codex-shim-byok-models

codex-shim --help

{
  "customModels": [
    {
      "model": "gpt-5.5",
      "provider": "openai",
      "baseUrl": "https://api.openai.com/v1",
      "apiKey": "${OPENAI_API_KEY}",
      "displayName": "OpenAI GPT-5.5",
      "maxContextLimit": 400000
    },
    {
      "model": "claude-opus-4-7-20251109",
      "provider": "anthropic",
      "baseUrl": "https://api.anthropic.com/v1",
      "apiKey": "${ANTHROPIC_API_KEY}",
      "displayName": "Claude Opus 4.7"
    },
    {
      "model": "deepseek-v4-pro",
      "provider": "anthropic",
      "baseUrl": "https://api.deepseek.com/anthropic",
      "apiKey": "${DEEPSEEK_API_KEY}",
      "displayName": "DeepSeek V4 Pro",
      "noImageSupport": true
    }
  ]
}

codex-shim --settings /path/to/custom-models.json generate
codex-shim --settings /path/to/custom-models.json start

export OPENAI_API_KEY="sk-..."
export ANTHROPIC_API_KEY="sk-ant-..."
export DEEPSEEK_API_KEY="..."

codex-shim generate

# Start shim on 127.0.0.1:8765
codex-shim start
 
# Check status
codex-shim status
 
# Stop daemon
codex-shim stop
 
# Restart
codex-shim restart

# Show all generated slugs and upstream routes
codex-shim list
 
# Show models currently in Codex Desktop picker
codex-model list

# Launch with shim wired in (doesn't modify ~/.codex/config.toml)
codex-app
 
# Launch and open specific path
codex-app /path/to/project
 
# Equivalent long form
codex-shim app /path/to/project

# List available slugs
codex-model list
 
# Set default model for next launch
codex-model openai-gpt-5-5
 
# Relaunch Codex
codex-app

codex-shim codex -- chat "explain this code"
codex-shim codex -- edit main.py "add error handling"

Codex Desktop → /v1/responses → codex-shim (127.0.0.1:8765)
                                   ┃
                    ┏━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━┓
                    ┃              ┃              ┃
         slug "openai-gpt-5-5"    provider       provider
                    ┃            "openai"      "anthropic"
                    ┃              ┃              ┃
         chatgpt.com/backend-api  baseUrl/       baseUrl/
         /codex/responses         chat/          messages
         (Bearer token)           completions    (x-api-key)

# codex_shim/translator.py example pattern
 
async def translate_to_openai(responses_request):
    """Convert Codex Responses API → OpenAI chat completions."""
    return {
        "model": responses_request["model"],
        "messages": responses_request["messages"],
        "stream": True,
        "temperature": responses_request.get("temperature", 1.0),
        "max_tokens": responses_request.get("max_tokens"),
    }
 
async def translate_to_anthropic(responses_request):
    """Convert Codex Responses API → Anthropic messages."""
    messages = []
    system = None
    
    for msg in responses_request["messages"]:
        if msg["role"] == "system":
            system = msg["content"]
        else:
            messages.append({
                "role": msg["role"],
                "content": msg["content"]
            })
    
    body = {
        "model": responses_request["model"],
        "messages": messages,
        "stream": True,
        "max_tokens": responses_request.get("max_tokens", 4096),
    }
    
    if system:
        body["system"] = system
    
    return body

import json
from pathlib import Path
 
def add_custom_model(model_config):
    """Add model to Factory settings."""
    settings_path = Path.home() / ".factory" / "settings.json"
    
    if settings_path.exists():
        with open(settings_path) as f:
            settings = json.load(f)
    else:
        settings = {"customModels": []}
    
    settings["customModels"].append(model_config)
    
    with open(settings_path, "w") as f:
        json.dump(settings, f, indent=2)
 
# Example: Add OpenRouter model
add_custom_model({
    "model": "anthropic/claude-3.5-sonnet",
    "provider": "openai",
    "baseUrl": "https://openrouter.ai/api/v1",
    "apiKey": "${OPENROUTER_API_KEY}",
    "displayName": "Claude 3.5 Sonnet (OpenRouter)",
    "maxContextLimit": 200000
})

#!/bin/bash
# setup-codex-shim.sh
 
set -e
 
CODEX_SHIM_DIR="$HOME/Documents/codex-shim"
 
# Clone and install
if [ ! -d "$CODEX_SHIM_DIR" ]; then
    git clone https://github.com/0xSero/codex-shim "$CODEX_SHIM_DIR"
fi
 
cd "$CODEX_SHIM_DIR"
python3 -m pip install --user aiohttp
 
# Symlink commands
mkdir -p "$HOME/.local/bin"
ln -sf "$CODEX_SHIM_DIR/bin/codex-shim" "$HOME/.local/bin/"
ln -sf "$CODEX_SHIM_DIR/bin/codex-app" "$HOME/.local/bin/"
ln -sf "$CODEX_SHIM_DIR/bin/codex-model" "$HOME/.local/bin/"
 
