claude-code-auth

A core-auth provider that signs in to Claude with the real Claude Code OAuth flow and lets you add multiple Claude subscription accounts. Both Claude Code (via the loader proxy) and OpenCode route requests through it, rotating accounts and respecting each one's subscription rate limits — so OpenCode uses your Claude Code subscription instead of a pay-per-token API key.

Under-the-Hood Architecture

flowchart TD
    subgraph Driver [claude-code driver — thin layer on core-auth]
        HANDLE["handle(request) — Anthropic request rewrite"]
        LOGIN["loginFlow() — PKCE OAuth"]
    end
    subgraph Core [core-auth]
        MGR[AccountManager: select / refresh / rotate]
        STORE[(accounts.json)]
        MGR <--> STORE
    end
    CC[Claude Code loader proxy] -->|dist/handler.js handle| HANDLE
    OC[OpenCode loader] -->|loader.fetch| HANDLE
    HANDLE -->|acquire account + token| MGR
    HANDLE -->|"Bearer + anthropic-beta: oauth + Claude Code system block"| API[(api.anthropic.com)]
    API -->|429 / 529| MGR
    LOGIN -->|platform.claude.com OAuth| STORE

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Structure

• src/ — TypeScript source (driver/ driver + OAuth config/login, oauth/ PKCE flow, plugin/request.ts Anthropic rewrite, commands.ts slash-commands, handler.ts/index.ts/cli.ts entries)
• core-auth/ — the shared auth engine (git submodule)
• core/ — shared intisy-ai/core submodule (config + logging + command framework), bundled in
• dist/ — Compiled bundles: index.js (OpenCode), handler.js (Claude loader), cli.js (CLI)

Installation

Via plugin-updater (recommended)

Add to ~/.config/opencode/config/plugins.json:

[{ "name": "claude-code-auth", "url": "https://github.com/intisy-ai/claude-code-auth", "enabled": true }]

Via npm

npm install claude-code-auth

Add Claude accounts (shared by both apps):

npx claude-code-auth login    # repeat to add more accounts
npx claude-code-auth list

Configuration

Config files are never auto-created on launch — settings are registered with defaults (core defineConfig) and edited in the loader's Plugins → Configure screen (or /<plugin>-config); a file is written only when you change a value. Global console logging for every plugin is toggled in config/settings.json (logConsole: true, the opencode.json-equivalent).

Accounts are stored by core-auth at ~/.config/opencode/accounts.json (and ~/.claude/... for Claude Code). The OAuth client is the public Claude Code installed-app client; override the client id with CLAUDE_CODE_CLIENT_ID if needed.

• OpenCode: registers a custom claude-code provider (SDK @ai-sdk/anthropic); run opencode run -m claude-code/claude-sonnet-4-6.
• Claude Code: select claude-code in the loader's Providers tab; the proxy routes Claude requests through your subscription accounts.

Plugin config (claude-code-auth.json) is editable from chat via /claude-code-auth-config.

Commands

Deployed automatically to both apps on load (~/.config/opencode/command/ and ~/.claude/commands/):

Command	Description
/claude-code-auth-config	View/change any config key: list, get <key>, set <key> <value>. 100% of the config is reachable here.
/claude-accounts	List signed-in Claude subscription accounts and their enabled state.

Dependencies

• core (required) — bundled git submodule (config + logging + commands); no separate install.
• core-auth (required) — bundled git submodule (account store + OAuth/rotation engine).
• sync-bridge (optional) — mirrors the account store to the other app when present.

Logging

core-auth writes provider logs under the app config dir (~/.config/opencode/logs/... or ~/.claude/logs/...).

License

MIT