hermes-agent/agent/image_routing.py
kshitij 2ec8d2b42f
chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937)
Replace  with  for all literal-tuple
membership tests. Set lookup is O(1) vs O(n) for tuple — consistent
micro-optimization across the codebase.

608 instances fixed via `ruff --fix --unsafe-fixes`, 0 remaining.
133 files, +626/-626 (net zero).
2026-05-11 11:13:25 -07:00

301 lines
11 KiB
Python

"""Routing helpers for inbound user-attached images.
Two modes:
native — attach images as OpenAI-style ``image_url`` content parts on the
user turn. Provider adapters (Anthropic, Gemini, Bedrock, Codex,
OpenAI chat.completions) already translate these into their
vendor-specific multimodal formats.
text — run ``vision_analyze`` on each image up-front and prepend the
description to the user's text. The model never sees the pixels;
it only sees a lossy text summary. This is the pre-existing
behaviour and still the right choice for non-vision models.
The decision is made once per message turn by :func:`decide_image_input_mode`.
It reads ``agent.image_input_mode`` from config.yaml (``auto`` | ``native``
| ``text``, default ``auto``) and the active model's capability metadata.
In ``auto`` mode:
- If the user has explicitly configured ``auxiliary.vision.provider``
(i.e. not ``auto`` and not empty), we assume they want the text pipeline
regardless of the main model — they've opted in to a specific vision
backend for a reason (cost, quality, local-only, etc.).
- Otherwise, if the active model reports ``supports_vision=True`` in its
models.dev metadata, we attach natively.
- Otherwise (non-vision model, no explicit override), we fall back to text.
This keeps ``vision_analyze`` surfaced as a tool in every session — skills
and agent flows that chain it (browser screenshots, deeper inspection of
URL-referenced images, style-gating loops) keep working. The routing only
affects *how user-attached images on the current turn* are presented to the
main model.
"""
from __future__ import annotations
import base64
import logging
import mimetypes
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple
logger = logging.getLogger(__name__)
_VALID_MODES = frozenset({"auto", "native", "text"})
def _coerce_mode(raw: Any) -> str:
"""Normalize a config value into one of the valid modes."""
if not isinstance(raw, str):
return "auto"
val = raw.strip().lower()
if val in _VALID_MODES:
return val
return "auto"
def _explicit_aux_vision_override(cfg: Optional[Dict[str, Any]]) -> bool:
"""True when the user configured a specific auxiliary vision backend.
An explicit override means the user *wants* the text pipeline (they're
paying for a dedicated vision model), so we don't silently bypass it.
"""
if not isinstance(cfg, dict):
return False
aux = cfg.get("auxiliary") or {}
if not isinstance(aux, dict):
return False
vision = aux.get("vision") or {}
if not isinstance(vision, dict):
return False
provider = str(vision.get("provider") or "").strip().lower()
model = str(vision.get("model") or "").strip()
base_url = str(vision.get("base_url") or "").strip()
# "auto" / "" / blank = not explicit
if provider in {"", "auto"} and not model and not base_url:
return False
return True
def _lookup_supports_vision(provider: str, model: str) -> Optional[bool]:
"""Return True/False if we can resolve caps, None if unknown."""
if not provider or not model:
return None
try:
from agent.models_dev import get_model_capabilities
caps = get_model_capabilities(provider, model)
except Exception as exc: # pragma: no cover - defensive
logger.debug("image_routing: caps lookup failed for %s:%s%s", provider, model, exc)
return None
if caps is None:
return None
return bool(caps.supports_vision)
def decide_image_input_mode(
provider: str,
model: str,
cfg: Optional[Dict[str, Any]],
) -> str:
"""Return ``"native"`` or ``"text"`` for the given turn.
Args:
provider: active inference provider ID (e.g. ``"anthropic"``, ``"openrouter"``).
model: active model slug as it would be sent to the provider.
cfg: loaded config.yaml dict, or None. When None, behaves as auto.
"""
mode_cfg = "auto"
if isinstance(cfg, dict):
agent_cfg = cfg.get("agent") or {}
if isinstance(agent_cfg, dict):
mode_cfg = _coerce_mode(agent_cfg.get("image_input_mode"))
if mode_cfg == "native":
return "native"
if mode_cfg == "text":
return "text"
# auto
if _explicit_aux_vision_override(cfg):
return "text"
supports = _lookup_supports_vision(provider, model)
if supports is True:
return "native"
return "text"
# Image size handling is REACTIVE rather than proactive: we attempt native
# attachment at full size regardless of provider, and rely on
# ``run_agent._try_shrink_image_parts_in_messages`` to shrink + retry if
# the provider rejects the request (e.g. Anthropic's hard 5 MB per-image
# ceiling returned as HTTP 400 "image exceeds 5 MB maximum").
#
# Why reactive: our knowledge of provider ceilings is partial and evolving
# (OpenAI accepts 49 MB+, Anthropic 5 MB, Gemini 100 MB, others unknown).
# A proactive per-provider table would be stale the moment a provider raises
# or lowers its limit, and silently degrading quality for users on providers
# that would have accepted the full image is the worse failure mode.
# The shrink-on-reject path loses 1 API call + maybe 1s of Pillow work when
# it fires, which is cheaper than permanent quality loss.
def _sniff_mime_from_bytes(raw: bytes) -> Optional[str]:
