fix: add macOS Homebrew paths to browser and terminal PATH resolution

On macOS with Homebrew (Apple Silicon), Node.js and agent-browser
binaries live under /opt/homebrew/bin/ which is not included in the
_SANE_PATH fallback used by browser_tool.py and environments/local.py.
When Hermes runs with a filtered PATH (e.g. as a systemd service),
these binaries are invisible, causing 'env: node: No such file or
directory' errors when using browser tools.

Changes:
- Add /opt/homebrew/bin and /opt/homebrew/sbin to _SANE_PATH in both
  browser_tool.py and environments/local.py
- Add _discover_homebrew_node_dirs() to find versioned Node installs
  (e.g. brew install node@24) that aren't linked into /opt/homebrew/bin
- Extend _find_agent_browser() to search Homebrew and Hermes-managed
  dirs when agent-browser isn't on the current PATH
- Include discovered Homebrew node dirs in subprocess PATH when
  launching agent-browser
- Add 11 new tests covering all Homebrew path discovery logic

tests/tools/test_browser_homebrew_paths.py

@@ -0,0 +1,259 @@
+"""Tests for macOS Homebrew PATH discovery in browser_tool.py."""
+
+import json
+import os
+import subprocess
+from pathlib import Path
+from unittest.mock import patch, MagicMock, mock_open
+
+import pytest
+
+from tools.browser_tool import (
+    _discover_homebrew_node_dirs,
+    _find_agent_browser,
+    _run_browser_command,
+    _SANE_PATH,
+)
+
+
+class TestSanePath:
+    """Verify _SANE_PATH includes Homebrew directories."""
+
+    def test_includes_homebrew_bin(self):
+        assert "/opt/homebrew/bin" in _SANE_PATH
+
+    def test_includes_homebrew_sbin(self):
+        assert "/opt/homebrew/sbin" in _SANE_PATH
+
+    def test_includes_standard_dirs(self):
+        assert "/usr/local/bin" in _SANE_PATH
+        assert "/usr/bin" in _SANE_PATH
+        assert "/bin" in _SANE_PATH
+
+
+class TestDiscoverHomebrewNodeDirs:
+    """Tests for _discover_homebrew_node_dirs()."""
+
+    def test_returns_empty_when_no_homebrew(self):
+        """Non-macOS systems without /opt/homebrew/opt should return empty."""
+        with patch("os.path.isdir", return_value=False):
+            assert _discover_homebrew_node_dirs() == []
+
+    def test_finds_versioned_node_dirs(self):
+        """Should discover node@20/bin, node@24/bin etc."""
+        entries = ["node@20", "node@24", "openssl", "node", "python@3.12"]
+
+        def mock_isdir(p):
+            if p == "/opt/homebrew/opt":
+                return True
+            # node@20/bin and node@24/bin exist
+            if p in (
+                "/opt/homebrew/opt/node@20/bin",
+                "/opt/homebrew/opt/node@24/bin",
+            ):
+                return True
+            return False
+
+        with patch("os.path.isdir", side_effect=mock_isdir), \
+             patch("os.listdir", return_value=entries):
+            result = _discover_homebrew_node_dirs()
+
+        assert len(result) == 2
+        assert "/opt/homebrew/opt/node@20/bin" in result
+        assert "/opt/homebrew/opt/node@24/bin" in result
+
+    def test_excludes_plain_node(self):
+        """'node' (unversioned) should be excluded — covered by /opt/homebrew/bin."""
+        with patch("os.path.isdir", return_value=True), \
+             patch("os.listdir", return_value=["node"]):
+            result = _discover_homebrew_node_dirs()
+        assert result == []
+
+    def test_handles_oserror_gracefully(self):
+        """Should return empty list if listdir raises OSError."""
+        with patch("os.path.isdir", return_value=True), \
+             patch("os.listdir", side_effect=OSError("Permission denied")):
+            assert _discover_homebrew_node_dirs() == []
+
+
+class TestFindAgentBrowser:
+    """Tests for _find_agent_browser() Homebrew path search."""
+
+    def test_finds_in_current_path(self):
+        """Should return result from shutil.which if available on current PATH."""
+        with patch("shutil.which", return_value="/usr/local/bin/agent-browser"):
+            assert _find_agent_browser() == "/usr/local/bin/agent-browser"
+
+    def test_finds_in_homebrew_bin(self):
+        """Should search Homebrew dirs when not found on current PATH."""
+        def mock_which(cmd, path=None):
+            if path and "/opt/homebrew/bin" in path and cmd == "agent-browser":
+                return "/opt/homebrew/bin/agent-browser"
+            return None
+
+        with patch("shutil.which", side_effect=mock_which), \
+             patch("os.path.isdir", return_value=True), \
+             patch(
+                 "tools.browser_tool._discover_homebrew_node_dirs",
+                 return_value=[],
+             ):
+            result = _find_agent_browser()
+            assert result == "/opt/homebrew/bin/agent-browser"
+
+    def test_finds_npx_in_homebrew(self):
+        """Should find npx in Homebrew paths as a fallback."""
+        def mock_which(cmd, path=None):
+            if cmd == "agent-browser":
+                return None
+            if cmd == "npx":
+                if path and "/opt/homebrew/bin" in path:
+                    return "/opt/homebrew/bin/npx"
+                return None
+            return None
+
+        # Mock Path.exists() to prevent the local node_modules check from matching
+        original_path_exists = Path.exists
+
+        def mock_path_exists(self):
+            if "node_modules" in str(self) and "agent-browser" in str(self):
+                return False
+            return original_path_exists(self)
+
+        with patch("shutil.which", side_effect=mock_which), \
+             patch("os.path.isdir", return_value=True), \
+             patch.object(Path, "exists", mock_path_exists), \
+             patch(
+                 "tools.browser_tool._discover_homebrew_node_dirs",
+                 return_value=[],
