hermes-agent/tools/computer_use/tool.py
Brooklyn Nicholson 4e49af94be fix(computer_use): stop the cua-driver child on exit
CuaDriverBackend caches a long-lived cua-driver subprocess for the life of
the Hermes process, and stop() was never called from anywhere — the driver
outlived the session that spawned it. #69903 stopped the orphan from pegging
a core by disabling the cursor overlay, but left the process behind; this is
item 3 of #28152 ("Hermes does not keep the driver alive after tool
completion").

Register an atexit hook, mirroring browser_tool's
atexit.register(_emergency_cleanup_all_sessions). atexit only, no signal
handlers, for the prompt_toolkit reason documented there. reset_backend_for_tests
now reuses the same teardown instead of repeating it.
2026-07-26 03:38:23 -05:00

1047 lines
42 KiB
Python

"""Entry point for the `computer_use` tool.
Universal (any-model) desktop control across macOS, Windows, and Linux via
cua-driver's background computer-use primitive. Replaces #4562's
Anthropic-native `computer_20251124` approach — the schema here is standard
OpenAI function-calling so every tool-capable model can drive it.
Linux is the most recent runtime (X11 + Wayland, via cua-driver-rs's
AT-SPI tree path); it is enabled here alongside macOS and Windows. When a
host's display server or accessibility stack isn't reachable, cua-driver's
`health_report` (surfaced by `hermes computer-use doctor`) reports the
exact blocked check rather than the toolset silently failing.
Return contract
---------------
For text-only results (wait, key, list_apps, focus_app, failures, etc.):
JSON string.
For captures / actions with `capture_after=True`:
A dict wrapped as the OpenAI-style multi-part tool-message content:
{
"_multimodal": True,
"content": [
{"type": "text", "text": "<human-readable summary + SOM index>"},
{"type": "image_url",
"image_url": {"url": "data:image/png;base64,<b64>"}},
],
"text_summary": "<text used for fallback string content>",
}
run_agent.py's tool-message builder inspects `_multimodal` and emits a
list-shaped `content` for OpenAI-compatible providers. The Anthropic
adapter splices the base64 image into a `tool_result` block (see
`agent/anthropic_adapter.py`). Every provider that supports multi-part
tool content gets the image; text-only providers see the summary only.
"""
from __future__ import annotations
import atexit
import base64
import json
import logging
import os
import re
import struct
import sys
import threading
from typing import Any, Dict, List, Optional, Tuple
from tools.computer_use.backend import (
ActionResult,
CaptureResult,
ComputerUseBackend,
UIElement,
)
logger = logging.getLogger(__name__)
# ---------------------------------------------------------------------------
# Approval & safety
# ---------------------------------------------------------------------------
_approval_callback = None
def set_approval_callback(cb) -> None:
"""Register a callback for computer_use approval prompts (used by CLI).
Matches the terminal_tool._approval_callback pattern. The callback
receives (action, args, summary) and returns one of:
"approve_once" | "approve_session" | "always_approve" | "deny".
"""
global _approval_callback
_approval_callback = cb
# Actions that read, not mutate. Always allowed.
_SAFE_ACTIONS = frozenset({"capture", "wait", "list_apps"})
# Actions that mutate user-visible state. Go through approval.
_DESTRUCTIVE_ACTIONS = frozenset({
"click", "double_click", "right_click", "middle_click",
"drag", "scroll", "type", "key", "set_value", "focus_app",
})
# Hard-blocked key combinations. Mirrored from #4562 — these are destructive
# regardless of approval level (e.g. logout kills the session Hermes runs in).
_BLOCKED_KEY_COMBOS = {
frozenset({"cmd", "shift", "backspace"}), # empty trash
frozenset({"cmd", "option", "backspace"}), # force delete
frozenset({"cmd", "ctrl", "q"}), # lock screen
frozenset({"cmd", "shift", "q"}), # log out
frozenset({"cmd", "option", "shift", "q"}), # force log out
# Windows secure/session shortcuts. The Windows driver accepts Win-key
# combos, and Alt is canonicalized to option below, so block the
# destructive variants before any backend sees them.
frozenset({"win", "l"}),
frozenset({"ctrl", "option", "delete"}),
frozenset({"ctrl", "option", "del"}),
frozenset({"option", "f4"}),
}
_KEY_ALIASES = {
"command": "cmd", "control": "ctrl", "alt": "option", "": "cmd", "": "option",
"windows": "win", "super": "win", "meta": "win",
}
def _canon_key_combo(keys: str) -> frozenset:
parts = [p.strip().lower() for p in re.split(r"\s*\+\s*", keys) if p.strip()]
parts = [_KEY_ALIASES.get(p, p) for p in parts]
return frozenset(parts)
# Dangerous text patterns for the `type` action. Same list as #4562.
_BLOCKED_TYPE_PATTERNS = [
re.compile(r"curl\s+[^|]*\|\s*bash", re.IGNORECASE),
re.compile(r"curl\s+[^|]*\|\s*sh", re.IGNORECASE),
re.compile(r"wget\s+[^|]*\|\s*bash", re.IGNORECASE),
re.compile(r"\bsudo\s+rm\s+-[rf]", re.IGNORECASE),
re.compile(r"\brm\s+-rf\s+/\s*$", re.IGNORECASE),
re.compile(r":\s*\(\)\s*\{\s*:\|:\s*&\s*\}", re.IGNORECASE), # fork bomb
]
def _is_blocked_type(text: str) -> Optional[str]:
for pat in _BLOCKED_TYPE_PATTERNS:
if pat.search(text):
return pat.pattern
return None
# ---------------------------------------------------------------------------
# Backend selection — env-swappable for tests
# ---------------------------------------------------------------------------
# Per-process cached backend; lazily instantiated on first call.
_backend_lock = threading.Lock()
# Process-scoped aux-vision routing cache: (provider, model) → bool.
_AUX_VISION_ROUTE_CACHE: Dict[Tuple[str, str], bool] = {}
_backend: Optional[ComputerUseBackend] = None
# Approval state, scoped per conversation/run (keyed by session_id) so a
# gateway serving concurrent sessions can't leak one run's "always approve"
# unlock into another. Falls back to a shared "" bucket for callers that
# don't pass a session_id (e.g. the classic single-run CLI). Values:
# _session_auto_approve[sid] -> bool ("always_approve everything")
# _always_allow[sid] -> set of (action, delivery_mode) scope keys
# See NousResearch/hermes-agent#67052 gap 4.
_approval_lock = threading.Lock()
_session_auto_approve: Dict[str, bool] = {}
_always_allow: Dict[str, set] = {}
def _get_backend() -> ComputerUseBackend:
global _backend
with _backend_lock:
if _backend is None:
backend_name = os.environ.get("HERMES_COMPUTER_USE_BACKEND", "cua").lower()
if backend_name in {"cua", "cua-driver", ""}:
from tools.computer_use.cua_backend import CuaDriverBackend
_backend = CuaDriverBackend()
elif backend_name == "noop": # pragma: no cover
_backend = _NoopBackend()
else:
raise RuntimeError(f"Unknown HERMES_COMPUTER_USE_BACKEND={backend_name!r}")
try:
_backend.start()
except Exception:
# Don't cache a backend whose start() failed (e.g. a lazy
# dependency install was declined / failed). The next call
# retries cleanly instead of returning a half-initialised
# backend.
_backend = None
raise
return _backend
def _shutdown_backend_atexit() -> None:
"""Stop the cached backend so the cua-driver child doesn't outlive us.
The backend is cached per-process and holds a long-lived ``cua-driver``
subprocess, so without this the driver survives the Hermes process that
spawned it (#28152 item 3). #69903 kept the orphan from burning a core by
disabling the cursor overlay; the process itself still lingered.
Mirrors ``browser_tool``'s ``atexit.register(_emergency_cleanup_all_sessions)``
— same spawn-and-drive-a-subprocess shape. atexit only, no signal handlers:
a ``SystemExit`` raised from a prompt_toolkit key binding corrupts its
coroutine state and makes the process unkillable. Never raises, since an
exception escaping atexit prints a traceback on every exit.
"""
global _backend
# Drop the lock before stop() — teardown budgets 5s and shouldn't block
# an unrelated caller waiting to spawn.
with _backend_lock:
backend, _backend = _backend, None
if backend is None:
return
try:
backend.stop()
except Exception as e:
logger.debug("cua-driver atexit teardown failed: %s", e)
atexit.register(_shutdown_backend_atexit)
def reset_backend_for_tests() -> None: # pragma: no cover
"""Test helper — tear down the cached backend and per-session state."""
_shutdown_backend_atexit()
_AUX_VISION_ROUTE_CACHE.clear()
with _approval_lock:
_session_auto_approve.clear()
_always_allow.clear()
class _NoopBackend(ComputerUseBackend): # pragma: no cover
"""Test/CI stub. Records calls; returns trivial results."""
