 @@ class TestResolveRunnerConfig:
             pipeline_config,
             'plugin:langbot/local-agent/default',
         )
-        assert config == {'model': 'uuid-123', 'max_round': 10, 'knowledge-bases': ['kb-123']}
+        assert config == {'model': 'uuid-123', 'custom_option': 10, 'knowledge-bases': ['kb-123']}
         assert 'knowledge-base' not in config
 
     def test_resolve_no_config(self):

tests/unit_tests/agent/test_config_migration_full.py

@@ -20,7 +20,6 @@ class TestMigratePipelineConfig:
                 },
                 'local-agent': {
                     'model': {'primary': 'model-uuid', 'fallbacks': []},
-                    'max-round': 10,
                     'knowledge-base': 'kb-uuid',
                     'prompt': [{'role': 'system', 'content': 'Hello'}],
                 },
@@ -35,9 +34,9 @@ class TestMigratePipelineConfig:
 
         # Config should be in runner_config
         assert 'plugin:langbot/local-agent/default' in migrated['ai']['runner_config']
-        assert migrated['ai']['runner_config']['plugin:langbot/local-agent/default']['max-round'] == 10
         assert migrated['ai']['runner_config']['plugin:langbot/local-agent/default']['knowledge-bases'] == ['kb-uuid']
         assert 'knowledge-base' not in migrated['ai']['runner_config']['plugin:langbot/local-agent/default']
+        assert 'max-round' not in migrated['ai']['runner_config']['plugin:langbot/local-agent/default']
 
         # Expire-time preserved
         assert migrated['ai']['runner']['expire-time'] == 0
@@ -76,7 +75,7 @@ class TestMigratePipelineConfig:
                 'runner_config': {
                     'plugin:langbot/local-agent/default': {
                         'model': {'primary': '', 'fallbacks': []},
-                        'max-round': 10,
+                        'custom-option': 10,
                     },
                 },
             },
@@ -86,7 +85,7 @@ class TestMigratePipelineConfig:
 
         # Should remain unchanged
         assert migrated['ai']['runner']['id'] == 'plugin:langbot/local-agent/default'
-        assert migrated['ai']['runner_config']['plugin:langbot/local-agent/default']['max-round'] == 10
+        assert migrated['ai']['runner_config']['plugin:langbot/local-agent/default']['custom-option'] == 10
 
     def test_new_format_local_agent_config_normalizes_legacy_kb_key(self):
         """Migration should normalize legacy KB aliases before runtime."""
@@ -260,18 +259,18 @@ class TestResolveRunnerConfig:
         config = {
             'ai': {
                 'runner_config': {
-                    'plugin:langbot/local-agent/default': {'max-round': 20},
+                    'plugin:langbot/local-agent/default': {'custom-option': 20},
                 },
             },
         }
         runner_config = ConfigMigration.resolve_runner_config(config, 'plugin:langbot/local-agent/default')
-        assert runner_config['max-round'] == 20
+        assert runner_config['custom-option'] == 20
 
     def test_resolve_old_format_config(self):
         """resolve_runner_config should not read old ai.local-agent at runtime."""
         config = {
             'ai': {
-                'local-agent': {'max-round': 15},
+                'local-agent': {'max-round': 15, 'custom-option': 20},
             },
         }
         runner_config = ConfigMigration.resolve_runner_config(config, 'plugin:langbot/local-agent/default')
@@ -281,21 +280,21 @@ class TestResolveRunnerConfig:
         """resolve_legacy_runner_config should read old ai.local-agent for migration."""
         config = {
             'ai': {
-                'local-agent': {'max-round': 15},
+                'local-agent': {'max-round': 15, 'custom-option': 20},
             },
         }
         runner_config = ConfigMigration.resolve_legacy_runner_config(config, 'plugin:langbot/local-agent/default')
-        assert runner_config['max-round'] == 15
+        assert runner_config == {'custom-option': 20}
 
     def test_resolve_new_format_priority(self):
         """New format runner_config should take priority."""
         config = {
             'ai': {
                 'runner_config': {
-                    'plugin:langbot/local-agent/default': {'max-round': 25},
+                    'plugin:langbot/local-agent/default': {'custom-option': 25},
                 },
-                'local-agent': {'max-round': 10},  # Old, should be ignored
+                'local-agent': {'max-round': 10, 'custom-option': 10},  # Old, should be ignored
             },
         }
         runner_config = ConfigMigration.resolve_runner_config(config, 'plugin:langbot/local-agent/default')
-        assert runner_config['max-round'] == 25
+        assert runner_config['custom-option'] == 25

tests/unit_tests/agent/test_event_first_protocol.py

@@ -4,7 +4,7 @@ Tests cover:
 1. Pipeline Query -> AgentEventEnvelope conversion
 2. Pipeline config -> AgentBinding conversion
 3. AgentRunContext not inlining full history by default
-4. Pipeline max-round only affecting bootstrap/adapter context
+4. LangBot Host not defining context-window controls
 5. Event-first run() entry point
 """
 from __future__ import annotations
@@ -147,23 +147,13 @@ class TestPipelineConfigToBinding:
         assert binding.scope.scope_type == "pipeline"
         assert binding.scope.scope_id == mock_query.pipeline_uuid
 
-    def test_config_to_binding_max_round(self, mock_query_with_max_round):
+    def test_config_to_binding_does_not_add_host_context_window(self, mock_query):
-        """Test max_round extraction for Pipeline adapter."""
+        """Pipeline binding should not define Host-side context window controls."""
-        binding = PipelineAdapter.pipeline_config_to_binding(
-            mock_query_with_max_round, "plugin:test/plugin/runner"
-        )
-
-        # max_round should be captured but NOT in Protocol v1 entities
-        assert binding.max_round == 10
-
-    def test_config_to_binding_no_max_round(self, mock_query):
-        """Test binding without max_round."""
         binding = PipelineAdapter.pipeline_config_to_binding(
             mock_query, "plugin:test/plugin/runner"
         )
 
-        # max_round may be None
+        assert not hasattr(binding, "max_round")
-        assert binding.max_round is None
 
 
 class TestAgentRunContextProtocolV1:
@@ -248,60 +238,23 @@ class TestAgentRunContextProtocolV1:
         assert ctx.bootstrap is None or isinstance(ctx.bootstrap.messages, list)
 
 
-class TestMaxRoundNotInProtocol:
+class TestHostContextWindowNotInProtocol:
-    """Test that Pipeline max-round only affects adapter context, not Protocol v1."""
+    """Test that Host-side context window controls are not in Protocol v1."""
 
-    def test_max_round_not_in_sdk_context(self):
+    def test_context_window_not_in_sdk_context(self):
-        """Test max-round is not a field in SDK AgentRunContext."""
+        """AgentRunContext should not expose Host-side window controls."""
-        # AgentRunContext should not have max_round field
         ctx_fields = AgentRunContext.model_fields.keys()
 
         assert "max_round" not in ctx_fields
         assert "maxRound" not in ctx_fields
 
-    def test_max_round_in_adapter_context(self):
+    def test_binding_has_no_context_window_field(self, mock_query):
-        """Test max_round is in adapter context, not main context."""
+        """Pipeline adapter should not attach context window policy to binding."""
-        trigger = AgentTrigger(type="message.received")
-        event = AgentEventContext(
-            event_id="evt_1",
-            event_type="message.received",
-            source="platform",
-        )
-        input = AgentInput(text="Hello")
-        from langbot_plugin.api.entities.builtin.agent_runner.resources import AgentResources
-        from langbot_plugin.api.entities.builtin.agent_runner.runtime import AgentRuntimeContext
-        from langbot_plugin.api.entities.builtin.agent_runner.delivery import DeliveryContext
-        from langbot_plugin.api.entities.builtin.agent_runner.context import AdapterContext
-
-        adapter = AdapterContext(max_round=10)
-
-        ctx = AgentRunContext(
-            run_id="run_1",
-            trigger=trigger,
-            event=event,
-            input=input,
-            delivery=DeliveryContext(surface="platform"),
-            resources=AgentResources(),
-            runtime=AgentRuntimeContext(),
-            adapter=adapter,
-        )
-
-        # max_round is in adapter context, not main context
-        assert ctx.adapter is not None
-        assert ctx.adapter.max_round == 10
-
-    def test_binding_max_round_for_adapter_only(self, mock_query_with_max_round):
-        """Test max_round in binding is for adapter use, not Protocol v1."""
         binding = PipelineAdapter.pipeline_config_to_binding(
-            mock_query_with_max_round, "plugin:test/plugin/runner"
+            mock_query, "plugin:test/plugin/runner"
         )
 