+             ):
+            result = _find_agent_browser()
+            assert result == "npx agent-browser"
+
+    def test_raises_when_not_found(self):
+        """Should raise FileNotFoundError when nothing works."""
+        original_path_exists = Path.exists
+
+        def mock_path_exists(self):
+            if "node_modules" in str(self) and "agent-browser" in str(self):
+                return False
+            return original_path_exists(self)
+
+        with patch("shutil.which", return_value=None), \
+             patch("os.path.isdir", return_value=False), \
+             patch.object(Path, "exists", mock_path_exists), \
+             patch(
+                 "tools.browser_tool._discover_homebrew_node_dirs",
+                 return_value=[],
+             ):
+            with pytest.raises(FileNotFoundError, match="agent-browser CLI not found"):
+                _find_agent_browser()
+
+
+class TestRunBrowserCommandPathConstruction:
+    """Verify _run_browser_command() includes Homebrew node dirs in subprocess PATH."""
+
+    def test_subprocess_path_includes_homebrew_node_dirs(self, tmp_path):
+        """When _discover_homebrew_node_dirs returns dirs, they should appear
+        in the subprocess env PATH passed to Popen."""
+        captured_env = {}
+
+        # Create a mock Popen that captures the env dict
+        mock_proc = MagicMock()
+        mock_proc.returncode = 0
+        mock_proc.wait.return_value = 0
+
+        def capture_popen(cmd, **kwargs):
+            captured_env.update(kwargs.get("env", {}))
+            return mock_proc
+
+        fake_session = {
+            "session_name": "test-session",
+            "session_id": "test-id",
+            "cdp_url": None,
+        }
+
+        # Write fake JSON output to the stdout temp file
+        fake_json = json.dumps({"success": True})
+        stdout_file = tmp_path / "stdout"
+        stdout_file.write_text(fake_json)
+
+        fake_homebrew_dirs = [
+            "/opt/homebrew/opt/node@24/bin",
+            "/opt/homebrew/opt/node@20/bin",
+        ]
+
+        # We need os.path.isdir to return True for our fake dirs
+        # but we also need real isdir for tmp_path operations
+        real_isdir = os.path.isdir
+
+        def selective_isdir(p):
+            if p in fake_homebrew_dirs or p.startswith(str(tmp_path)):
+                return True
+            if "/opt/homebrew/" in p:
+                return True  # _SANE_PATH dirs
+            return real_isdir(p)
+
+        with patch("tools.browser_tool._find_agent_browser", return_value="/usr/local/bin/agent-browser"), \
+             patch("tools.browser_tool._get_session_info", return_value=fake_session), \
+             patch("tools.browser_tool._socket_safe_tmpdir", return_value=str(tmp_path)), \
+             patch("tools.browser_tool._discover_homebrew_node_dirs", return_value=fake_homebrew_dirs), \
+             patch("os.path.isdir", side_effect=selective_isdir), \
+             patch("subprocess.Popen", side_effect=capture_popen), \
+             patch("os.open", return_value=99), \
+             patch("os.close"), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch.dict(os.environ, {"PATH": "/usr/bin:/bin", "HOME": "/home/test"}, clear=True):
+            # The function reads from temp files for stdout/stderr
+            with patch("builtins.open", mock_open(read_data=fake_json)):
+                _run_browser_command("test-task", "navigate", ["https://example.com"])
+
+        # Verify Homebrew node dirs made it into the subprocess PATH
+        result_path = captured_env.get("PATH", "")
+        assert "/opt/homebrew/opt/node@24/bin" in result_path
+        assert "/opt/homebrew/opt/node@20/bin" in result_path
+        assert "/opt/homebrew/bin" in result_path  # from _SANE_PATH
+
+    def test_subprocess_path_includes_sane_path_homebrew(self, tmp_path):
+        """_SANE_PATH Homebrew entries should appear even without versioned node dirs."""
+        captured_env = {}
+
+        mock_proc = MagicMock()
+        mock_proc.returncode = 0
+        mock_proc.wait.return_value = 0
+
+        def capture_popen(cmd, **kwargs):
+            captured_env.update(kwargs.get("env", {}))
+            return mock_proc
+
+        fake_session = {
+            "session_name": "test-session",
+            "session_id": "test-id",
+            "cdp_url": None,
+        }
+
+        fake_json = json.dumps({"success": True})
+        real_isdir = os.path.isdir
+
+        def selective_isdir(p):
+            if "/opt/homebrew/" in p:
+                return True
+            if p.startswith(str(tmp_path)):
+                return True
+            return real_isdir(p)
+
+        with patch("tools.browser_tool._find_agent_browser", return_value="/usr/local/bin/agent-browser"), \
+             patch("tools.browser_tool._get_session_info", return_value=fake_session), \
+             patch("tools.browser_tool._socket_safe_tmpdir", return_value=str(tmp_path)), \
+             patch("tools.browser_tool._discover_homebrew_node_dirs", return_value=[]), \
+             patch("os.path.isdir", side_effect=selective_isdir), \
+             patch("subprocess.Popen", side_effect=capture_popen), \
+             patch("os.open", return_value=99), \
+             patch("os.close"), \
+             patch("tools.interrupt.is_interrupted", return_value=False), \
+             patch.dict(os.environ, {"PATH": "/usr/bin:/bin", "HOME": "/home/test"}, clear=True):
+            with patch("builtins.open", mock_open(read_data=fake_json)):
+                _run_browser_command("test-task", "navigate", ["https://example.com"])
+
+        result_path = captured_env.get("PATH", "")
+        assert "/opt/homebrew/bin" in result_path
+        assert "/opt/homebrew/sbin" in result_path

