omo-claude-auth

An omo extension that lets omo use your existing Claude Code login. It wraps opencode-claude-auth and leaves the plugin's code unchanged.

How it works

opencode-claude-auth does all of its work inside the fetch function that its OpenCode auth loader returns: reading credentials from the macOS Keychain or ~/.claude/.credentials.json, refreshing OAuth tokens, adding Claude Code headers and beta flags, renaming tools, transforming the response stream, and retrying requests.

This extension:

1. Runs the plugin with a stub OpenCode context to get that fetch.
2. Starts a loopback HTTP proxy on 127.0.0.1 that sends every request through it.
3. Adds the Claude Code system identity to each request, which the plugin's experimental.chat.system.transform hook does in OpenCode.
4. Registers a claude-code provider that uses omo's built-in anthropic-messages API, with the proxy as its baseUrl.

To get plugin fixes, run bun update opencode-claude-auth.

Requirements

• Claude Code installed and logged in (run claude at least once)
• omo (senpi)
• Bun

Installation

Add the npm package to packages in your omo settings (~/.omo/agent/settings.json):

{
  "packages": ["npm:omo-claude-auth"]
}

Or install from source:

git clone https://github.com/devxoul/omo-claude-auth.git
cd omo-claude-auth
bun install

Then add the folder to packages. Relative paths resolve from the agent directory:

{
  "packages": ["/path/to/omo-claude-auth"]
}

To try it without changing settings, run omo -e /path/to/omo-claude-auth/index.ts.

Usage

Select one of the claude-code/* models:

omo --list-models claude-code
omo --model claude-code/claude-opus-5-5

Model	Context	Max output
claude-code/claude-opus-5-5	200K	64K
claude-code/claude-sonnet-5-5	200K	64K
claude-code/claude-haiku-5-5	200K	64K
claude-code/claude-opus-5	200K	64K

The context window is capped at 200K because longer context can be billed as extra usage. To change the model list, edit MODELS in index.ts.

If no Claude Code OAuth credentials are found, the extension logs a warning and doesn't register the provider.

The plugin's environment variables (ANTHROPIC_CLI_VERSION, ANTHROPIC_BETA_FLAGS, CLAUDE_AUTH_DEBUG, CLAUDE_CONFIG_DIR, and others) still apply. See the opencode-claude-auth README.

Side effects

These come from opencode-claude-auth:

• It writes tokens to OpenCode's auth.json at startup and every 5 minutes.
• When it refreshes a token, it writes the new token back to the Keychain entry or credentials file. Claude Code uses the same entry, so a refresh also rotates Claude Code's token.

Disclaimer

This project is not affiliated with or endorsed by Anthropic.

It uses Claude Code's OAuth credentials to authenticate with Anthropic's API. Anthropic's Terms of Service say that Claude Pro/Max subscription tokens should only be used with official Anthropic clients. Using this extension may violate those terms and could put your account at risk. It may also stop working whenever Anthropic changes its OAuth flow, headers, or billing checks. Use it at your own risk.

If you want subscription usage through an official path, omo's built-in anthropic-subscription provider routes requests through the Claude Agent SDK instead.

License

MIT

This project depends on opencode-claude-auth, which is MIT-licensed by its authors.