# Generate catalog and start
codex-shim generate
codex-shim start
 
echo "✓ Shim installed and running"
codex-shim status

APP=/Applications/Codex.app
 
# Backup
sudo cp -R "$APP" "$APP.unpatched-$(date +%Y%m%d-%H%M%S)"
 
# Extract ASAR
cd /tmp && rm -rf codex-asar-patch && mkdir codex-asar-patch && cd codex-asar-patch
npx --yes @electron/asar extract "$APP/Contents/Resources/app.asar" extracted
 
# Patch picker filter (disables useHiddenModels check)
PATCH_FILE=$(grep -RIl 'useHiddenModels' extracted/webview/assets/model-queries-*.js | head -n1)
sed -i.bak -E 's/let u=c\.useHiddenModels&&o!==`amazonBedrock`,d;/let u=!1,d;/' "$PATCH_FILE"
 
# Verify exactly one change
diff "$PATCH_FILE.bak" "$PATCH_FILE" && echo "ERROR: No changes made" && exit 1
rm "$PATCH_FILE.bak"
 
# Repack
npx --yes @electron/asar pack extracted app.asar.new
sudo cp app.asar.new "$APP/Contents/Resources/app.asar"
 
# Recompute ASAR header hash for Electron integrity check
HEADER_HASH=$(python3 - "$APP/Contents/Resources/app.asar" <<'PY'
import struct, hashlib, sys
with open(sys.argv[1], 'rb') as f:
    data_size, header_size, _, json_size = struct.unpack('<4I', f.read(16))
    header_json = f.read(json_size)
print(hashlib.sha256(header_json).hexdigest())
PY
)
 
# Update Info.plist
sudo /usr/libexec/PlistBuddy -c \
  "Set :ElectronAsarIntegrity:Resources/app.asar:hash $HEADER_HASH" \
  "$APP/Contents/Info.plist"
 
# Re-sign (ad-hoc)
sudo codesign --force --deep --sign - "$APP"
 
echo "✓ Patch applied. Launch Codex Desktop."

sudo rm -rf "$APP"
sudo mv "$APP.unpatched-YYYYMMDD-HHMMSS" "$APP"

https://chatgpt.com/backend-api/codex/responses
Authorization: Bearer <access_token from auth.json>

# Remove from catalog after generation
jq 'del(.models[] | select(.slug == "openai-gpt-5-5"))' \
  .codex-shim/custom_model_catalog.json > tmp.json && mv tmp.json .codex-shim/custom_model_catalog.json

{
  "customModels": [
    {
      "model": "gpt-5.5",
      "provider": "openai",
      "baseUrl": "https://api.openai.com/v1",
      "apiKey": "${OPENAI_API_KEY}",
      "displayName": "GPT-5.5"
    },
    {
      "model": "claude-opus-4-7-20251109",
      "provider": "anthropic",
      "baseUrl": "https://api.anthropic.com/v1",
      "apiKey": "${ANTHROPIC_API_KEY}",
      "displayName": "Claude Opus 4.7"
    },
    {
      "model": "gemini-2.0-flash-exp",
      "provider": "openai",
      "baseUrl": "https://generativelanguage.googleapis.com/v1beta/openai",
      "apiKey": "${GOOGLE_API_KEY}",
      "displayName": "Gemini 2.0 Flash"
    }
  ]
}

{
  "model": "meta-llama/llama-3.3-70b-instruct",
  "provider": "openai",
  "baseUrl": "https://openrouter.ai/api/v1",
  "apiKey": "${OPENROUTER_API_KEY}",
  "displayName": "Llama 3.3 70B (OpenRouter)"
}

{
  "model": "deepseek-v4-pro",
  "provider": "anthropic",
  "baseUrl": "https://api.deepseek.com/anthropic",
  "apiKey": "${DEEPSEEK_API_KEY}",
  "displayName": "DeepSeek V4 Pro",
  "noImageSupport": true
}

codex-shim status  # Check if running
codex-shim start   # Start if stopped

echo $OPENAI_API_KEY
echo $ANTHROPIC_API_KEY

cat ~/.factory/settings.json | jq '.customModels[].apiKey'

curl https://api.openai.com/v1/models \
  -H "Authorization: Bearer $OPENAI_API_KEY"

cat ~/.codex/auth.json | jq '.auth_mode'
# Should output: "chatgpt"

TOKEN=$(jq -r '.access_token' ~/.codex/auth.json)
curl https://chatgpt.com/backend-api/me \
  -H "Authorization: Bearer $TOKEN"

# Tail daemon logs
tail -f ~/.codex-shim/codex-shim.log
 
# Check last 50 lines
tail -n 50 ~/.codex-shim/codex-shim.log

# Change default port (8765)
codex-shim --port 9876 start
codex-shim --port 9876 app

jq '.customModels[] | select(.model=="deepseek-v4-pro") | .provider' \
  ~/.factory/settings.json

cd ~/Documents/codex-shim
python3 -m pytest tests/ -v

# tests/test_translation.py
import pytest
from codex_shim.translator import translate_to_anthropic
 
@pytest.mark.asyncio
async def test_system_message_extraction():
    request = {
        "model": "claude-opus-4-7",
        "messages": [
            {"role": "system", "content": "You are helpful"},
            {"role": "user", "content": "Hello"}
        ]
    }
    
    result = await translate_to_anthropic(request)
    assert result["system"] == "You are helpful"
    assert len(result["messages"]) == 1