hermes-agent/tools/open_preview_tool.py
Brooklyn Nicholson 70ba3c4828 feat(desktop): agent can focus panes + shared desktop-UI event bridge
Extract the open_preview emitter into a shared tools/desktop_ui bridge
(one gateway-injected sink, routed by HERMES_UI_SESSION_ID) and add a
second desktop-gated tool on top of it:

- focus_pane(chat|files|terminal|review|sessions) -> pane.reveal event.
  The desktop runs each pane's own reveal path (revealDesktopPane table)
  and only acts on the active window -- a background turn never moves the
  user's focus (desktop AGENTS.md: offer, don't hijack).

open_preview now emits through the same bridge. Both tools are check_fn
on HERMES_DESKTOP (zero footprint elsewhere), sitting beside
read_terminal/close_terminal in _HERMES_CORE_TOOLS.

Deliberately not adding run_slash: letting the agent fire slash commands
mid-turn (/model, /new, /clear) fights prompt-cache + conversation
invariants.
2026-07-22 12:13:01 -05:00

97 lines
3.5 KiB
Python

#!/usr/bin/env python3
"""Open a URL, dev server, or file in the Hermes desktop GUI's preview pane.
Gated on ``HERMES_DESKTOP`` (like ``read_terminal`` / ``close_terminal``) so it
never appears outside the GUI. Emits ``preview.open`` through the shared
``desktop_ui`` bridge; the renderer opens the pane beside the chat for the
window that asked and never steals focus for a background session.
"""
import json
import re
from tools import desktop_ui
from tools.registry import registry, tool_error
from utils import env_var_enabled
def _normalize_target(raw: str) -> str:
"""Coax a bare host/domain into a fetchable URL; leave paths + schemes alone.
``www.cnn.com`` → ``https://www.cnn.com``; ``localhost:3000`` →
``http://localhost:3000``. File paths and explicit schemes pass through for
the renderer's preview normalizer to classify.
"""
v = raw.strip().strip("`").strip()
if not v or "://" in v or v.startswith(("/", "./", "../", "~", "file:")):
return v
if re.match(r"^(localhost|127\.0\.0\.1|0\.0\.0\.0|\[::1\])(:\d+)?(/|$)", v, re.I):
return "http://" + v
if re.match(r"^[\w.-]+\.[a-z]{2,}(:\d+)?(/.*)?$", v, re.I):
return "https://" + v
return v
def open_preview_tool(url: str, label: str = "") -> str:
"""Ask the desktop GUI to show ``url`` in the preview pane beside the chat."""
target = _normalize_target(url or "")
if not target:
return tool_error(
"url is required — a web URL (https://…), a localhost dev server, or a "
"file path to show in the preview pane."
)
label = (label or "").strip()
try:
ok = desktop_ui.emit("preview.open", {"url": target, "label": label})
except Exception as exc:
return tool_error(f"Failed to open the preview pane: {exc}")
if not ok:
return tool_error("The preview pane is only available in the Hermes desktop app.")
return json.dumps({"success": True, "url": target, "label": label}, ensure_ascii=False)
def check_open_preview_requirements() -> bool:
"""Desktop GUI only — HERMES_DESKTOP is set on the gateway the app spawns."""
return env_var_enabled("HERMES_DESKTOP")
OPEN_PREVIEW_SCHEMA = {
"name": "open_preview",
"description": (
"Open something in the preview pane beside the chat in the Hermes desktop "
"app. Use this when the user asks to see a page, dev server, or file in the "
"preview pane — e.g. \"open cnn.com in the preview pane\" or \"preview "
"localhost:3000\". Accepts a web URL (a bare domain like www.cnn.com is fine), "
"a localhost dev-server URL, or a file path (HTML renders live; other files "
"show their contents). The pane opens for the current window only."
),
"parameters": {
"type": "object",
"properties": {
"url": {
"type": "string",
"description": (
"What to preview: a web URL (https://… or a bare domain), a "
"localhost URL (localhost:3000), or a file path."
),
},
"label": {
"type": "string",
"description": "Optional tab label; defaults to the target's name.",
},
},
"required": ["url"],
},
}
registry.register(
name="open_preview",
toolset="terminal",
schema=OPEN_PREVIEW_SCHEMA,
handler=lambda args, **kw: open_preview_tool(url=args.get("url", ""), label=args.get("label", "")),
check_fn=check_open_preview_requirements,
emoji="🖼️",
)