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hermes-agent/plugins/image_gen/openai-codex/__init__.py
T

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Python

"""OpenAI image generation backend — ChatGPT/Codex OAuth variant.
Same model catalog and tier semantics as the ``openai`` plugin (``gpt-image-2``
at low/medium/high quality), but routed through the Codex Responses API
``image_generation`` tool instead of ``images.generate``, so users already
authenticated with Codex/ChatGPT need no separate ``OPENAI_API_KEY``.
Tier precedence: ``OPENAI_IMAGE_MODEL`` env → ``image_gen.openai-codex.model``
→ ``image_gen.model`` (when it's one of our tier IDs) → :data:`DEFAULT_MODEL`.
Output is saved as PNG under ``$HERMES_HOME/cache/images/``; source images for
editing are sent as Responses ``input_image`` content parts.
Do NOT reintroduce an "account capability" classifier keyed on ``Tool choice
'image_generation' not found in 'tools' parameter``: that HTTP 400 is a
request-shape rejection emitted for every account (the Codex backend resolves
tool_choice as a function-tool name), not an entitlement problem. It is fixed
by omitting tool_choice (see ``_build_responses_payload``); any remaining HTTP
error must surface verbatim so it stays diagnosable.
"""
from __future__ import annotations
import base64
import json
import logging
import os
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple
from agent.image_gen_provider import (
DEFAULT_ASPECT_RATIO,
ImageGenProvider,
resolve_aspect_ratio,
save_b64_image,
success_response,
)
from plugins.image_gen._common import (
GPT_IMAGE_2_API_MODEL as API_MODEL,
GPT_IMAGE_2_DEFAULT as DEFAULT_MODEL,
GPT_IMAGE_2_TIERS,
catalog_rows,
collect_source_images,
error_factory,
prompt_required_error,
resolve_static_model,
size_for,
)
logger = logging.getLogger(__name__)
_MAX_ERROR_BODY_CHARS = 500
_MODELS: Dict[str, Dict[str, Any]] = dict(GPT_IMAGE_2_TIERS)
# Codex Responses surface used for the request. The chat model only hosts the
# ``image_generation`` tool call; the image work is done by ``API_MODEL``.
_CODEX_CHAT_MODEL = "gpt-5.5"
_CODEX_BASE_URL = "https://chatgpt.com/backend-api/codex"
_CODEX_INSTRUCTIONS = (
"You are an assistant that must fulfill image generation and image editing "
"requests by using the image_generation tool when provided."
)
_MAX_REFERENCE_IMAGES = 16
_MAX_INPUT_IMAGE_BYTES = 25 * 1024 * 1024
# gpt-image-2's ``input_image`` accepts raster formats only. The shared sniffer
# also recognizes SVG/TIFF/ICO, which the API rejects server-side — gate to this
# allowlist so unsupported inputs fail locally instead of as an opaque HTTP 400.
_ACCEPTED_INPUT_MIME = frozenset({"image/png", "image/jpeg", "image/gif", "image/webp"})
# Progressive preview frames (partial_image_b64) are intermediate renders;
# saving them as finals produced the "smear" failure mode. Defense in depth:
# request 0 partials, never let a partial overwrite a final in the extractor,
# and only deliver source=final from generate(). Live streams may still emit a
# partial event even with 0 — fine as long as only a final ``result`` is saved.
_PARTIAL_IMAGES_REQUESTED = 0
# Content-agnostic retries when the stream yields no final result.
_NONFINAL_RETRIES = 1
_NO_AUTH = (
"No Codex/ChatGPT OAuth credentials available. Run "
"`hermes auth codex` (or `hermes setup` → Codex) to sign in."
)
def _summarize_error_body(body: str) -> str:
"""Bounded error summary preferring parsed ``error.message``.
A blind head-truncation of the raw body can cut the actual message off —
Codex error payloads sometimes carry hundreds of bytes of leading metadata.