tests/tools/test_local_env_blocklist.py

@@ -288,3 +288,34 @@ class TestBlocklistCoverage:
             "DAYTONA_API_KEY",
         }
         assert extras.issubset(_HERMES_PROVIDER_ENV_BLOCKLIST)
+
+
+class TestSanePathIncludesHomebrew:
+    """Verify _SANE_PATH includes macOS Homebrew directories."""
+
+    def test_sane_path_includes_homebrew_bin(self):
+        from tools.environments.local import _SANE_PATH
+        assert "/opt/homebrew/bin" in _SANE_PATH
+
+    def test_sane_path_includes_homebrew_sbin(self):
+        from tools.environments.local import _SANE_PATH
+        assert "/opt/homebrew/sbin" in _SANE_PATH
+
+    def test_make_run_env_appends_homebrew_on_minimal_path(self):
+        """When PATH is minimal (no /usr/bin), _make_run_env should append
+        _SANE_PATH which now includes Homebrew dirs."""
+        from tools.environments.local import _make_run_env
+        minimal_env = {"PATH": "/some/custom/bin"}
+        with patch.dict(os.environ, minimal_env, clear=True):
+            result = _make_run_env({})
+        assert "/opt/homebrew/bin" in result["PATH"]
+        assert "/opt/homebrew/sbin" in result["PATH"]
+
+    def test_make_run_env_does_not_duplicate_on_full_path(self):
+        """When PATH already has /usr/bin, _make_run_env should not append."""
+        from tools.environments.local import _make_run_env
+        full_env = {"PATH": "/usr/bin:/bin"}
+        with patch.dict(os.environ, full_env, clear=True):
+            result = _make_run_env({})
+        # Should keep existing PATH unchanged
+        assert result["PATH"] == "/usr/bin:/bin"

tools/browser_tool.py

@@ -76,8 +76,35 @@ from tools.browser_providers.browser_use import BrowserUseProvider
 
 logger = logging.getLogger(__name__)
 