def __init__(self) -> None:
self.calls: List[Tuple[str, Dict[str, Any]]] = []
self._started = False
def start(self) -> None: self._started = True
def stop(self) -> None: self._started = False
def is_available(self) -> bool: return True
def capture(
self,
mode: str = "som",
app: Optional[str] = None,
pid: Optional[int] = None,
window_id: Optional[int] = None,
) -> CaptureResult:
self.calls.append((
"capture",
{"mode": mode, "app": app, "pid": pid, "window_id": window_id},
))
return CaptureResult(mode=mode, width=1024, height=768, png_b64=None,
elements=[], app=app or "", window_title="")
def click(self, **kw) -> ActionResult:
self.calls.append(("click", kw))
return ActionResult(ok=True, action="click")
def drag(self, **kw) -> ActionResult:
self.calls.append(("drag", kw))
return ActionResult(ok=True, action="drag")
def scroll(self, **kw) -> ActionResult:
self.calls.append(("scroll", kw))
return ActionResult(ok=True, action="scroll")
def type_text(self, text: str, **kw) -> ActionResult:
self.calls.append(("type", {"text": text, **kw}))
return ActionResult(ok=True, action="type")
def key(self, keys: str, **kw) -> ActionResult:
self.calls.append(("key", {"keys": keys, **kw}))
return ActionResult(ok=True, action="key")
def list_apps(self) -> List[Dict[str, Any]]:
self.calls.append(("list_apps", {}))
return []
def list_windows(self) -> List[Dict[str, Any]]:
self.calls.append(("list_windows", {}))
return []
def focus_app(self, app: str, raise_window: bool = False) -> ActionResult:
self.calls.append(("focus_app", {"app": app, "raise": raise_window}))
return ActionResult(ok=True, action="focus_app")
def set_value(self, value: str, element: Optional[int] = None) -> ActionResult:
self.calls.append(("set_value", {"value": value, "element": element}))
return ActionResult(ok=True, action="set_value")
# ---------------------------------------------------------------------------
# Dispatch
# ---------------------------------------------------------------------------
def handle_computer_use(args: Dict[str, Any], **kwargs) -> Any:
"""Main entry point — dispatched by tools.registry.
Returns either a JSON string (text-only) or a dict marked `_multimodal`
(image + summary) which run_agent.py wraps into the tool message.
"""
action = (args.get("action") or "").strip().lower()
if not action:
return json.dumps({"error": "missing `action`"})
# Per-run key for approval-state isolation across concurrent sessions.
session_id = str(kwargs.get("session_id") or "")
# Safety: validate actions before approval prompt.
if action == "type":
text = args.get("text", "")
pat = _is_blocked_type(text)
if pat:
return json.dumps({
"error": f"blocked pattern in type text: {pat!r}",
"hint": "Dangerous shell patterns cannot be typed via computer_use.",
})
if action == "key":
keys = args.get("keys", "")
combo = _canon_key_combo(keys)
for blocked in _BLOCKED_KEY_COMBOS:
if blocked.issubset(combo) and len(blocked) <= len(combo):
return json.dumps({
"error": f"blocked key combo: {sorted(blocked)}",
"hint": "Destructive system shortcuts are hard-blocked.",
})
# Approval gate (destructive actions only).
if action in _DESTRUCTIVE_ACTIONS:
err = _request_approval(action, args, session_id)
if err is not None:
return err
# Dispatch to backend.
try:
backend = _get_backend()
except Exception as e:
return json.dumps({
"error": f"computer_use backend unavailable: {e}",
"hint": "If the cua-driver binary is missing, run `hermes computer-use install`. "
"If a Python dependency is missing, the error above shows the exact install command.",
})
try:
return _dispatch(backend, action, args)
except Exception as e:
logger.exception("computer_use %s failed", action)
return json.dumps({"error": f"{action} failed: {e}"})
def _request_approval(action: str, args: Dict[str, Any],
session_id: str = "") -> Optional[str]:
"""Return None if approved, or a JSON error string if denied.
Approval is scoped by (action, delivery_mode) AND by session_id.
Foreground delivery is a visible focus change, so a prior background
approval — even ``approve_session`` on the same action — must NOT
silently authorize it (NousResearch/hermes-agent#67052).
``always_approve`` (the blanket "auto-approve everything" unlock) still
covers foreground, since the user explicitly opted into unattended
operation. State is keyed on session_id so concurrent runs don't leak
unlocks into one another.
"""
is_foreground = args.get("delivery_mode") == "foreground"
scope_key = (action, "foreground" if is_foreground else "background")
with _approval_lock:
if _session_auto_approve.get(session_id):
return None
if scope_key in _always_allow.get(session_id, set()):
return None
cb = _approval_callback
if cb is None:
