AI Providers

Katachi supports multiple AI providers. Each provider can be configured via OAuth or API keys.

Supported Providers

Claude (Anthropic)

Uses the Claude Agent SDK with native tool use and orchestration.

Model	Description
claude-opus-4-6	Most capable (Feb 2026)
claude-sonnet-4-6	Balanced performance
claude-opus-4-5	Previous flagship
claude-sonnet-4-5	Previous balanced
claude-haiku-4-5	Fast and lightweight

Auth: OAuth (claude login) or API key

Gemini (Google)

Uses the Gemini CLI Core SDK.

Model	Description
gemini-3.1-pro-preview	Latest flagship
gemini-3-flash-preview	Latest fast

Auth: OAuth (gemini login) or API key

OpenAI / Codex

Uses the OpenAI API (API key path) or the Codex SDK (OAuth path). OAuth authenticates via ~/.codex/auth.json and routes through the ChatGPT backend.

Model	Description
gpt-5.4	Latest flagship (Mar 2026)
gpt-5.3-codex	Purpose-built for SE agents

Auth: OAuth (codex login) or API key

Copilot (GitHub)

Uses the Copilot SDK. Agent-mode models only — chat-only models are excluded.

Model	Description
copilot-gpt-5.4	GPT latest flagship
copilot-gpt-5.3-codex	GPT codex (SE-focused)
copilot-claude-opus-4.6	Claude most capable
copilot-claude-opus-4.6-fast	Claude capable fast
copilot-claude-sonnet-4.6	Claude balanced ★ Default
copilot-gemini-3.1-pro	Gemini flagship
copilot-gemini-3-flash	Gemini fast
copilot-grok-code-fast-1	xAI Grok (code-focused)

Auth: OAuth (run /login in Copilot CLI)

API Profiles (Custom Providers)

Katachi supports third-party and custom providers via API Profiles in the web UI. Any OpenAI-compatible API can be added with an API key and base URL.

Provider	Status
Z.ai	Supported
OpenRouter	Experimental
Custom OpenAI-compatible API	Supported

Auth: API key (configured in Settings → API Profiles)

Authentication

OAuth (Recommended)

OAuth lets you use your existing provider accounts without managing API keys.

Claude

claude login

Gemini

gemini login

Codex

codex login

Copilot

Run /login from within the GitHub Copilot CLI to authenticate.

The agent automatically detects OAuth tokens from the provider CLIs.

API Keys

You can set API keys via the Web UI:

1. Open katachi.live
2. Go to Settings → API Profiles
3. Add your API key for the desired provider

Keys are stored securely in your OS keychain (via keytar), encrypted with a machine-specific key.

Priority Order

When multiple auth methods are available, the agent uses this priority:

1. API Profile (from web UI) — highest priority
2. OAuth Token — default fallback

Selecting a Provider

In the web UI, select your provider and model when creating a new session. You can switch providers between sessions — each session remembers its configuration.