"""
text = body or ""
try:
payload = json.loads(text)
error = payload.get("error") if isinstance(payload, dict) else None
message = error.get("message") if isinstance(error, dict) else None
if isinstance(message, str) and message.strip():
return message.strip()[:_MAX_ERROR_BODY_CHARS]
except (TypeError, ValueError):
pass
return text[:_MAX_ERROR_BODY_CHARS]
def _resolve_model() -> Tuple[str, Dict[str, Any]]:
"""Decide which tier to use and return ``(model_id, meta)``."""
return resolve_static_model(
_MODELS, DEFAULT_MODEL, env_var="OPENAI_IMAGE_MODEL", config_key="openai-codex"
)
def _read_codex_access_token() -> Optional[str]:
"""Usable Codex OAuth token or None; the canonical reader in
``agent.auxiliary_client`` owns expiry, pool selection and JWT decoding."""
try:
from agent.auxiliary_client import _read_codex_access_token as _reader
token = _reader()
if isinstance(token, str) and token.strip():
return token.strip()
return None
except Exception as exc:
logger.debug("Could not resolve Codex access token: %s", exc)
return None
def _sniff_image_mime(raw: bytes) -> Optional[str]:
"""Raster MIME from magic bytes (shared sniffer), gated to :data:`_ACCEPTED_INPUT_MIME`."""
from agent.image_routing import _sniff_mime_from_bytes
mime = _sniff_mime_from_bytes(raw)
return mime if mime in _ACCEPTED_INPUT_MIME else None
def _encode_input_image(raw: bytes, too_big: str, unsupported: str) -> str:
"""Size- and MIME-check raw image bytes, then return a canonical ``data:`` URL."""
if len(raw) > _MAX_INPUT_IMAGE_BYTES:
raise ValueError(too_big)
mime = _sniff_image_mime(raw)
if mime is None:
raise ValueError(unsupported)
return f"data:{mime};base64,{base64.b64encode(raw).decode('ascii')}"
def _data_url_to_input_image_url(value: str) -> str:
"""Validate and canonicalize a data:image URL for Responses input_image."""
if "," not in value:
raise ValueError("Image data URL is missing a comma separator")
header, data = value.split(",", 1)
header_lc = header.lower()
if not header_lc.startswith("data:image/") or ";base64" not in header_lc:
raise ValueError("Only base64 data:image URLs are supported as Codex image inputs")
return _encode_input_image(
base64.b64decode(data, validate=True),
"Image data URL exceeds 25MB cap",
"Image data URL does not contain supported image bytes",
)
def _local_image_to_data_url(value: str) -> str:
"""Read a local image path and return a validated data:image URL."""
try:
from agent.file_safety import get_read_block_error
blocked = get_read_block_error(value)
if blocked:
raise ValueError(blocked)
except ValueError:
raise
except Exception as exc:
logger.debug("Codex image input read guard unavailable: %s", exc)
path = Path(os.path.expanduser(value)).resolve()
if not path.is_file():
raise ValueError(f"Image input path does not exist or is not a file: {value}")
if path.stat().st_size <= 0:
raise ValueError(f"Image input path is empty: {value}")
return _encode_input_image(
path.read_bytes(),
f"Image input path exceeds 25MB cap: {value}",
f"Image input path is not a supported image: {value}",
)
def _to_input_image_part(value: str) -> Dict[str, str]:
"""Convert a URL/data URL/local path into a Responses input_image part."""
candidate = (value or "").strip()
if not candidate:
raise ValueError("Blank image input")
lowered = candidate.lower()
if lowered.startswith(("http://", "https://")):
image_url = candidate
elif lowered.startswith("data:"):
image_url = _data_url_to_input_image_url(candidate)
else:
image_url = _local_image_to_data_url(candidate)
return {"type": "input_image", "image_url": image_url}
def _normalize_input_images(
image_url: Optional[str],
reference_image_urls: Optional[List[str]],
) -> List[Dict[str, str]]:
"""Collect primary + reference images as ordered Responses content parts."""
values = collect_source_images(image_url, reference_image_urls, limit=_MAX_REFERENCE_IMAGES)
return [_to_input_image_part(value) for value in values]
def _build_responses_payload(
*,
prompt: str,
size: str,
quality: str,
input_images: Optional[List[Dict[str, str]]] = None,
) -> Dict[str, Any]:
"""Build the Codex Responses request body for an image_generation call.
No ``tool_choice`` is sent: the Codex backend rejects every shape for
forcing the hosted ``image_generation`` tool (it looks tool_choice up as a
*function* name), so letting the host model decide — nudged by
``instructions`` — is the only accepted shape.
"""
content: List[Dict[str, Any]] = [{"type": "input_text", "text": prompt}]
if input_images:
content.extend(input_images)
return {
"model": _CODEX_CHAT_MODEL,
"store": False,
"instructions": _CODEX_INSTRUCTIONS,
"input": [{"type": "message", "role": "user", "content": content}],
"tools": [{
"type": "image_generation",
"model": API_MODEL,
"size": size,
"quality": quality,
"output_format": "png",
"background": "opaque",
"partial_images": _PARTIAL_IMAGES_REQUESTED,
}],
"stream": True,
}
def _extract_image_candidates(value: Any) -> Tuple[Optional[str], Optional[str]]:
"""Return ``(final_result_b64, latest_partial_b64)`` from a payload tree.