-# Standard PATH entries for environments with minimal PATH (e.g. systemd services)
-_SANE_PATH = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+# Standard PATH entries for environments with minimal PATH (e.g. systemd services).
+# Includes macOS Homebrew paths (/opt/homebrew/* for Apple Silicon).
+_SANE_PATH = (
+    "/opt/homebrew/bin:/opt/homebrew/sbin:"
+    "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+)
+
+
+def _discover_homebrew_node_dirs() -> list[str]:
+    """Find Homebrew versioned Node.js bin directories (e.g. node@20, node@24).
+
+    When Node is installed via ``brew install node@24`` and NOT linked into
+    /opt/homebrew/bin, the binary lives only in /opt/homebrew/opt/node@24/bin/.
+    This function discovers those paths so they can be added to subprocess PATH.
+    """
+    dirs: list[str] = []
+    homebrew_opt = "/opt/homebrew/opt"
+    if not os.path.isdir(homebrew_opt):
+        return dirs
+    try:
+        for entry in os.listdir(homebrew_opt):
+            if entry.startswith("node") and entry != "node":
+                # e.g. node@20, node@24
+                bin_dir = os.path.join(homebrew_opt, entry, "bin")
+                if os.path.isdir(bin_dir):
+                    dirs.append(bin_dir)
+    except OSError:
+        pass
+    return dirs
 
 # Throttle screenshot cleanup to avoid repeated full directory scans.
 _last_screenshot_cleanup_by_dir: dict[str, float] = {}
@@ -619,7 +646,8 @@ def _find_agent_browser() -> str:
     """
     Find the agent-browser CLI executable.
     
-    Checks in order: PATH, local node_modules/.bin/, npx fallback.
+    Checks in order: current PATH, Homebrew/common bin dirs, Hermes-managed
+    node, local node_modules/.bin/, npx fallback.
     
     Returns:
         Path to agent-browser executable
@@ -632,15 +660,36 @@ def _find_agent_browser() -> str:
     which_result = shutil.which("agent-browser")
     if which_result:
         return which_result
-    
+
+    # Build an extended search PATH including Homebrew and Hermes-managed dirs.
+    # This covers macOS where the process PATH may not include Homebrew paths.
+    extra_dirs: list[str] = []
+    for d in ["/opt/homebrew/bin", "/usr/local/bin"]:
+        if os.path.isdir(d):
+            extra_dirs.append(d)
+    extra_dirs.extend(_discover_homebrew_node_dirs())
+
+    hermes_home = Path(os.environ.get("HERMES_HOME", Path.home() / ".hermes"))
+    hermes_node_bin = str(hermes_home / "node" / "bin")
+    if os.path.isdir(hermes_node_bin):
+        extra_dirs.append(hermes_node_bin)
+
+    if extra_dirs:
+        extended_path = os.pathsep.join(extra_dirs)
+        which_result = shutil.which("agent-browser", path=extended_path)
+        if which_result:
+            return which_result
+
     # Check local node_modules/.bin/ (npm install in repo root)
     repo_root = Path(__file__).parent.parent
     local_bin = repo_root / "node_modules" / ".bin" / "agent-browser"
     if local_bin.exists():
         return str(local_bin)
     
-    # Check common npx locations
+    # Check common npx locations (also search extended dirs)
     npx_path = shutil.which("npx")
+    if not npx_path and extra_dirs:
+        npx_path = shutil.which("npx", path=os.pathsep.join(extra_dirs))
     if npx_path:
         return "npx agent-browser"
     
@@ -742,13 +791,18 @@ def _run_browser_command(
         
         browser_env = {**os.environ}
 
-        # Ensure PATH includes Hermes-managed Node first, then standard system dirs.
+        # Ensure PATH includes Hermes-managed Node first, Homebrew versioned
+        # node dirs (for macOS ``brew install node@24``), then standard system dirs.
         hermes_home = Path(os.environ.get("HERMES_HOME", Path.home() / ".hermes"))
         hermes_node_bin = str(hermes_home / "node" / "bin")
 
         existing_path = browser_env.get("PATH", "")
         path_parts = [p for p in existing_path.split(":") if p]
-        candidate_dirs = [hermes_node_bin] + [p for p in _SANE_PATH.split(":") if p]
+        candidate_dirs = (
+            [hermes_node_bin]
+            + _discover_homebrew_node_dirs()
+            + [p for p in _SANE_PATH.split(":") if p]
+        )
 
         for part in reversed(candidate_dirs):
             if os.path.isdir(part) and part not in path_parts:

tools/environments/local.py

@@ -254,7 +254,12 @@ def _clean_shell_noise(output: str) -> str:
     return result
 
 
-_SANE_PATH = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+# Standard PATH entries for environments with minimal PATH (e.g. systemd services).
+# Includes macOS Homebrew paths (/opt/homebrew/* for Apple Silicon).
+_SANE_PATH = (
+    "/opt/homebrew/bin:/opt/homebrew/sbin:"
+    "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+)
 
 
 def _make_run_env(env: dict) -> dict: