fix(browser): rewrite Camofox Docker loopback URLs (#25541)

Co-authored-by: Wysie <wysie@users.noreply.github.com>

cli.py

@@ -382,6 +382,10 @@ def load_cli_config() -> Dict[str, Any]:
             "inactivity_timeout": 120,  # Auto-cleanup inactive browser sessions after 2 min
             "record_sessions": False,  # Auto-record browser sessions as WebM videos
             "engine": "auto",  # Browser engine: auto (Chrome), lightpanda, chrome
+            "camofox": {
+                "rewrite_loopback_urls": False,
+                "loopback_host_alias": "host.docker.internal",
+            },
         },
         "compression": {
             "enabled": True,      # Auto-compress when approaching context limit

hermes_cli/config.py

@@ -850,6 +850,11 @@ DEFAULT_CONFIG = {
             "session_key": "",
             # Rehydrate tab_id from Camofox before creating a new tab.
             "adopt_existing_tab": False,
+            # Docker Camofox opens page URLs from inside the container. Enable
+            # this to rewrite loopback page URLs (localhost/127.0.0.1/::1) to a
+            # host alias while leaving CAMOFOX_URL itself unchanged.
+            "rewrite_loopback_urls": False,
+            "loopback_host_alias": "host.docker.internal",
         },
     },
 

tests/tools/test_browser_camofox.py

@@ -18,6 +18,7 @@ from tools.browser_camofox import (
     camofox_vision,
     check_camofox_available,
     is_camofox_mode,
+    _rewrite_loopback_url_for_camofox,
 )
 
 
@@ -57,6 +58,10 @@ class TestCamofoxMode:
 # ---------------------------------------------------------------------------
 
 
+def _config_with_camofox(**camofox_config):
+    return {"browser": {"camofox": camofox_config}}
+
+
 def _mock_response(status=200, json_data=None):
     resp = MagicMock()
     resp.status_code = status
@@ -71,6 +76,60 @@ def _mock_response(status=200, json_data=None):
 # ---------------------------------------------------------------------------
 
 
+class TestCamofoxLoopbackRewrite:
+    @patch("tools.browser_camofox.load_config")
+    def test_rewrites_localhost_when_enabled(self, mock_config, monkeypatch):
+        monkeypatch.delenv("CAMOFOX_REWRITE_LOOPBACK_URLS", raising=False)
+        monkeypatch.delenv("CAMOFOX_LOOPBACK_HOST_ALIAS", raising=False)
+        mock_config.return_value = _config_with_camofox(rewrite_loopback_urls=True)
+
+        rewritten, metadata = _rewrite_loopback_url_for_camofox("http://127.0.0.1:8766/#settings")
+
+        assert rewritten == "http://host.docker.internal:8766/#settings"
+        assert metadata == {
+            "from": "127.0.0.1",
+            "to": "host.docker.internal",
+            "original_url": "http://127.0.0.1:8766/#settings",
+            "rewritten_url": "http://host.docker.internal:8766/#settings",
+        }
+
+    @patch("tools.browser_camofox.load_config")
+    def test_rewrite_is_opt_in(self, mock_config, monkeypatch):
+        monkeypatch.delenv("CAMOFOX_REWRITE_LOOPBACK_URLS", raising=False)
+        mock_config.return_value = _config_with_camofox(rewrite_loopback_urls=False)
+
+        rewritten, metadata = _rewrite_loopback_url_for_camofox("http://localhost:3000/app?x=1")
+
+        assert rewritten == "http://localhost:3000/app?x=1"
+        assert metadata is None
+
+    @patch("tools.browser_camofox.load_config")
+    def test_preserves_public_urls_when_enabled(self, mock_config, monkeypatch):
+        monkeypatch.delenv("CAMOFOX_REWRITE_LOOPBACK_URLS", raising=False)
+        mock_config.return_value = _config_with_camofox(rewrite_loopback_urls=True)
+
+        rewritten, metadata = _rewrite_loopback_url_for_camofox("https://example.com:8443/path?q=1#top")
+
+        assert rewritten == "https://example.com:8443/path?q=1#top"
+        assert metadata is None
+
+    @patch("tools.browser_camofox.load_config")
+    def test_env_alias_takes_precedence(self, mock_config, monkeypatch):
+        monkeypatch.setenv("CAMOFOX_REWRITE_LOOPBACK_URLS", "true")
+        monkeypatch.setenv("CAMOFOX_LOOPBACK_HOST_ALIAS", "192.168.1.10")
+        mock_config.return_value = _config_with_camofox(
+            rewrite_loopback_urls=False,
+            loopback_host_alias="host.docker.internal",
+        )
+
+        rewritten, metadata = _rewrite_loopback_url_for_camofox("http://[::1]:8080/path")
+
+        assert rewritten == "http://192.168.1.10:8080/path"
+        assert metadata is not None
+        assert metadata["from"] == "::1"
+        assert metadata["to"] == "192.168.1.10"
+
+
 class TestCamofoxNavigate:
     @patch("tools.browser_camofox.requests.post")
     def test_creates_tab_on_first_navigate(self, mock_post, monkeypatch):
@@ -81,6 +140,24 @@ class TestCamofoxNavigate:
         assert result["success"] is True
         assert result["url"] == "https://example.com"
 
+    @patch("tools.browser_camofox.load_config")
+    @patch("tools.browser_camofox.requests.post")
+    def test_navigate_uses_rewritten_loopback_url(self, mock_post, mock_config, monkeypatch):
+        monkeypatch.setenv("CAMOFOX_URL", "http://localhost:9377")
+        monkeypatch.delenv("CAMOFOX_REWRITE_LOOPBACK_URLS", raising=False)
+        monkeypatch.delenv("CAMOFOX_LOOPBACK_HOST_ALIAS", raising=False)
+        mock_config.return_value = _config_with_camofox(rewrite_loopback_urls=True)
+        mock_post.return_value = _mock_response(json_data={"tabId": "tab_rewrite"})
+
+        result = json.loads(camofox_navigate("http://127.0.0.1:8766/#settings", task_id="t_rewrite"))
+
+        assert result["success"] is True
+        assert result["url"] == "http://host.docker.internal:8766/#settings"
+        assert result["requested_url"] == "http://127.0.0.1:8766/#settings"
+        assert result["url_rewrite"]["to"] == "host.docker.internal"
+        assert "Rewrote loopback URL" in result["warning"]
+        assert mock_post.call_args.kwargs["json"]["url"] == "http://host.docker.internal:8766/#settings"
+
     @patch("tools.browser_camofox.requests.post")
     def test_navigates_existing_tab(self, mock_post, monkeypatch):
         monkeypatch.setenv("CAMOFOX_URL", "http://localhost:9377")

tools/browser_camofox.py

@@ -18,6 +18,9 @@ Setup::
     docker run -p 9377:9377 -e CAMOFOX_PORT=9377 jo-inc/camofox-browser
 
 Then set ``CAMOFOX_URL=http://localhost:9377`` in ``~/.hermes/.env``.
+For Docker Camofox, optionally set ``CAMOFOX_REWRITE_LOOPBACK_URLS=true``
+so page URLs like ``http://127.0.0.1:3000`` are opened inside the
+container as ``http://host.docker.internal:3000``.
 """
 
 from __future__ import annotations
@@ -29,6 +32,7 @@ import os
 import threading
 import uuid
 from typing import Any, Dict, Optional
+from urllib.parse import SplitResult, urlsplit, urlunsplit
 
 import requests
 
@@ -159,6 +163,89 @@ def _adopt_existing_tab_enabled(camofox_cfg: Dict[str, Any]) -> bool:
     return bool(camofox_cfg.get("adopt_existing_tab"))
 
 
+def _loopback_rewrite_enabled(camofox_cfg: Dict[str, Any]) -> bool:
+    """Return whether loopback navigation URLs should be rewritten for Docker.
+
+    ``CAMOFOX_URL`` itself often points at a host-published Docker port such as
+    ``http://127.0.0.1:9377``.  That is correct for Hermes talking to the
+    Camofox control API, but a page URL like ``http://127.0.0.1:3000`` is opened
+    by the browser *inside* the Docker container.  In that context loopback
+    points at the container, not the host running the web app.
+
+    The rewrite is opt-in because non-Docker Camofox installs run the browser on
+    the host, where loopback URLs are already correct.
+    """
+    env_value = _env_flag("CAMOFOX_REWRITE_LOOPBACK_URLS")
+    if env_value is not None:
+        return env_value
+    return bool(camofox_cfg.get("rewrite_loopback_urls"))
+
+
+def _loopback_rewrite_host(camofox_cfg: Dict[str, Any]) -> str:
+    """Return the host alias used when rewriting loopback page URLs."""
+    return (
+        os.getenv("CAMOFOX_LOOPBACK_HOST_ALIAS", "").strip()
+        or str(camofox_cfg.get("loopback_host_alias") or "").strip()
+        or "host.docker.internal"
+    )
+
+
+def _is_loopback_hostname(hostname: Optional[str]) -> bool:
+    """Return True for localhost/127.0.0.0/8/::1-style hostnames."""
+    if not hostname:
+        return False
+    host = hostname.strip().strip("[]").lower()
+    if host in {"localhost", "localhost.localdomain"}:
+        return True
+    try:
+        import ipaddress
+
+        return ipaddress.ip_address(host).is_loopback
+    except ValueError:
+        return False
+
+
+def _rewrite_loopback_url_for_camofox(url: str) -> tuple[str, Optional[Dict[str, str]]]:
+    """Rewrite loopback page URLs for Docker-hosted Camofox, if configured.
+
+    Returns ``(rewritten_url, metadata)``.  ``metadata`` is present only when a
+    rewrite happened so the tool result can disclose the change to the model.
+    """
+    camofox_cfg = _get_camofox_config()
+    if not _loopback_rewrite_enabled(camofox_cfg):
+        return url, None
+
+    try:
+        parsed = urlsplit(url)
+    except ValueError:
+        return url, None
+
+    if parsed.scheme not in {"http", "https"} or not _is_loopback_hostname(parsed.hostname):
+        return url, None
+
+    alias = _loopback_rewrite_host(camofox_cfg)
+    if not alias:
+        return url, None
+
+    userinfo = ""
+    if parsed.username:
+        userinfo = parsed.username
+        if parsed.password:
+            userinfo += f":{parsed.password}"
+        userinfo += "@"
+    host_part = f"[{alias}]" if ":" in alias and not alias.startswith("[") else alias
+    port_part = f":{parsed.port}" if parsed.port else ""
+    rewritten = urlunsplit(
+        SplitResult(parsed.scheme, f"{userinfo}{host_part}{port_part}", parsed.path, parsed.query, parsed.fragment)
+    )
+    return rewritten, {
+        "from": parsed.hostname or "",
+        "to": alias,
+        "original_url": url,
+        "rewritten_url": rewritten,
+    }
+
+
 # ---------------------------------------------------------------------------
 # Session management
 # ---------------------------------------------------------------------------
@@ -336,23 +423,31 @@ def _delete(path: str, body: dict = None, timeout: int = _DEFAULT_TIMEOUT) -> di
 def camofox_navigate(url: str, task_id: Optional[str] = None) -> str:
     """Navigate to a URL via Camofox."""
     try:
+        browser_url, rewrite_info = _rewrite_loopback_url_for_camofox(url)
         session = _get_session(task_id)
         if not session["tab_id"]:
             # Create tab with the target URL directly
-            session = _ensure_tab(task_id, url)
-            data = {"ok": True, "url": url}
+            session = _ensure_tab(task_id, browser_url)
+            data = {"ok": True, "url": browser_url}
         else:
             # Navigate existing tab
             data = _post(
                 f"/tabs/{session['tab_id']}/navigate",
-                {"userId": session["user_id"], "url": url},
+                {"userId": session["user_id"], "url": browser_url},
                 timeout=60,
             )
         result = {
             "success": True,
-            "url": data.get("url", url),
+            "url": data.get("url", browser_url),
             "title": data.get("title", ""),
         }
+        if rewrite_info:
+            result["requested_url"] = url
+            result["url_rewrite"] = rewrite_info
+            result["warning"] = (
+                "Rewrote loopback URL for Docker-hosted Camofox: "
+                f"{rewrite_info['from']} -> {rewrite_info['to']}"
+            )
         vnc = get_vnc_url()
         if vnc:
             result["vnc_url"] = vnc

website/docs/user-guide/features/browser.md

@@ -185,6 +185,25 @@ Then set in `~/.hermes/.env`:
 CAMOFOX_URL=http://localhost:9377
 ```
 
+If Camofox is running in Docker and you want it to open web apps served from the host machine, enable loopback rewriting. `CAMOFOX_URL` should still point at the host-published control API, but page URLs such as `http://127.0.0.1:3000` must be opened from inside the container as `http://host.docker.internal:3000`:
+
+```yaml
+# ~/.hermes/config.yaml
+browser:
+  camofox:
+    rewrite_loopback_urls: true
+    loopback_host_alias: host.docker.internal  # default; use a LAN IP if needed
+```
+
+Equivalent env vars:
+
+```bash
+CAMOFOX_REWRITE_LOOPBACK_URLS=true
+CAMOFOX_LOOPBACK_HOST_ALIAS=host.docker.internal
+```
+
+The rewrite only applies to page navigation URLs with loopback hosts (`localhost`, `127.0.0.1`, `::1`). It does not change `CAMOFOX_URL`. Leave it disabled for non-Docker Camofox installs, where the browser already runs on the host and loopback URLs are correct.
+
 Or configure via `hermes tools` → Browser Automation → Camofox.
 
 When `CAMOFOX_URL` is set, all browser tools automatically route through Camofox instead of Browserbase or agent-browser.