# No CLI approval wired — default allow. Gateway approval is handled
# one layer out via the normal tool-approval infra.
return None
summary = _summarize_action(action, args)
try:
verdict = cb(action, args, summary)
except Exception as e:
logger.warning("approval callback failed: %s", e)
verdict = "deny"
if verdict == "approve_once":
return None
if verdict == "approve_session" or verdict == "always_approve":
with _approval_lock:
_always_allow.setdefault(session_id, set()).add(scope_key)
if verdict == "always_approve":
_session_auto_approve[session_id] = True
return None
return json.dumps({"error": "denied by user", "action": action})
def _summarize_action(action: str, args: Dict[str, Any]) -> str:
fg = " [FOREGROUND — briefly raises the window / changes focus]" \
if args.get("delivery_mode") == "foreground" else ""
if action in {"click", "double_click", "right_click", "middle_click"}:
if args.get("element") is not None:
return f"{action} element #{args['element']}{fg}"
coord = args.get("coordinate")
if coord:
return f"{action} at {tuple(coord)}{fg}"
return action + fg
if action == "drag":
src = args.get("from_element") or args.get("from_coordinate")
dst = args.get("to_element") or args.get("to_coordinate")
return f"drag {src}{dst}{fg}"
if action == "scroll":
return f"scroll {args.get('direction', '?')} x{args.get('amount', 3)}{fg}"
if action == "type":
text = args.get("text", "")
return f"type {text[:60]!r}" + ("..." if len(text) > 60 else "") + fg
if action == "key":
return f"key {args.get('keys', '')!r}{fg}"
if action == "focus_app":
return f"focus {args.get('app', '')!r}" + (" (raise)" if args.get("raise_window") else "")
return action + fg
def _dispatch(backend: ComputerUseBackend, action: str, args: Dict[str, Any]) -> Any:
capture_after = bool(args.get("capture_after"))
if action == "capture":
mode = str(args.get("mode", "som"))
if mode not in {"som", "vision", "ax"}:
return json.dumps({"error": f"bad mode {mode!r}; use som|vision|ax"})
capture_kwargs: Dict[str, Any] = {"mode": mode, "app": args.get("app")}
if args.get("pid") is not None or args.get("window_id") is not None:
capture_kwargs.update({
"pid": args.get("pid"),
"window_id": args.get("window_id"),
})
cap = backend.capture(**capture_kwargs)
return _capture_response(cap, max_elements=_coerce_max_elements(args.get("max_elements")))
if action == "wait":
seconds = float(args.get("seconds", 1.0))
res = backend.wait(seconds)
return _text_response(res)
if action == "list_apps":
apps = backend.list_apps()
return json.dumps({"apps": apps, "count": len(apps)})
if action == "list_windows":
windows = backend.list_windows()
return json.dumps({"windows": windows, "count": len(windows)})
if action == "focus_app":
app = args.get("app")
if not app:
return json.dumps({"error": "focus_app requires `app`"})
res = backend.focus_app(app, raise_window=bool(args.get("raise_window")))
return _maybe_follow_capture(backend, res, capture_after)
# delivery_mode / bring_to_front thread through every input action so the
# model can escalate background → foreground per cua-driver's ladder.
delivery_mode = args.get("delivery_mode")
bring_to_front = bool(args.get("bring_to_front"))
if action in {"click", "double_click", "right_click", "middle_click"}:
button = args.get("button")
click_count = 1
if action == "double_click":
click_count = 2
elif action == "right_click":
button = "right"
elif action == "middle_click":
button = "middle"
else:
button = button or "left"
element = args.get("element")
coord = args.get("coordinate") or (None, None)
x, y = (coord[0], coord[1]) if coord and coord[0] is not None else (None, None)
res = backend.click(
element=element if element is not None else None,
x=x, y=y, button=button or "left", click_count=click_count,
modifiers=args.get("modifiers"),
delivery_mode=delivery_mode, bring_to_front=bring_to_front,
)
return _maybe_follow_capture(backend, res, capture_after)
if action == "drag":
has_elements = args.get("from_element") is not None and args.get("to_element") is not None
has_coords = args.get("from_coordinate") and args.get("to_coordinate")
if not has_elements and not has_coords:
return json.dumps({
"error": "drag requires from_coordinate/to_coordinate or from_element/to_element",
})
res = backend.drag(
from_element=args.get("from_element"),
to_element=args.get("to_element"),
from_xy=tuple(args["from_coordinate"]) if args.get("from_coordinate") else None,
to_xy=tuple(args["to_coordinate"]) if args.get("to_coordinate") else None,
button=args.get("button", "left"),
modifiers=args.get("modifiers"),
delivery_mode=delivery_mode, bring_to_front=bring_to_front,
)
return _maybe_follow_capture(backend, res, capture_after)
if action == "scroll":
coord = args.get("coordinate") or (None, None)
res = backend.scroll(
direction=args.get("direction", "down"),
amount=int(args.get("amount", 3)),
element=args.get("element"),
x=coord[0] if coord and coord[0] is not None else None,
y=coord[1] if coord and coord[1] is not None else None,
modifiers=args.get("modifiers"),
delivery_mode=delivery_mode, bring_to_front=bring_to_front,
)
return _maybe_follow_capture(backend, res, capture_after)
if action == "type":
res = backend.type_text(args.get("text", ""),
delivery_mode=delivery_mode, bring_to_front=bring_to_front)
return _maybe_follow_capture(backend, res, capture_after)
if action == "key":
res = backend.key(args.get("keys", ""),
delivery_mode=delivery_mode, bring_to_front=bring_to_front)
return _maybe_follow_capture(backend, res, capture_after)
if action == "set_value":
value = args.get("value")
if value is None:
return json.dumps({"error": "set_value requires `value`"})
res = backend.set_value(value=str(value), element=args.get("element"))
return _maybe_follow_capture(backend, res, capture_after)
return json.dumps({"error": f"unknown action {action!r}"})
# ---------------------------------------------------------------------------
# Response shaping
# ---------------------------------------------------------------------------
def _text_response(res: ActionResult) -> str:
payload: Dict[str, Any] = {"ok": res.ok, "action": res.action}
if res.message:
payload["message"] = res.message
# Surface cua-driver's structured verdict additively so the model can
# follow the verify → escalate ladder. Only include fields the driver
# actually returned (None = old driver / not carried). ok is transport
# success; effect/escalation are the semantic verdict.
if res.verified is not None:
payload["verified"] = res.verified
if res.effect is not None:
payload["effect"] = res.effect
if res.escalation is not None:
payload["escalation"] = res.escalation
if res.path is not None:
payload["path"] = res.path
if res.degraded is not None:
payload["degraded"] = res.degraded
if res.delivery_mode is not None:
payload["delivery_mode"] = res.delivery_mode
if res.code is not None:
payload["code"] = res.code
if res.meta:
payload["meta"] = res.meta
return json.dumps(payload)
# Default cap for the AX `elements` array returned by capture. Dense UIs
# (Electron apps, Obsidian, JetBrains IDEs) can publish 500+ AX nodes, which
# can exhaust session context after a single capture. The model-facing
# `max_elements` argument lets callers raise this when they need the full tree.
_DEFAULT_MAX_ELEMENTS = 100
# Hard upper bound on caller-supplied `max_elements`. Without this, a tool
# call passing a very large integer would silently disable the safeguard and
# reintroduce the original unbounded behavior.
_MAX_ALLOWED_MAX_ELEMENTS = 1000
_MIN_PROVIDER_IMAGE_DIMENSION = 8
def _image_dimensions_from_b64(image_b64: str) -> Optional[Tuple[int, int]]:
"""Return (width, height) for common inline screenshot formats.
Some providers reject images below 8x8 before the model sees the tool
result. Inspecting the encoded bytes here lets computer_use fall back to
its AX/SOM text payload instead of sending an unusable placeholder.
"""
if not image_b64:
return None
try:
raw = base64.b64decode(image_b64, validate=False)
except Exception:
return None
# PNG: signature + IHDR width/height.
if raw.startswith(b"\x89PNG\r\n\x1a\n") and len(raw) >= 24:
try:
width, height = struct.unpack(">II", raw[16:24])
return int(width), int(height)
except Exception:
return None
# JPEG: scan for SOF markers that carry dimensions.
if raw.startswith(b"\xff\xd8") and len(raw) > 4:
i = 2
while i + 9 < len(raw):
if raw[i] != 0xFF:
i += 1
continue
marker = raw[i + 1]
i += 2
while marker == 0xFF and i < len(raw):
marker = raw[i]
i += 1
if marker in {0xD8, 0xD9}:
continue
if marker == 0xDA:
break
if i + 2 > len(raw):
break
segment_len = int.from_bytes(raw[i:i + 2], "big")
if segment_len < 2 or i + segment_len > len(raw):
break
if marker in {
0xC0, 0xC1, 0xC2, 0xC3, 0xC5, 0xC6, 0xC7,
0xC9, 0xCA, 0xCB, 0xCD, 0xCE, 0xCF,
} and segment_len >= 7:
height = int.from_bytes(raw[i + 3:i + 5], "big")
width = int.from_bytes(raw[i + 5:i + 7], "big")
return int(width), int(height)
i += segment_len
return None
def _coerce_max_elements(value: Any) -> int:
"""Validate the caller-supplied ``max_elements``.
Falls back to :data:`_DEFAULT_MAX_ELEMENTS` for missing / non-integer /
sub-1 inputs so the cap can never be silently disabled by a malformed
tool-call argument. Clamps oversized values to
:data:`_MAX_ALLOWED_MAX_ELEMENTS` so a caller cannot bypass the
safeguard by passing a very large integer.