-        # max_round is in binding (Host-internal) for Pipeline adapter
+        assert not hasattr(binding, "max_round")
-        assert binding.max_round == 10
-
-        # But SDK entities don't have it
-        ctx_fields = AgentRunContext.model_fields.keys()
-        assert "max_round" not in ctx_fields
 
 
 class TestSDKCapabilitiesProtocolV1:
@@ -416,18 +369,6 @@ def mock_query():
     return query
 
 
-@pytest.fixture
-def mock_query_with_max_round(mock_query):
-    """Create a mock Query with max_round configuration."""
-    mock_query.pipeline_config = {
-        "ai": {
-            "runner": "plugin:test/plugin/runner",
-            "max-round": 10,
-        }
-    }
-    return mock_query
-
-
 @pytest.fixture
 def mock_query_no_session():
     """Create a mock Query without session."""

tests/unit_tests/agent/test_orchestrator_integration.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 import asyncio
 import datetime
 import types
-from unittest.mock import AsyncMock, MagicMock
+from unittest.mock import AsyncMock
 
 import pytest
 from sqlalchemy.ext.asyncio import create_async_engine, AsyncEngine
@@ -332,8 +332,8 @@ async def test_orchestrator_runs_fake_plugin_with_authorized_context(clean_agent
 
 
 @pytest.mark.asyncio
-async def test_orchestrator_packages_max_round_without_mutating_query(clean_agent_state):
+async def test_orchestrator_does_not_package_query_messages_into_context(clean_agent_state):
-    """Test that max-round is packaged without mutating original query."""
+    """Host should not build an agent working-context window from query.messages."""
     db_engine = clean_agent_state
     descriptor = make_descriptor()
     plugin_connector = FakePluginConnector(
@@ -347,7 +347,7 @@ async def test_orchestrator_packages_max_round_without_mutating_query(clean_agen
     ap = FakeApplication(plugin_connector, db_engine)
     orchestrator = AgentRunOrchestrator(ap, FakeRegistry(descriptor))
     query = make_query()
-    query.pipeline_config["ai"]["runner_config"][RUNNER_ID]["max-round"] = 2
+    query.pipeline_config["ai"]["runner_config"][RUNNER_ID]["agent-window"] = 2
     query.messages = [
         provider_message.Message(role="user", content="message 1"),
         provider_message.Message(role="assistant", content="response 1"),
@@ -361,21 +361,10 @@ async def test_orchestrator_packages_max_round_without_mutating_query(clean_agen
 
     assert len(messages) == 1
     context = plugin_connector.contexts[0]
-    # Protocol v1: messages are in bootstrap.messages
+    assert context["config"]["agent-window"] == 2
-    assert context["bootstrap"] is not None
+    assert context["bootstrap"] is None
-    assert [message["content"] for message in context["bootstrap"]["messages"]] == [
+    assert "adapter_messages" not in context["adapter"]
-        "message 2",
+    assert "context_packaging" not in context["runtime"]["metadata"]
-        "response 2",
-        "message 3",
-        "response 3",
-    ]
-    # Also exposed in adapter.adapter_messages for runners that consume adapter bootstrap.
-    assert [message["content"] for message in context["adapter"]["adapter_messages"]] == [
-        "message 2",
-        "response 2",
-        "message 3",
-        "response 3",
-    ]
     assert [message.content for message in query.messages] == [
         "message 1",
         "response 1",
@@ -384,18 +373,6 @@ async def test_orchestrator_packages_max_round_without_mutating_query(clean_agen
         "message 3",
         "response 3",
     ]
-    assert context["runtime"]["metadata"]["context_packaging"] == {
-        "policy": {
-            "mode": "max_round",
-            "max_round": 2,
-        },
-        "history": {
-            "source": "query.messages",
-            "source_total_count": 6,
-            "delivered_count": 4,
-            "messages_complete": False,
-        },
-    }
 
 
 @pytest.mark.asyncio
@@ -493,7 +470,7 @@ async def test_orchestrator_enforces_total_runner_deadline(clean_agent_state):
 
     assert exc_info.value.retryable is True
     assert "runner.timeout" in str(exc_info.value)
-    assert await get_session_registry().get(plugin_connector.contexts[0]["run_id"]) is None
+    assert await get_session_registry().list_active_runs() == []
 
 
 class TestPipelineCompatibilityQueryIdInSession:
@@ -610,7 +587,7 @@ class TestPipelineAdapterPromptAndParams:
             ],
         )
 
-        messages = [message async for message in orchestrator.run_from_query(query)]
+        _messages = [message async for message in orchestrator.run_from_query(query)]
 
         context = plugin_connector.contexts[0]
         # Prompt should be in adapter.extra
@@ -641,7 +618,7 @@ class TestPipelineAdapterPromptAndParams:
             "another_param": 123,
         }
 
-        messages = [message async for message in orchestrator.run_from_query(query)]
+        _messages = [message async for message in orchestrator.run_from_query(query)]
 
         context = plugin_connector.contexts[0]
         assert context["adapter"]["extra"]["params"] == {
@@ -671,7 +648,7 @@ class TestPipelineAdapterPromptAndParams:
             "_pipeline_bound_plugins": ["plugin1"],
         }
 
-        messages = [message async for message in orchestrator.run_from_query(query)]
+        _messages = [message async for message in orchestrator.run_from_query(query)]
 
         context = plugin_connector.contexts[0]
         params = context["adapter"]["extra"]["params"]
@@ -703,7 +680,7 @@ class TestPipelineAdapterPromptAndParams:
             "credential": "secret000",
         }
 
-        messages = [message async for message in orchestrator.run_from_query(query)]
+        _messages = [message async for message in orchestrator.run_from_query(query)]
 
         context = plugin_connector.contexts[0]
         params = context["adapter"]["extra"]["params"]
@@ -735,7 +712,7 @@ class TestPipelineAdapterPromptAndParams:
             "a_lambda": lambda x: x,  # function is not JSON-serializable
         }
 
-        messages = [message async for message in orchestrator.run_from_query(query)]
+        _messages = [message async for message in orchestrator.run_from_query(query)]
 
         context = plugin_connector.contexts[0]
         params = context["adapter"]["extra"]["params"]

