diff --git a/crates/chat-cli/src/cli/chat/message.rs b/crates/chat-cli/src/cli/chat/message.rs
index 569846c1c2..f2c4ec7705 100644
--- a/crates/chat-cli/src/cli/chat/message.rs
+++ b/crates/chat-cli/src/cli/chat/message.rs
@@ -15,6 +15,11 @@ use tracing::{
     warn,
 };
 
+use crate::util::system_info::{
+    in_wsl,
+    os_version,
+};
+
 use super::consts::{
     MAX_CURRENT_WORKING_DIRECTORY_LEN,
     MAX_USER_MESSAGE_SIZE,
@@ -540,8 +545,21 @@ impl From<ToolUse> for AssistantToolUse {
 }
 
 pub fn build_env_state() -> EnvState {
+    // Build a detailed OS description using system_info
+    let os_description = match os_version() {
+        Some(version) => {
+            let base = version.to_string();
+            if in_wsl() {
+                format!("{} (WSL - Windows Subsystem for Linux)", base)
+            } else {
+                base
+            }
+        },
+        None => env::consts::OS.into(),
+    };
+
     let mut env_state = EnvState {
-        operating_system: Some(env::consts::OS.into()),
+        operating_system: Some(os_description),
         ..Default::default()
     };
 
diff --git a/crates/chat-cli/src/cli/chat/tools/tool_index.json b/crates/chat-cli/src/cli/chat/tools/tool_index.json
index 6ebeb50334..4d3a72c319 100644
--- a/crates/chat-cli/src/cli/chat/tools/tool_index.json
+++ b/crates/chat-cli/src/cli/chat/tools/tool_index.json
@@ -24,13 +24,13 @@
   },
   "execute_bash": {
     "name": "execute_bash",
-    "description": "Execute the specified bash command.",
+    "description": "Execute the specified shell command.\n\nIMPORTANT: Always check the 'operating_system' field in the user's environment context before generating commands.\n\nOS-specific guidance:\n- Windows: Use PowerShell syntax (Get-ChildItem instead of ls, Get-Content instead of cat, New-Item instead of touch, Remove-Item instead of rm, Copy-Item instead of cp, Move-Item instead of mv). Use backslashes for paths or forward slashes. Use $env:VAR for environment variables.\n- Linux/macOS: Use bash/POSIX syntax (ls, cat, touch, rm, cp, mv). Use forward slashes for paths. Use $VAR for environment variables.\n- WSL: The environment is Linux but may interact with Windows paths via /mnt/c/.\n\nNever assume Linux commands will work on Windows or vice versa. When the OS is unclear, ask the user to confirm.",
     "input_schema": {
       "type": "object",
       "properties": {
         "command": {
           "type": "string",
-          "description": "Bash command to execute"
+          "description": "Shell command to execute. Must use syntax appropriate for the user's operating system."
         },
         "summary": {
           "type": "string",