diff --git a/app/harness/__init__.py b/app/harness/__init__.py
index e69de29..5ec5abc 100644
--- a/app/harness/__init__.py
+++ b/app/harness/__init__.py
@@ -0,0 +1,36 @@
+"""app/harness/ — 训练循环编排层。
+
+组合 core/evolution/（决策内核）+ core/agent/（AgentLoop）+ adapters/（LLM/VLM/telemetry），
+实现自进化闭环的训练循环三级嵌套、块序贯验证、快慢双速进化、checkpoint/resume。
+"""
+
+from app.harness.config import RunConfig, load_config
+from app.harness.inference import InferenceResult, run_inference
+from app.harness.log import HarnessLog, RunLogImpl
+from app.harness.pools import Pools, build_or_load_pools, build_pools, load_pools, save_pools
+from app.harness.runner import Runner
+from app.harness.workspace import (
+    ResolvedPaths,
+    VersionedPromptStore,
+    VersionedSkillStore,
+    resolve_paths,
+)
+
+__all__ = [
+    "HarnessLog",
+    "InferenceResult",
+    "Pools",
+    "ResolvedPaths",
+    "RunConfig",
+    "RunLogImpl",
+    "Runner",
+    "VersionedPromptStore",
+    "VersionedSkillStore",
+    "build_or_load_pools",
+    "build_pools",
+    "load_config",
+    "load_pools",
+    "resolve_paths",
+    "run_inference",
+    "save_pools",
+]
diff --git a/app/harness/checkpoint.py b/app/harness/checkpoint.py
index e389546..d08b0a5 100644
--- a/app/harness/checkpoint.py
+++ b/app/harness/checkpoint.py
@@ -14,9 +14,10 @@ from __future__ import annotations
 
 import json
 import os
-from dataclasses import asdict, dataclass, field
+from dataclasses import asdict
 from typing import TYPE_CHECKING, Any
 
+from app.harness.validate import Probation
 from core.evolution.types import (
     CaseSample,
     RejectedEdit,
@@ -29,10 +30,6 @@ if TYPE_CHECKING:
 
 CHECKPOINT_SCHEMA_VERSION = 1
 
-
-from app.harness.validate import Probation  # noqa: E402
-
-
 # ---------------------------------------------------------------------------
 # 结构性 / 决策性指纹键
 # ---------------------------------------------------------------------------