From e7ed8601142152e62dd5db96c723da05306bec42 Mon Sep 17 00:00:00 2001
From: Aran Yogesh <yogesh.mahendran@langchain.dev>
Date: Mon, 23 Feb 2026 19:09:38 -0800
Subject: [PATCH] feat: enforce timeouts on execute tool commands (#955)

* feat: enforce timeouts on execute tool commands

* refactor: dedupe execute-timeout middleware logic

* cr

* move info to debug

---------

Co-authored-by: bracesproul <braceasproul@gmail.com>
---
 apps/agent/agent/middleware/__init__.py       |  2 +
 .../agent/middleware/timeout_execute_tool.py  | 83 +++++++++++++++++++
 apps/agent/agent/prompt.py                    |  2 +
 apps/agent/agent/server.py                    |  2 +
 4 files changed, 89 insertions(+)
 create mode 100644 apps/agent/agent/middleware/timeout_execute_tool.py

diff --git a/apps/agent/agent/middleware/__init__.py b/apps/agent/agent/middleware/__init__.py
index 250091d4..3e8253ac 100644
--- a/apps/agent/agent/middleware/__init__.py
+++ b/apps/agent/agent/middleware/__init__.py
@@ -1,9 +1,11 @@
 from .check_message_queue import check_message_queue_before_model
 from .open_pr import open_pr_if_needed
 from .post_to_linear import post_to_linear_after_model
+from .timeout_execute_tool import TimeoutExecuteToolMiddleware
 from .tool_error_handler import ToolErrorMiddleware
 
 __all__ = [
+    "TimeoutExecuteToolMiddleware",
     "ToolErrorMiddleware",
     "check_message_queue_before_model",
     "open_pr_if_needed",
diff --git a/apps/agent/agent/middleware/timeout_execute_tool.py b/apps/agent/agent/middleware/timeout_execute_tool.py
new file mode 100644
index 00000000..b51f597a
--- /dev/null
+++ b/apps/agent/agent/middleware/timeout_execute_tool.py
@@ -0,0 +1,83 @@
+"""Tool middleware that wraps execute commands with a timeout."""
+
+from __future__ import annotations
+
+import logging
+import re
+import shlex
+from collections.abc import Awaitable, Callable
+
+from langchain.agents.middleware.types import AgentMiddleware, AgentState
+from langchain_core.messages import ToolMessage
+from langgraph.prebuilt.tool_node import ToolCallRequest
+from langgraph.types import Command
+
+logger = logging.getLogger(__name__)
+
+DEFAULT_TIMEOUT_SECONDS = 300
+TIMEOUT_REGEX = re.compile(r"\btimeout\s+\d+(?:\.\d+)?\s*[smhd]?\b", re.IGNORECASE)
+
+
+def _get_tool_name(request: ToolCallRequest) -> str | None:
+    tool_call = request.tool_call
+    if isinstance(tool_call, dict):
+        return tool_call.get("name")
+    return None
+
+
+def _get_command_arg(request: ToolCallRequest) -> str | None:
+    tool_call = request.tool_call
+    if not isinstance(tool_call, dict):
+        return None
+    args = tool_call.get("args")
+    if not isinstance(args, dict):
+        return None
+    command = args.get("command")
+    return command if isinstance(command, str) else None
+
+
+def _wrap_command(command: str) -> str:
+    if TIMEOUT_REGEX.search(command):
+        return command
+    quoted = shlex.quote(command)
+    return f"timeout {DEFAULT_TIMEOUT_SECONDS}s sh -c {quoted}"
+
+
+def _overwrite_request_if_needed(request: ToolCallRequest) -> ToolCallRequest:
+    if _get_tool_name(request) != "execute":
+        return request
+
+    command = _get_command_arg(request)
+    if not command:
+        return request
+
+    wrapped = _wrap_command(command)
+    if wrapped == command:
+        return request
+
+    tool_call = dict(request.tool_call)
+    args = dict(tool_call.get("args", {}))
+    args["command"] = wrapped
+    tool_call["args"] = args
+    logger.debug("Wrapped execute command with timeout")
+    return request.override(tool_call=tool_call)
+
+
+class TimeoutExecuteToolMiddleware(AgentMiddleware):
+    """Ensure execute tool calls are wrapped with a timeout."""
+
+    state_schema = AgentState
+
+    def wrap_tool_call(
+        self,
+        request: ToolCallRequest,
+        handler: Callable[[ToolCallRequest], ToolMessage | Command],
+    ) -> ToolMessage | Command:
+        return handler(_overwrite_request_if_needed(request))
+
+    async def awrap_tool_call(
+        self,
+        request: ToolCallRequest,
+        handler: Callable[[ToolCallRequest], Awaitable[ToolMessage | Command]],
+    ) -> ToolMessage | Command:
+        return await handler(_overwrite_request_if_needed(request))
diff --git a/apps/agent/agent/prompt.py b/apps/agent/agent/prompt.py
index 85adab26..7f80740e 100644
--- a/apps/agent/agent/prompt.py
+++ b/apps/agent/agent/prompt.py
@@ -8,6 +8,8 @@ All code execution and file operations happen in this sandbox environment.
 
 **Important:**
 - Use `{working_dir}` as your working directory for all operations
+- The `execute` tool enforces a 5-minute timeout by default (`timeout 300s`)
+- If a command times out and needs longer, rerun it by explicitly appending `timeout Ns`
 
 
 ---
diff --git a/apps/agent/agent/server.py b/apps/agent/agent/server.py
index ea0bca67..ebb4a891 100644
--- a/apps/agent/agent/server.py
+++ b/apps/agent/agent/server.py
@@ -32,6 +32,7 @@ from .middleware import (
     check_message_queue_before_model,
     open_pr_if_needed,
     post_to_linear_after_model,
+    TimeoutExecuteToolMiddleware,
 )
 from .prompt import construct_system_prompt
 from .tools import commit_and_open_pr, fetch_url, http_request
@@ -345,6 +346,7 @@ async def get_agent(config: RunnableConfig) -> Pregel:  # noqa: PLR0915
         tools=[http_request, fetch_url, commit_and_open_pr],
         backend=sandbox_backend,
         middleware=[
+            TimeoutExecuteToolMiddleware(),
             ToolErrorMiddleware(),
             check_message_queue_before_model,
             post_to_linear_after_model,