diff --git a/core/executor_docker.py b/core/executor_docker.py
index 0e36662..41f40ed 100644
--- a/core/executor_docker.py
+++ b/core/executor_docker.py
@@ -47,13 +47,13 @@ import json
 # canceller 侧线程 poll cancel_check 的间隔;单测可 patch 此常量加速
 _CANCEL_POLL_INTERVAL_S = 0.2
 
-from tools.base import format_timeout_result
+from tools.output import format_timeout_result
 
 from .executor import ExecCtx, Executor, ToolResult
 from .executor_host import HostExecutor
 from .pysyntax import precheck_python
 from .sandbox import SandboxPool
-from tools.base import compact_tool_output
+from tools.output import compact_tool_output
 
 
 # write/edit 走配额 gate;read/glob/grep 不消耗磁盘,放行
diff --git a/tests/test_timeout_partial.py b/tests/test_timeout_partial.py
index de394ed..de49935 100644
--- a/tests/test_timeout_partial.py
+++ b/tests/test_timeout_partial.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 import tempfile
 import unittest
 
-from tools.base import format_timeout_result
+from tools.output import format_timeout_result
 from tools.run_python import RunPythonTool
 
 
diff --git a/tests/test_tool_output_compaction.py b/tests/test_tool_output_compaction.py
index 1602ebd..01a1834 100644
--- a/tests/test_tool_output_compaction.py
+++ b/tests/test_tool_output_compaction.py
@@ -1,7 +1,7 @@
 import unittest
 import tempfile
 
-from tools.base import compact_tool_output
+from tools.output import compact_tool_output
 from tools.run_python import RunPythonTool
 
 
diff --git a/tools/base.py b/tools/base.py
index 2f91162..22ed1bb 100644
--- a/tools/base.py
+++ b/tools/base.py
@@ -16,52 +16,6 @@ class FileOutOfBounds(Exception):
     """agent 给的文件路径解析后落在 user_root 之外(防 `../` 读到别人/系统文件)。"""
 
 
-def compact_tool_output(
-    text: str,
-    *,
-    max_chars: int = 8_000,
-    head_chars: int = 4_000,
-    tail_chars: int = 2_000,
-) -> str:
-    """压缩长工具输出,保留头尾和截断说明。"""
-    if len(text) <= max_chars:
-        return text
-    head_chars = max(0, min(head_chars, max_chars))
-    tail_chars = max(0, min(tail_chars, max_chars - head_chars))
-    removed = len(text) - head_chars - tail_chars
-    return (
-        text[:head_chars]
-        + f"\n[... truncated, {removed} chars omitted ...]\n"
-        + (text[-tail_chars:] if tail_chars else "")
-    )
-
-
-_TIMEOUT_HINT = (
-    "若是批量循环(检索 / PDF 抽取 / 下载等):① 据上面已完成的部分**续跑剩下的**,别整批重跑;"
-    "② 每完成一项就落盘 / 打印进度,超时也不丢;③ 大批量 / 大下载改用 background=true 后台跑,"
-    "再用 check_process 取结果;④ 单次别塞太多项。"
-)
-
-
-def format_timeout_result(stdout: str, stderr: str, timeout_s: int) -> str:
-    """run_python / shell 超时结果:带上超时前已捕获的部分输出 + 续跑提示。
-
-    进程被 kill 前跑出的 stdout/stderr 本已捕获(subprocess 标准行为:TimeoutExpired
-    带 .stdout/.stderr、docker 路径 kill 后 communicate() 续读),旧实现直接丢弃只回一句
-    超时 → 模型看不到「跑到哪了」、整批重来(工具失败面板 #8:批量检索 / PDF 抽取 / 下载
-    超时反复重跑,累计最多)。这里把部分输出一并返回,让模型据此续跑未完成的。"""
-    parts = []
-    if stdout and stdout.strip():
-        parts.append(f"[stdout]\n{stdout.rstrip()}")
-    if stderr and stderr.strip():
-        parts.append(f"[stderr]\n{stderr.rstrip()}")
-    parts.append(
-        f"[Error] command timed out after {timeout_s}s(进程已被杀,上方为超时前的部分输出)。"
-    )
-    parts.append(_TIMEOUT_HINT)
-    return "\n".join(parts)
-
-
 class Tool(ABC):
     name: str = ""
     description: str = ""
diff --git a/tools/check_process.py b/tools/check_process.py
index 7e1f858..86188ef 100644
--- a/tools/check_process.py
+++ b/tools/check_process.py
@@ -12,7 +12,8 @@ from typing import Optional
 
 from core import procs
 
-from .base import Tool, compact_tool_output
+from .base import Tool
+from .output import compact_tool_output
 
 
 class CheckProcessTool(Tool):
diff --git a/tools/look_at_image.py b/tools/look_at_image.py
index bf784d4..3b69a10 100644
--- a/tools/look_at_image.py
+++ b/tools/look_at_image.py
@@ -16,7 +16,8 @@ from uuid import UUID
 from core.ark_client import ArkConfig
 from core.storage.usage import record_vision_usage
 