tests/unit_tests/pipeline/test_msgtrun.py

@@ -1,369 +0,0 @@
-"""
-Unit tests for ConversationMessageTruncator (msgtrun) pipeline stage.
-
-Tests cover:
-- Normal truncation behavior based on max-round
-- Boundary length handling
-- Empty message handling
-- Multi-message chain truncation
-"""
-
-from __future__ import annotations
-
-import pytest
-from importlib import import_module
-
-from tests.factories import (
-    FakeApp,
-    text_query,
-)
-
-import langbot_plugin.api.entities.builtin.provider.message as provider_message
-
-
-RUNNER_ID = 'plugin:langbot/local-agent/default'
-
-
-def get_msgtrun_module():
-    """Lazy import to avoid circular import issues."""
-    # Import pipelinemgr first to trigger stage registration
-    import_module('langbot.pkg.pipeline.pipelinemgr')
-    return import_module('langbot.pkg.pipeline.msgtrun.msgtrun')
-
-
-def get_truncator_module():
-    """Lazy import for truncator base."""
-    return import_module('langbot.pkg.pipeline.msgtrun.truncator')
-
-
-def get_entities_module():
-    """Lazy import for pipeline entities."""
-    return import_module('langbot.pkg.pipeline.entities')
-
-
-def get_round_truncator_module():
-    """Lazy import for round truncator."""
-    return import_module('langbot.pkg.pipeline.msgtrun.truncators.round')
-
-
-def make_truncate_config(max_round: int = 5):
-    """Create a pipeline config with max-round setting."""
-    return {
-        'msg-truncate': {
-            'method': 'round',
-            'round': {
-                'max-round': max_round,
-            },
-        },
-    }
-
-
-def make_agent_runner_config(max_round: int = 5):
-    """Create an AgentRunner pipeline config with max-round binding config."""
-    return {
-        'ai': {
-            'runner': {'id': RUNNER_ID},
-            'runner_config': {
-                RUNNER_ID: {
-                    'max-round': max_round,
-                },
-            },
-        }
-    }
-
-
-class TestConversationMessageTruncatorInit:
-    """Tests for ConversationMessageTruncator initialization."""
-
-    @pytest.mark.asyncio
-    async def test_initialize_round_truncator(self):
-        """Initialize should select 'round' truncator by default."""
-        msgtrun = get_msgtrun_module()
-        truncator = get_truncator_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config()
-
-        await stage.initialize(pipeline_config)
-
-        assert stage.trun is not None
-        assert isinstance(stage.trun, truncator.Truncator)
-
-    @pytest.mark.asyncio
-    async def test_initialize_unknown_truncator_raises(self):
-        """Initialize with unknown truncator method should raise ValueError."""
-        msgtrun = get_msgtrun_module()
-        truncator = get_truncator_module()
-
-        # Save original preregistered_truncators
-        original_truncators = truncator.preregistered_truncators.copy()
-
-        try:
-            # Clear registered truncators to simulate unknown method
-            truncator.preregistered_truncators = []
-
-            app = FakeApp()
-            stage = msgtrun.ConversationMessageTruncator(app)
-
-            pipeline_config = make_truncate_config()
-
-            with pytest.raises(ValueError, match='Unknown truncator'):
-                await stage.initialize(pipeline_config)
-        finally:
-            # Restore original truncators
-            truncator.preregistered_truncators = original_truncators
-
-
-class TestRoundTruncatorProcess:
-    """Tests for RoundTruncator truncation behavior."""
-
-    @pytest.mark.asyncio
-    async def test_truncate_within_limit(self):
-        """Messages within max-round limit should not be truncated."""
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config(max_round=5)
-
-        await stage.initialize(pipeline_config)
-
-        # Create query with 3 messages (within limit)
-        query = text_query("current message")
-        query.pipeline_config = pipeline_config
-        query.messages = [
-            provider_message.Message(role='user', content='message 1'),
-            provider_message.Message(role='assistant', content='response 1'),
-            provider_message.Message(role='user', content='message 2'),
-            provider_message.Message(role='assistant', content='response 2'),
-            provider_message.Message(role='user', content='current message'),
-        ]
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-        # All messages should be preserved
-        assert len(result.new_query.messages) == 5
-
-    @pytest.mark.asyncio
-    async def test_agent_runner_path_skips_pipeline_truncation(self):
-        """AgentRunner path should leave query.messages intact at pipeline stage."""
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_agent_runner_config(max_round=1)
-
-        await stage.initialize(pipeline_config)
-
-        query = text_query("current")
-        query.pipeline_config = pipeline_config
-        query.messages = [
-            provider_message.Message(role='user', content='old1'),
-            provider_message.Message(role='assistant', content='old1_resp'),
-            provider_message.Message(role='user', content='current'),
-        ]
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-        assert [(msg.role, msg.content) for msg in result.new_query.messages] == [
-            ('user', 'old1'),
-            ('assistant', 'old1_resp'),
-            ('user', 'current'),
-        ]
-
-    @pytest.mark.asyncio
-    async def test_truncate_exceeds_limit(self):
-        """Messages exceeding max-round should be truncated precisely.
-
-        Algorithm: traverse backwards, collect while current_round < max_round, count user messages as rounds.
-        For max_round=2 with 7 messages (u1, a1, u2, a2, u3, a3, u_current):
-        - Iterate: u_current(r=0<2, collect, r=1), a3(r=1<2, collect), u3(r=1<2, collect, r=2)