"""
if value is None:
return _DEFAULT_MAX_ELEMENTS
try:
n = int(value)
except (TypeError, ValueError):
return _DEFAULT_MAX_ELEMENTS
if n < 1:
return _DEFAULT_MAX_ELEMENTS
if n > _MAX_ALLOWED_MAX_ELEMENTS:
return _MAX_ALLOWED_MAX_ELEMENTS
return n
def _capture_response(cap: CaptureResult, max_elements: int = _DEFAULT_MAX_ELEMENTS) -> Any:
total_elements = len(cap.elements)
visible_elements = cap.elements[:max_elements]
truncated_elements = max(0, total_elements - len(visible_elements))
image_dimensions = _image_dimensions_from_b64(cap.png_b64 or "") if cap.png_b64 else None
response_width = image_dimensions[0] if image_dimensions else cap.width
response_height = image_dimensions[1] if image_dimensions else cap.height
image_too_small = bool(
image_dimensions
and (
image_dimensions[0] < _MIN_PROVIDER_IMAGE_DIMENSION
or image_dimensions[1] < _MIN_PROVIDER_IMAGE_DIMENSION
)
)
# Index only what's actually surfaced in the response — otherwise the
# human-readable summary references element indices the model cannot
# find in the JSON `elements` array (e.g. max_elements=10 vs the default
# 40-line index window).
element_index = _format_elements(visible_elements)
summary_lines = [
f"capture mode={cap.mode} {response_width}x{response_height}"
+ (f" app={cap.app}" if cap.app else "")
+ (f" window={cap.window_title!r}" if cap.window_title else ""),
f"{total_elements} interactable element(s):",
]
if element_index:
summary_lines.extend(element_index)
# Multimodal and AX paths both reference `summary`; build it once up-front
# so the aux-vision routing branch (which fires before either path is
# selected) has a valid value to hand to _route_capture_through_aux_vision.
# The AX path appends the "truncated to N of M" note to summary_lines
# below and rebuilds; the multimodal path keeps this version untouched.
if image_too_small:
summary_lines.append(
f" (screenshot omitted: {image_dimensions[0]}x{image_dimensions[1]} "
f"is below the {_MIN_PROVIDER_IMAGE_DIMENSION}x{_MIN_PROVIDER_IMAGE_DIMENSION} "
"provider minimum)"
)
summary = "\n".join(summary_lines)
if cap.png_b64 and cap.mode != "ax" and not image_too_small:
# Decide whether to hand the screenshot to the auxiliary.vision
# pipeline (text-only result) or keep the multimodal envelope (main
# model handles vision natively). Issue #24015: previously the
# multimodal envelope was returned unconditionally, so non-vision
# main models tripped HTTP 404 / 400 at the provider boundary even
# when auxiliary.vision was explicitly configured to handle this.
if _should_route_through_aux_vision():
routed = _route_capture_through_aux_vision(cap, summary)
if routed is not None:
return routed
# Aux routing was requested but failed (vision node down, aux call
# raised, empty analysis, etc.). Routing being requested means the
# main model may not be able to consume images; falling through to
# the multimodal envelope can break the capture with a provider
# error. Degrade to the AX/SOM text payload instead so element
# indices remain usable while vision is unavailable.
summary_lines.append(
" (vision unavailable: the auxiliary vision model could not "
"be reached; screenshot omitted. Element-index actions still "
"work — drive via the element list above.)"
)
if truncated_elements:
summary_lines.append(
f" (response truncated to {len(visible_elements)} of "
f"{total_elements} elements; raise max_elements or pass "
"app= to narrow)"
)
payload = {
"mode": cap.mode,
"width": response_width,
"height": response_height,
"app": cap.app,
"window_title": cap.window_title,
"elements": [_element_to_dict(e) for e in visible_elements],
"total_elements": total_elements,
"summary": "\n".join(summary_lines),
"vision_unavailable": True,
}
if truncated_elements:
payload["truncated_elements"] = truncated_elements
return json.dumps(payload)
# Prefer the explicit MIME type cua-driver attaches to its image
# parts (Surface 7 of NousResearch/hermes-agent#47072 — trycua/cua#1961
# made `mimeType` part of every MCP image-part response). Fall back
# to base64-prefix sniffing for older cua-driver builds that didn't
# carry the field. JPEG base64 starts with /9j/; PNG with iVBOR.
_mime = cap.image_mime_type
if not _mime:
_b64_prefix = cap.png_b64[:8]
_mime = "image/jpeg" if _b64_prefix.startswith("/9j/") else "image/png"
# The multimodal response carries the screenshot, not the AX
# elements array, so a "response truncated to N of M elements"
# note would be inaccurate — skip it on this branch.
return {
"_multimodal": True,
"content": [
{"type": "text", "text": summary},
{"type": "image_url",
"image_url": {"url": f"data:{_mime};base64,{cap.png_b64}"}},
],
"text_summary": summary,
"meta": {"mode": cap.mode, "width": response_width, "height": response_height,
"elements": total_elements, "png_bytes": cap.png_bytes_len},
}
# AX-only (or image-missing fallback): text path actually carries the
# `elements` array, so the truncation note applies here.
if truncated_elements:
summary_lines.append(
f" (response truncated to {len(visible_elements)} of {total_elements} elements; "
f"raise max_elements or pass app= to narrow)"
)
summary = "\n".join(summary_lines)
payload: Dict[str, Any] = {
"mode": cap.mode,
"width": response_width,
"height": response_height,
"app": cap.app,
"window_title": cap.window_title,
"elements": [_element_to_dict(e) for e in visible_elements],
"total_elements": total_elements,
"summary": summary,
}
if truncated_elements:
payload["truncated_elements"] = truncated_elements
return json.dumps(payload)
