lex-llm-openai

LegionIO LLM provider extension for OpenAI.

This gem lives under Legion::Extensions::Llm::Openai and depends on lex-llm for shared provider-neutral routing, fleet, and schema primitives.

Load it with require 'legion/extensions/llm/openai'.

What It Provides

• Legion::Extensions::Llm::Provider registration as :openai
• Chat completions via POST /v1/chat/completions
• Streaming chat completions (same endpoint, stream: true)
• Model discovery via GET /v1/models
• Model retrieval via GET /v1/models/{model}
• Embeddings via POST /v1/embeddings
• Moderation via POST /v1/moderations
• Image generation via POST /v1/images/generations
• Image editing via POST /v1/images/edits
• Image variation via POST /v1/images/variations
• Audio transcription via POST /v1/audio/transcriptions
• Streaming token usage reporting (stream_usage_supported?)
• Shared OpenAI-compatible request/response mapping via Legion::Extensions::Llm::Provider::OpenAICompatible
• Normalized chat, embedding, moderation, image, and audio capability mapping for discovered models
• Shared fleet/default settings via Legion::Extensions::Llm.provider_settings
• Best-effort llm.registry availability event publishing for discovered models

Architecture

Legion::Extensions::Llm::Openai
├── Provider                              # OpenAI provider implementation (chat, models, embeddings, etc.)
│   └── Capabilities                      # Model family capability predicates
├── RegistryPublisher                     # Async llm.registry event publisher
├── RegistryEventBuilder                  # Sanitized registry event envelope builder
└── Transport
    ├── Exchanges::LlmRegistry            # Topic exchange for llm.registry
    └── Messages::RegistryEvent           # AMQP message for registry events

Observability

All classes include Legion::Logging::Helper (when available) providing:

• Structured handle_exception calls on every rescue block
• Info-level action logging for provider registration, model listing, model retrieval, and registry publishing
• Automatic log segment derivation and component type tagging

Defaults

Legion::Extensions::Llm::Openai.default_settings
# {
#   provider_family: :openai,
#   instances: {
#     default: {
#       endpoint: "https://api.openai.com",
#       tier: :frontier,
#       transport: :http,
#       credentials: { api_key: "env://OPENAI_API_KEY" },
#       usage: { inference: true, embedding: true, moderation: true, image: true, audio: true },
#       limits: { concurrency: 4 }
#     }
#   }
# }

Configuration

Legion::Extensions::Llm.configure do |config|
  config.openai_api_key = ENV.fetch("OPENAI_API_KEY")
  config.openai_api_base = nil                          # defaults to https://api.openai.com
  config.openai_organization_id = nil                   # optional OpenAI-Organization header
  config.openai_project_id = nil                        # optional OpenAI-Project header
  config.default_model = "gpt-5.2"
  config.default_embedding_model = "text-embedding-3-small"
  config.default_moderation_model = "omni-moderation-latest"
  config.default_image_model = "gpt-image-1"
  config.default_transcription_model = "gpt-4o-transcribe"
end

Dependencies

Gem	Purpose
lex-llm (>= 0.1.5)	Shared provider contract, fleet settings, routing
legion-json (>= 1.2.1)	JSON serialization
legion-logging (>= 1.3.2)	Structured logging via Helper
legion-settings (>= 1.3.14)	Configuration management

Development

bundle install
bundle exec rspec --format progress   # all pass
bundle exec rubocop -A                # auto-fix
bundle exec rubocop                   # lint check (0 offenses)

License

MIT