diff --git a/README.md b/README.md
index d2483e4..ad81dd6 100644
--- a/README.md
+++ b/README.md
@@ -16,10 +16,13 @@
 
 ⚡️ Delivers core agent functionality in just **~4,000** lines of code — **99% smaller** than Clawdbot's 430k+ lines.
 
-📏 Real-time line count: **3,955 lines** (run `bash core_agent_lines.sh` to verify anytime)
+📏 Real-time line count: **3,966 lines** (run `bash core_agent_lines.sh` to verify anytime)
 
 ## 📢 News
 
+- **2026-02-24** 🚀 Released **v0.1.4.post2** — a reliability-focused release with a redesigned heartbeat, prompt cache optimization, and hardened provider & channel stability. See [release notes](https://github.com/HKUDS/nanobot/releases/tag/v0.1.4.post2) for details.
+- **2026-02-23** 🔧 Virtual tool-call heartbeat, prompt cache optimization, Slack mrkdwn fixes.
+- **2026-02-22** 🛡️ Slack thread isolation, Discord typing fix, agent reliability improvements.
 - **2026-02-21** 🎉 Released **v0.1.4.post1** — new providers, media support across channels, and major stability improvements. See [release notes](https://github.com/HKUDS/nanobot/releases/tag/v0.1.4.post1) for details.
 - **2026-02-20** 🐦 Feishu now receives multimodal files from users. More reliable memory under the hood.
 - **2026-02-19** ✨ Slack now sends files, Discord splits long messages, and subagents work in CLI mode.
@@ -804,6 +807,7 @@ MCP tools are automatically discovered and registered on startup. The LLM can us
 | Option | Default | Description |
 |--------|---------|-------------|
 | `tools.restrictToWorkspace` | `false` | When `true`, restricts **all** agent tools (shell, file read/write/edit, list) to the workspace directory. Prevents path traversal and out-of-scope access. |
+| `tools.exec.pathAppend` | `""` | Extra directories to append to `PATH` when running shell commands (e.g. `/usr/sbin` for `ufw`). |
 | `channels.*.allowFrom` | `[]` (allow all) | Whitelist of user IDs. Empty = allow everyone; non-empty = only listed users can interact. |
 
 
diff --git a/nanobot/agent/loop.py b/nanobot/agent/loop.py
index 8be8e51..c5e2a00 100644
--- a/nanobot/agent/loop.py
+++ b/nanobot/agent/loop.py
@@ -110,6 +110,7 @@ class AgentLoop:
             working_dir=str(self.workspace),
             timeout=self.exec_config.timeout,
             restrict_to_workspace=self.restrict_to_workspace,
+            path_append=self.exec_config.path_append,
         ))
         self.tools.register(WebSearchTool(api_key=self.brave_api_key))
         self.tools.register(WebFetchTool())
diff --git a/nanobot/agent/subagent.py b/nanobot/agent/subagent.py
index d87c61a..7269dee 100644
--- a/nanobot/agent/subagent.py
+++ b/nanobot/agent/subagent.py
@@ -111,6 +111,7 @@ class SubagentManager:
                 working_dir=str(self.workspace),
                 timeout=self.exec_config.timeout,
                 restrict_to_workspace=self.restrict_to_workspace,
+                path_append=self.exec_config.path_append,
             ))
             tools.register(WebSearchTool(api_key=self.brave_api_key))
             tools.register(WebFetchTool())
diff --git a/nanobot/agent/tools/shell.py b/nanobot/agent/tools/shell.py
index e3592a7..c3810b2 100644
--- a/nanobot/agent/tools/shell.py
+++ b/nanobot/agent/tools/shell.py
@@ -19,6 +19,7 @@ class ExecTool(Tool):
         deny_patterns: list[str] | None = None,
         allow_patterns: list[str] | None = None,
         restrict_to_workspace: bool = False,
+        path_append: str = "",
     ):
         self.timeout = timeout
         self.working_dir = working_dir
@@ -35,6 +36,7 @@ class ExecTool(Tool):
         ]
         self.allow_patterns = allow_patterns or []
         self.restrict_to_workspace = restrict_to_workspace
+        self.path_append = path_append
     
     @property
     def name(self) -> str:
@@ -67,12 +69,17 @@ class ExecTool(Tool):
         if guard_error:
             return guard_error
         
+        env = os.environ.copy()
+        if self.path_append:
+            env["PATH"] = env.get("PATH", "") + os.pathsep + self.path_append
+
         try:
             process = await asyncio.create_subprocess_shell(
                 command,
                 stdout=asyncio.subprocess.PIPE,
                 stderr=asyncio.subprocess.PIPE,
                 cwd=cwd,
+                env=env,
             )
             
             try:
diff --git a/nanobot/config/schema.py b/nanobot/config/schema.py
index 215f38d..32b85cf 100644
--- a/nanobot/config/schema.py
+++ b/nanobot/config/schema.py
@@ -260,6 +260,7 @@ class ExecToolConfig(Base):
     """Shell exec tool configuration."""
 
     timeout: int = 60
+    path_append: str = ""
 
 
 class MCPServerConfig(Base):
diff --git a/nanobot/providers/litellm_provider.py b/nanobot/providers/litellm_provider.py
index 7402a2b..0918954 100644
--- a/nanobot/providers/litellm_provider.py
+++ b/nanobot/providers/litellm_provider.py
@@ -12,8 +12,9 @@ from nanobot.providers.base import LLMProvider, LLMResponse, ToolCallRequest
 from nanobot.providers.registry import find_by_model, find_gateway
 
 
-# Standard OpenAI chat-completion message keys; extras (e.g. reasoning_content) are stripped for strict providers.
-_ALLOWED_MSG_KEYS = frozenset({"role", "content", "tool_calls", "tool_call_id", "name"})
+# Standard OpenAI chat-completion message keys plus reasoning_content for
+# thinking-enabled models (Kimi k2.5, DeepSeek-R1, etc.).
+_ALLOWED_MSG_KEYS = frozenset({"role", "content", "tool_calls", "tool_call_id", "name", "reasoning_content"})
 
 
 class LiteLLMProvider(LLMProvider):