Tracked separately so a partial can never overwrite a genuine final, even
when both coexist in the same event payload.
"""
result_b64: Optional[str] = None
partial_b64: Optional[str] = None
def walk(node: Any) -> None:
nonlocal result_b64, partial_b64
if isinstance(node, dict):
if node.get("type") == "image_generation_call":
result = node.get("result")
if isinstance(result, str) and result:
result_b64 = result
partial = node.get("partial_image_b64")
if isinstance(partial, str) and partial:
partial_b64 = partial
for child in node.values():
walk(child)
elif isinstance(node, list):
for child in node:
walk(child)
walk(value)
return result_b64, partial_b64
def _extract_image_b64(value: Any) -> Optional[str]:
"""Image b64 from a payload, preferring a final result over a partial."""
result_b64, partial_b64 = _extract_image_candidates(value)
return result_b64 or partial_b64
def _png_pixel_size(raw: bytes) -> Optional[str]:
"""Return ``"{w}x{h}"`` for a PNG payload, or None if not a PNG IHDR."""
import struct
if len(raw) < 24 or raw[:8] != b"\x89PNG\r\n\x1a\n" or raw[12:16] != b"IHDR":
return None
width, height = struct.unpack(">II", raw[16:24])
return f"{width}x{height}"
def _iter_sse_json(response: Any):
"""Yield JSON payloads from an SSE response without OpenAI SDK parsing.
The Codex backend can emit image-generation events newer than the pinned
SDK understands; raw SSE parsing stays tolerant of those shape changes.
"""
event_name: Optional[str] = None
data_lines: List[str] = []
def flush():
nonlocal event_name, data_lines
if not data_lines:
event_name = None
return None
raw = "\n".join(data_lines).strip()
event = event_name
event_name = None
data_lines = []
if not raw or raw == "[DONE]":
return None
payload = json.loads(raw)
if isinstance(payload, dict) and event and "type" not in payload:
payload["type"] = event
return payload
for line in response.iter_lines():
if isinstance(line, bytes):
line = line.decode("utf-8", errors="replace")
line = str(line)
if line == "":
payload = flush()
if payload is not None:
yield payload
continue
if line.startswith(":"):
continue
if line.startswith("event:"):
event_name = line[len("event:"):].strip()
elif line.startswith("data:"):
data_lines.append(line[len("data:"):].lstrip())
payload = flush()
if payload is not None:
yield payload
def _collect_image_b64(
token: str,
*,
prompt: str,
size: str,
quality: str,
input_images: Optional[List[Dict[str, str]]] = None,
) -> Optional[Dict[str, str]]:
"""Stream a Codex Responses image_generation call.
Returns ``{"b64": ..., "source": "final"|"partial"}`` or ``None``. A
progressive partial is retained only when no final result ever arrives;
callers must not treat partial-only as success.
"""
import httpx
from agent.codex_headers import codex_cloudflare_headers
headers = codex_cloudflare_headers(token)
headers.update({
"Accept": "text/event-stream",
"Authorization": f"Bearer {token}",
"Content-Type": "application/json",
})
payload = _build_responses_payload(
prompt=prompt, size=size, quality=quality, input_images=input_images,
)
timeout = httpx.Timeout(300.0, connect=30.0, read=300.0, write=30.0, pool=30.0)
final_b64: Optional[str] = None
partial_b64: Optional[str] = None
with httpx.Client(timeout=timeout, headers=headers) as http:
with http.stream("POST", f"{_CODEX_BASE_URL}/responses", json=payload) as response:
try:
response.raise_for_status()
except httpx.HTTPStatusError as exc:
exc.response.read()
raise RuntimeError(
f"Codex Responses API returned HTTP {exc.response.status_code}: "
f"{_summarize_error_body(exc.response.text)}"
) from exc
for event in _iter_sse_json(response):
result_b64, event_partial = _extract_image_candidates(event)
if result_b64:
final_b64 = result_b64
if event_partial:
partial_b64 = event_partial
if final_b64:
return {"b64": final_b64, "source": "final"}
if partial_b64:
return {"b64": partial_b64, "source": "partial"}
return None
class OpenAICodexImageGenProvider(ImageGenProvider):
"""gpt-image-2 routed through ChatGPT/Codex OAuth instead of an API key."""