-        - a2: r=2 not < 2 → break
-        - Collected reverse: [u_current, a3, u3]
-        - Reversed: [u3, a3, u_current] = 3 messages
-        """
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config(max_round=2)  # Only keep 2 rounds
-
-        await stage.initialize(pipeline_config)
-
-        # Create query with many messages exceeding limit
-        # 7 messages = 3 full rounds + 1 current user
-        query = text_query("current message")
-        query.pipeline_config = pipeline_config
-        query.messages = [
-            provider_message.Message(role='user', content='message 1'),
-            provider_message.Message(role='assistant', content='response 1'),
-            provider_message.Message(role='user', content='message 2'),
-            provider_message.Message(role='assistant', content='response 2'),
-            provider_message.Message(role='user', content='message 3'),
-            provider_message.Message(role='assistant', content='response 3'),
-            provider_message.Message(role='user', content='current message'),
-        ]
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-        # Should keep exactly 3 messages: message3, response3, current message
-        messages = result.new_query.messages
-        assert len(messages) == 3
-
-        # Verify exact message content
-        assert messages[0].role == 'user'
-        assert messages[0].content == 'message 3'
-        assert messages[1].role == 'assistant'
-        assert messages[1].content == 'response 3'
-        assert messages[2].role == 'user'
-        assert messages[2].content == 'current message'
-
-    @pytest.mark.asyncio
-    async def test_truncate_empty_messages(self):
-        """Empty messages list should return empty list."""
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config()
-
-        await stage.initialize(pipeline_config)
-
-        query = text_query("hello")
-        query.pipeline_config = pipeline_config
-        query.messages = []
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-        assert len(result.new_query.messages) == 0
-
-    @pytest.mark.asyncio
-    async def test_truncate_single_message(self):
-        """Single message should be preserved."""
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config()
-
-        await stage.initialize(pipeline_config)
-
-        query = text_query("hello")
-        query.pipeline_config = pipeline_config
-        query.messages = [
-            provider_message.Message(role='user', content='hello'),
-        ]
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-        assert len(result.new_query.messages) == 1
-
-    @pytest.mark.asyncio
-    async def test_truncate_preserves_order(self):
-        """Truncation should preserve message order."""
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config(max_round=2)
-
-        await stage.initialize(pipeline_config)
-
-        query = text_query("current")
-        query.pipeline_config = pipeline_config
-        query.messages = [
-            provider_message.Message(role='user', content='user1'),
-            provider_message.Message(role='assistant', content='asst1'),
-            provider_message.Message(role='user', content='user2'),
-            provider_message.Message(role='assistant', content='asst2'),
-            provider_message.Message(role='user', content='user3'),
-        ]
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-
-        messages = result.new_query.messages
-        assert [(msg.role, msg.content) for msg in messages] == [
-            ('user', 'user2'),
-            ('assistant', 'asst2'),
-            ('user', 'user3'),
-        ]
-
-    @pytest.mark.asyncio
-    async def test_truncate_max_round_one(self):
-        """max-round=1 should only keep last user message."""
-        msgtrun = get_msgtrun_module()
-        entities = get_entities_module()
-
-        app = FakeApp()
-        stage = msgtrun.ConversationMessageTruncator(app)
-
-        pipeline_config = make_truncate_config(max_round=1)
-
-        await stage.initialize(pipeline_config)
-
-        query = text_query("current")
-        query.pipeline_config = pipeline_config
-        query.messages = [
-            provider_message.Message(role='user', content='old1'),
-            provider_message.Message(role='assistant', content='old1_resp'),
-            provider_message.Message(role='user', content='current'),
-        ]
-
-        result = await stage.process(query, 'ConversationMessageTruncator')
-
-        assert result.result_type == entities.ResultType.CONTINUE
-        messages = result.new_query.messages
-        assert [(msg.role, msg.content) for msg in messages] == [('user', 'current')]
-
-
-class TestRoundTruncatorDirect:
-    """Direct tests for RoundTruncator class."""
-
-    @pytest.mark.asyncio
-    async def test_round_truncator_direct_process(self):
-        """Test RoundTruncator truncate method directly."""
-        truncator_mod = get_truncator_module()
-
-        app = FakeApp()
-
-        # Get the RoundTruncator class from preregistered
-        for trun_cls in truncator_mod.preregistered_truncators:
-            if trun_cls.name == 'round':
-                trun = trun_cls(app)
-                break
-
-        query = text_query("hello")
-        query.pipeline_config = make_truncate_config(max_round=3)
-        query.messages = [
-            provider_message.Message(role='user', content='m1'),
-            provider_message.Message(role='assistant', content='r1'),
-            provider_message.Message(role='user', content='m2'),
-            provider_message.Message(role='assistant', content='r2'),
-            provider_message.Message(role='user', content='hello'),
-        ]
-
-        result = await trun.truncate(query)
-
-        assert result is not None
-        assert hasattr(result, 'messages')