# ---------------------------------------------------------------------------
# auxiliary.vision routing for captured screenshots (#24015)
# ---------------------------------------------------------------------------
# Longest image side handed to the aux vision model. Full-resolution desktop
# captures tokenize heavily and can overflow small local-model context windows;
# ~1456px keeps SOM badges legible while cutting per-capture vision latency.
_MAX_VISION_DIM = 1456
def _shrink_capture_for_vision(raw: bytes, ext: str,
max_dim: int = _MAX_VISION_DIM) -> bytes:
"""Downscale encoded image bytes so the longest side is <= max_dim.
Returns the original bytes unchanged when the image already fits or when
Pillow is unavailable/fails — no worse than the pre-shrink behavior.
"""
try:
from io import BytesIO
from PIL import Image
img = Image.open(BytesIO(raw))
if max(img.size) <= max_dim:
return raw
img.thumbnail((max_dim, max_dim))
out = BytesIO()
img.save(out, format="JPEG" if ext == ".jpg" else "PNG")
return out.getvalue()
except Exception as exc:
logger.debug("computer_use: vision downscale skipped: %s", exc)
return raw
def _should_route_through_aux_vision() -> bool:
"""Return True when ``_capture_response`` should hand the PNG to aux vision.
Reads the active main provider/model and the loaded config and asks the
routing helper. Any failure (config import, runtime override missing,
etc.) returns False so the existing multimodal envelope continues to be
returned — fail open on the routing decision so a broken config can
never silently drop the screenshot for vision-capable main models.
"""
try:
from agent.auxiliary_client import _read_main_model, _read_main_provider
from hermes_cli.config import load_config
from tools.computer_use.vision_routing import (
should_route_capture_to_aux_vision,
)
except Exception as exc: # pragma: no cover - defensive
logger.debug("computer_use: aux-vision routing import failed: %s", exc)
return False
try:
provider = _read_main_provider() or ""
model = _read_main_model() or ""
except Exception as exc: # pragma: no cover - defensive
logger.debug("computer_use: aux-vision routing config read failed: %s", exc)
return False
cache_key = (str(provider), str(model))
cached = _AUX_VISION_ROUTE_CACHE.get(cache_key)
if cached is not None:
return cached
try:
cfg = load_config()
decision = bool(should_route_capture_to_aux_vision(provider, model, cfg))
except Exception as exc: # pragma: no cover - defensive
logger.debug("computer_use: aux-vision routing decision failed: %s", exc)
return False
_AUX_VISION_ROUTE_CACHE[cache_key] = decision
return decision
def _capture_after_mode() -> str:
"""Mode for ``capture_after`` follow-ups. Default ``som`` (screenshot)."""
try:
from hermes_cli.config import load_config
raw = ((load_config() or {}).get("computer_use") or {}).get(
"capture_after_mode", "som"
)
except Exception:
return "som"
mode = str(raw or "som").strip().lower()
return mode if mode in {"som", "vision", "ax"} else "som"
def _route_capture_through_aux_vision(
cap: CaptureResult,
summary: str,
) -> Optional[str]:
"""Pre-analyse the captured PNG via ``vision_analyze`` and return a text result.
The captured base64 PNG is materialised to ``$HERMES_HOME/cache/vision/``
and handed to ``vision_analyze_tool`` with a generic describe prompt.
The resulting text description is merged into the existing AX/SOM
summary so the main model receives a single text payload that mentions
every interactable element AND a description of what the screenshot
looked like.
Returns:
A JSON-encoded text response on success.
``None`` on failure (caller falls back to the multimodal envelope).
"""
if not cap.png_b64:
return None
try:
import base64 as _base64
import os as _os
import uuid as _uuid
from hermes_constants import get_hermes_dir
from model_tools import _run_async
from tools.vision_tools import vision_analyze_tool
except Exception as exc: # pragma: no cover - defensive
logger.debug("computer_use: aux-vision import failed: %s", exc)
return None
temp_image_path = None
try:
try:
raw = _base64.b64decode(cap.png_b64, validate=False)
except Exception as exc:
logger.debug("computer_use: failed to decode capture base64: %s", exc)
