fix: improve browser command environment setup

Enhanced the environment setup for browser commands by ensuring the PATH variable includes standard directories, addressing potential issues with minimal PATH in systemd services. Additionally, updated the logging of stderr to use a warning level on failure for better visibility of errors. This change improves the robustness of subprocess execution in the browser tool.

tools/browser_tool.py

@@ -795,10 +795,12 @@ def _run_browser_command(
         )
         os.makedirs(task_socket_dir, exist_ok=True)
         
-        browser_env = {
-            **os.environ,
-            "AGENT_BROWSER_SOCKET_DIR": task_socket_dir,
-        }
+        browser_env = {**os.environ}
+        # Ensure PATH includes standard dirs (systemd services may have minimal PATH)
+        _SANE_PATH = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+        if "/usr/bin" not in browser_env.get("PATH", "").split(":"):
+            browser_env["PATH"] = f"{browser_env.get('PATH', '')}:{_SANE_PATH}"
+        browser_env["AGENT_BROWSER_SOCKET_DIR"] = task_socket_dir
         
         result = subprocess.run(
             cmd_parts,
@@ -808,9 +810,10 @@ def _run_browser_command(
             env=browser_env,
         )
         
-        # Log stderr for diagnostics (agent-browser may emit warnings there)
+        # Log stderr for diagnostics — use warning level on failure so it's visible
         if result.stderr and result.stderr.strip():
-            logger.debug("stderr from '%s': %s", command, result.stderr.strip()[:200])
+            level = logging.WARNING if result.returncode != 0 else logging.DEBUG
+            logger.log(level, "browser '%s' stderr: %s", command, result.stderr.strip()[:500])
         
         # Parse JSON output
         if result.stdout.strip():