"""Detect image MIME from magic bytes. Returns None if unrecognised.
Filename-based detection (``mimetypes.guess_type``) is unreliable when
upstream platforms lie about content-type. Discord, for example, can
serve a PNG with ``content_type=image/webp`` for proxied/animated
stickers, custom emoji previews, or images uploaded via certain bots.
Anthropic strictly validates that declared media_type matches the
actual bytes and returns HTTP 400 on mismatch, so we sniff to be safe.
"""
if not raw:
return None
# PNG: 89 50 4E 47 0D 0A 1A 0A
if raw.startswith(b"\x89PNG\r\n\x1a\n"):
return "image/png"
# JPEG: FF D8 FF
if raw.startswith(b"\xff\xd8\xff"):
return "image/jpeg"
# GIF87a / GIF89a
if raw[:6] in {b"GIF87a", b"GIF89a"}:
return "image/gif"
# WEBP: "RIFF" .... "WEBP"
if len(raw) >= 12 and raw[:4] == b"RIFF" and raw[8:12] == b"WEBP":
return "image/webp"
# BMP: "BM"
if raw.startswith(b"BM"):
return "image/bmp"
# HEIC/HEIF: ftypheic / ftypheix / ftypmif1 / ftypmsf1 etc.
if len(raw) >= 12 and raw[4:8] == b"ftyp" and raw[8:12] in {
b"heic", b"heix", b"hevc", b"hevx", b"mif1", b"msf1", b"heim", b"heis",
}:
return "image/heic"
return None
def _guess_mime(path: Path, raw: Optional[bytes] = None) -> str:
"""Return image MIME type for *path*.
If *raw* bytes are provided, magic-byte sniffing wins (authoritative).
Otherwise we fall back to ``mimetypes`` then suffix-based defaults.
"""
if raw is not None:
sniffed = _sniff_mime_from_bytes(raw)
if sniffed:
return sniffed
mime, _ = mimetypes.guess_type(str(path))
if mime and mime.startswith("image/"):
return mime
# mimetypes on some Linux distros mis-maps .jpg; default to jpeg when
# the suffix looks imagey.
suffix = path.suffix.lower()
return {
".jpg": "image/jpeg",
".jpeg": "image/jpeg",
".png": "image/png",
".gif": "image/gif",
".webp": "image/webp",
".bmp": "image/bmp",
}.get(suffix, "image/jpeg")
def _file_to_data_url(path: Path) -> Optional[str]:
"""Encode a local image as a base64 data URL at its native size.
Size limits are NOT enforced here — the agent retry loop
(``run_agent._try_shrink_image_parts_in_messages``) shrinks on the
provider's first rejection. Keeping this simple means providers that
accept large images (OpenAI 49 MB+, Gemini 100 MB) don't pay a silent
quality tax just because one other provider is stricter.
Returns None only if the file can't be read (missing, permission
denied, etc.); the caller reports those paths in ``skipped``.
"""
try:
raw = path.read_bytes()
except Exception as exc:
logger.warning("image_routing: failed to read %s%s", path, exc)
return None
mime = _guess_mime(path, raw=raw)
b64 = base64.b64encode(raw).decode("ascii")
return f"data:{mime};base64,{b64}"
def build_native_content_parts(
user_text: str,
image_paths: List[str],
) -> Tuple[List[Dict[str, Any]], List[str]]:
"""Build an OpenAI-style ``content`` list for a user turn.
Shape:
[{"type": "text", "text": "...\\n\\n[Image attached at: /local/path]"},
{"type": "image_url", "image_url": {"url": "data:image/png;base64,..."}},
...]
The local path of each successfully attached image is appended to the
text part as ``[Image attached at: <path>]``. The model still sees the
pixels via the ``image_url`` part (full native vision); the path note
just gives it a string handle so MCP/skill tools that take an image
path or URL argument can be invoked on the same image without an
extra round-trip. This parallels the text-mode hint produced by
``Runner._enrich_message_with_vision`` (``vision_analyze using image_url:
<path>``) so behaviour is consistent across both image input modes.
Images are attached at their native size. If a provider rejects the
request because an image is too large (e.g. Anthropic's 5 MB per-image
ceiling), the agent's retry loop transparently shrinks and retries
once — see ``run_agent._try_shrink_image_parts_in_messages``.
Returns (content_parts, skipped_paths). Skipped paths are files that
couldn't be read from disk and are NOT advertised in the path hints.
"""
skipped: List[str] = []
image_parts: List[Dict[str, Any]] = []
attached_paths: List[str] = []
for raw_path in image_paths:
p = Path(raw_path)
if not p.exists() or not p.is_file():
skipped.append(str(raw_path))
continue
data_url = _file_to_data_url(p)
if not data_url:
skipped.append(str(raw_path))
continue
image_parts.append({
"type": "image_url",
"image_url": {"url": data_url},
})
attached_paths.append(str(raw_path))
text = (user_text or "").strip()
# If at least one image attached, build a single text part that combines
# the user's caption (or a neutral default) with one path hint per image.
if attached_paths:
base_text = text or "What do you see in this image?"
path_hints = "\n".join(
f"[Image attached at: {p}]" for p in attached_paths
)
combined_text = f"{base_text}\n\n{path_hints}"
parts: List[Dict[str, Any]] = [{"type": "text", "text": combined_text}]
parts.extend(image_parts)
return parts, skipped
# No images successfully attached — fall back to plain text-only behaviour.
parts = []
if text:
parts.append({"type": "text", "text": text})
return parts, skipped
__all__ = [
"decide_image_input_mode",
"build_native_content_parts",
]