-from .base import Tool, compact_tool_output
+from .base import Tool
+from .output import compact_tool_output
 from .image_ref import load_image_as_data_url
 from .media_common import ark_chat_with_retry, extract_chat_answer, record_usage_safe
 
diff --git a/tools/output.py b/tools/output.py
new file mode 100644
index 0000000..811241b
--- /dev/null
+++ b/tools/output.py
@@ -0,0 +1,48 @@
+"""工具输出处理原语(从 tools/base.py 析出,2026-07-23——base 只留 Tool 基类与路径边界)。"""
+from __future__ import annotations
+
+
+def compact_tool_output(
+    text: str,
+    *,
+    max_chars: int = 8_000,
+    head_chars: int = 4_000,
+    tail_chars: int = 2_000,
+) -> str:
+    """压缩长工具输出,保留头尾和截断说明。"""
+    if len(text) <= max_chars:
+        return text
+    head_chars = max(0, min(head_chars, max_chars))
+    tail_chars = max(0, min(tail_chars, max_chars - head_chars))
+    removed = len(text) - head_chars - tail_chars
+    return (
+        text[:head_chars]
+        + f"\n[... truncated, {removed} chars omitted ...]\n"
+        + (text[-tail_chars:] if tail_chars else "")
+    )
+
+
+_TIMEOUT_HINT = (
+    "若是批量循环(检索 / PDF 抽取 / 下载等):① 据上面已完成的部分**续跑剩下的**,别整批重跑;"
+    "② 每完成一项就落盘 / 打印进度,超时也不丢;③ 大批量 / 大下载改用 background=true 后台跑,"
+    "再用 check_process 取结果;④ 单次别塞太多项。"
+)
+
+
+def format_timeout_result(stdout: str, stderr: str, timeout_s: int) -> str:
+    """run_python / shell 超时结果:带上超时前已捕获的部分输出 + 续跑提示。
+
+    进程被 kill 前跑出的 stdout/stderr 本已捕获(subprocess 标准行为:TimeoutExpired
+    带 .stdout/.stderr、docker 路径 kill 后 communicate() 续读),旧实现直接丢弃只回一句
+    超时 → 模型看不到「跑到哪了」、整批重来(工具失败面板 #8:批量检索 / PDF 抽取 / 下载
+    超时反复重跑,累计最多)。这里把部分输出一并返回,让模型据此续跑未完成的。"""
+    parts = []
+    if stdout and stdout.strip():
+        parts.append(f"[stdout]\n{stdout.rstrip()}")
+    if stderr and stderr.strip():
+        parts.append(f"[stderr]\n{stderr.rstrip()}")
+    parts.append(
+        f"[Error] command timed out after {timeout_s}s(进程已被杀,上方为超时前的部分输出)。"
+    )
+    parts.append(_TIMEOUT_HINT)
+    return "\n".join(parts)
diff --git a/tools/read_document.py b/tools/read_document.py
index d61aad2..2155908 100644
--- a/tools/read_document.py
+++ b/tools/read_document.py
@@ -18,7 +18,8 @@ from uuid import UUID
 from core.ark_client import ArkConfig
 from core.storage.usage import record_vision_usage
 
-from .base import Tool, compact_tool_output
+from .base import Tool
+from .output import compact_tool_output
 from .image_ref import _CONTAINER_ROOT, load_pdf_as_data_url, resolve_in_root
 from .media_common import ark_chat_with_retry, extract_chat_answer, record_usage_safe
 
diff --git a/tools/run_python.py b/tools/run_python.py
index 27502ca..3adb8d3 100644
--- a/tools/run_python.py
+++ b/tools/run_python.py
@@ -18,7 +18,8 @@ from typing import Optional
 from core import procs
 from core.pysyntax import precheck_python
 
-from .base import Tool, compact_tool_output, format_timeout_result
+from .base import Tool
+from .output import compact_tool_output, format_timeout_result
 
 _SENSITIVE_PATTERNS = ("API_KEY", "TOKEN", "SECRET", "PASSWORD", "PRIVATE_KEY")
 # 刻意放行的例外:research skill 在 sandbox 里直连 paper_server,这把只读文献库 key
diff --git a/tools/shell.py b/tools/shell.py
index 964f05c..4bf16da 100644
--- a/tools/shell.py
+++ b/tools/shell.py
@@ -11,7 +11,8 @@ from typing import Optional
 
 from core import procs
 
-from .base import Tool, compact_tool_output
+from .base import Tool
+from .output import compact_tool_output
 
 
 class ShellTool(Tool):