@property
def name(self) -> str:
return "openai-codex"
@property
def display_name(self) -> str:
return "OpenAI (Codex auth)"
def is_available(self) -> bool:
if not _read_codex_access_token():
return False
try:
import httpx # noqa: F401
except ImportError:
return False
return True
def list_models(self) -> List[Dict[str, Any]]:
return catalog_rows(_MODELS, price="varies")
def default_model(self) -> Optional[str]:
return DEFAULT_MODEL
def get_setup_schema(self) -> Dict[str, Any]:
return {
"name": "OpenAI (Codex auth)",
"badge": "free",
"tag": "gpt-image-2 via ChatGPT/Codex OAuth — no API key required; supports text and image inputs",
"env_vars": [],
"post_setup_hint": (
"Sign in with `hermes auth codex` (or `hermes setup` → Codex) "
"if you haven't already. No API key needed."
),
}
def capabilities(self) -> Dict[str, Any]:
# Source/reference images travel as `input_image` content parts; keep
# this honest so the dynamic schema encourages identity-preserving edits.
return {"modalities": ["text", "image"], "max_reference_images": _MAX_REFERENCE_IMAGES}
def generate(
self,
prompt: str,
aspect_ratio: str = DEFAULT_ASPECT_RATIO,
*,
image_url: Optional[str] = None,
reference_image_urls: Optional[List[str]] = None,
**kwargs: Any,
) -> Dict[str, Any]:
prompt = (prompt or "").strip()
aspect = resolve_aspect_ratio(aspect_ratio)
if not prompt:
return prompt_required_error("openai-codex", aspect)
token = _read_codex_access_token()
if not token:
return error_factory("openai-codex", aspect)(_NO_AUTH, "auth_required")
try:
import httpx # noqa: F401
except ImportError:
return error_factory("openai-codex", aspect)(
"httpx Python package not installed (pip install httpx)", "missing_dependency"
)
tier_id, meta = _resolve_model()
size = size_for(aspect)
fail = error_factory("openai-codex", aspect, model=tier_id, prompt=prompt)
attempts = _NONFINAL_RETRIES + 1
try:
input_images = _normalize_input_images(image_url, reference_image_urls)
except Exception as exc:
return fail(f"Invalid image input for Codex image editing: {exc}", "invalid_image_input")
try:
collected: Optional[Dict[str, str]] = None
for attempt in range(attempts):
collected = _collect_image_b64(
token, prompt=prompt, size=size, quality=meta["quality"],
input_images=input_images or None,
)
if collected and collected.get("source") == "final" and collected.get("b64"):
break
if attempt < _NONFINAL_RETRIES:
kind = (
"progressive-only partial frame"
if collected and collected.get("source") == "partial"
else "no image_generation_call result"
)
logger.warning(
"Codex image stream ended with %s (attempt %s/%s); "
"retrying once before failing closed.",
kind, attempt + 1, attempts,
)
except Exception as exc:
logger.debug("Codex image generation failed", exc_info=True)
return fail(f"OpenAI image generation via Codex auth failed: {exc}", "api_error")
if not collected or not collected.get("b64"):
return fail(
f"Codex response contained no image_generation_call result after {attempts} attempt(s)",
"empty_response",
)
image_source = collected.get("source") or "unknown"
b64 = collected["b64"]
# Never deliver a progressive-only frame as success (smeared previews).
if image_source != "final":
try:
pixel_hint = _png_pixel_size(base64.b64decode(b64, validate=False))
except Exception:
pixel_hint = None
detail = (
"Codex returned only a progressive partial image frame after "
f"{attempts} attempt(s); refusing to save it as a final deliverable."
)
if pixel_hint:
detail = f"{detail} partial_pixel_size={pixel_hint}."
err = fail(detail, "incomplete_image")
err["image_source"] = image_source
err["requested_size"] = size
err["partial_pixel_size"] = pixel_hint
err["nonfinal_retries"] = _NONFINAL_RETRIES
return err
try:
pixel_size = _png_pixel_size(base64.b64decode(b64))
saved_path = save_b64_image(b64, prefix=f"openai_codex_{tier_id}")
except Exception as exc:
return fail(f"Could not save image to cache: {exc}", "io_error")
return success_response(
image=str(saved_path),
model=tier_id,
prompt=prompt,
aspect_ratio=aspect,
provider="openai-codex",
modality="image" if input_images else "text",
extra={
"size": size,
"quality": meta["quality"],
"input_image_count": len(input_images),
"image_source": image_source,
"requested_size": size,
"pixel_size": pixel_size,
},
)
def register(ctx) -> None:
"""Plugin entry point — register the Codex-backed image-gen provider."""
ctx.register_image_gen_provider(OpenAICodexImageGenProvider())