return None
# Pick an extension that matches the on-disk bytes so vision_analyze's
# MIME sniffing returns the right content-type.
# Surface 7: prefer the explicit MIME type cua-driver supplied.
_mime_for_ext = cap.image_mime_type or ""
if _mime_for_ext == "image/jpeg" or (not _mime_for_ext and cap.png_b64[:8].startswith("/9j/")):
ext = ".jpg"
else:
ext = ".png"
cache_dir = get_hermes_dir("cache/vision", "temp_vision_images")
cache_dir.mkdir(parents=True, exist_ok=True)
temp_image_path = cache_dir / f"computer_use_{_uuid.uuid4().hex}{ext}"
raw = _shrink_capture_for_vision(raw, ext)
temp_image_path.write_bytes(raw)
prompt = (
"Describe what is visible in this desktop application screenshot in "
"concise but specific terms. Mention the app name and window "
"title if visible, the overall layout, any labelled buttons, "
"menus or text fields, and any prominent text content the user "
"would need to know about. Do not invent details that are not "
"actually visible.\n\n"
f"AX/SOM index for cross-reference:\n{summary}"
)
result_json = _run_async(
vision_analyze_tool(str(temp_image_path), prompt)
)
except Exception as exc:
logger.warning(
"computer_use: auxiliary.vision pre-analysis failed (%s); "
"returning to caller without aux analysis",
exc,
)
return None
finally:
if temp_image_path is not None:
try:
_os.unlink(str(temp_image_path))
except Exception:
pass
analysis_text = ""
if isinstance(result_json, str):
try:
parsed = json.loads(result_json)
if isinstance(parsed, dict):
analysis_text = str(parsed.get("analysis") or "").strip()
except (TypeError, json.JSONDecodeError):
analysis_text = result_json.strip()
if not analysis_text:
return None
return json.dumps({
"mode": cap.mode,
"width": cap.width,
"height": cap.height,
"app": cap.app,
"window_title": cap.window_title,
"elements": [_element_to_dict(e) for e in cap.elements],
"summary": summary,
"vision_analysis": analysis_text,
"vision_analysis_routed_via": "auxiliary.vision",
})
def _maybe_follow_capture(
backend: ComputerUseBackend, res: ActionResult, do_capture: bool,
) -> Any:
if not do_capture:
return _text_response(res)
# Skip the follow-up capture when the action itself failed: showing a
# normal-looking screenshot after a failure misleads the model into thinking
# the action succeeded. Return the error text instead.
if not res.ok:
return _text_response(res)
try:
# Preserve the exact selected window when possible. Linux may expose a
# generic app name for several unrelated windows, so app-only recapture
# can silently switch targets after a successful action.
target = getattr(backend, "_last_target", None) or {}
pid = target.get("pid")
window_id = target.get("window_id")
mode = _capture_after_mode()
if pid is not None and window_id is not None:
cap = backend.capture(mode=mode, pid=pid, window_id=window_id)
else:
cap = backend.capture(mode=mode, app=getattr(backend, "_last_app", None))
except Exception as e:
logger.warning("follow-up capture failed: %s", e)
return _text_response(res)
# Combine action summary with the capture.
resp = _capture_response(cap)
if isinstance(resp, dict) and resp.get("_multimodal"):
prefix = f"[{res.action}] ok={res.ok}" + (f"{res.message}" if res.message else "")
resp["content"][0]["text"] = prefix + "\n\n" + resp["content"][0]["text"]
resp["text_summary"] = prefix + "\n\n" + resp["text_summary"]
return resp
# Fallback: action + text capture merged.
try:
data = json.loads(resp)
except (TypeError, json.JSONDecodeError):
data = {"capture": resp}
data["action"] = res.action
data["ok"] = res.ok
if res.message:
data["message"] = res.message
return json.dumps(data)
def _format_elements(elements: List[UIElement], max_lines: int = 40) -> List[str]:
out: List[str] = []
for e in elements[:max_lines]:
label = e.label.replace("\n", " ")[:60]
out.append(f" #{e.index} {e.role} {label!r} @ {e.bounds}"
+ (f" [{e.app}]" if e.app else ""))
if len(elements) > max_lines:
out.append(f" ... +{len(elements) - max_lines} more (call capture with app= to narrow)")
return out
def _element_to_dict(e: UIElement) -> Dict[str, Any]:
return {
"index": e.index,
"role": e.role,
"label": e.label,
"bounds": list(e.bounds),
"app": e.app,
}
# ---------------------------------------------------------------------------
# Availability check (used by the tool registry check_fn)
# ---------------------------------------------------------------------------
def check_computer_use_requirements() -> bool:
"""Return True iff computer_use can run on this host.
Conditions: macOS, Windows, or Linux + cua-driver binary installed (or
override via env). cua-driver runs on all three; the Linux path is
headed/X11 today (Wayland via XWayland), pure-Wayland progress tracked
upstream. Linux users see specific blocked checks via
`hermes computer-use doctor` if their session is incomplete (e.g. no
DISPLAY set).
"""
if sys.platform not in ("darwin", "win32", "linux"):
return False
from tools.computer_use.cua_backend import cua_driver_binary_available
return cua_driver_binary_available()
def get_computer_use_schema() -> Dict[str, Any]:
from tools.computer_use.schema import COMPUTER_USE_SCHEMA
return COMPUTER_USE_SCHEMA