op-anthropic-auth

OpenCode plugin for Anthropic Oauth, no extra usage required.

Use Claude Pro/Max with browser OAuth, create an Anthropic API key through OAuth, or enter an API key manually.

Features

• Claude Pro/Max login from /connect
• Automatic token refresh
• Claude-compatible request shaping for OpenCode
• Extra model registration through config

[!WARNING] Use at your own risk. This may go against Anthropic TOS.

[!NOTE] Anthropic auth changes are closely monitored for quick compatibility updates.

Quick start

Add the plugin to ~/.config/opencode/opencode.json:

{
  "plugin": ["op-anthropic-auth@latest"]
}

Restart OpenCode, run /connect, then choose one of:

• Claude Pro/Max
• Create an API Key
• Manually enter API Key

Manual install

If your client does not auto-install npm plugins from config:

npm i -g op-anthropic-auth@latest

Then use the same config:

{
  "plugin": ["op-anthropic-auth"]
}

Extra models

{
  "plugin": [
    [
      "op-anthropic-auth",
      {
        "extraModels": {
          "claude-new-model": {
            "name": "Claude New Model"
          }
        }
      }
    ]
  ]
}

claude-opus-4.7 is included by default.

Verify

npm run smoke

How it works

The plugin:

• runs a PKCE OAuth flow against Claude or Anthropic
• stores refreshable auth in the OpenCode auth store
• refreshes tokens when needed
• adds the required Anthropic beta headers
• rewrites system and tool metadata for Claude-compatible requests

Troubleshooting

• Re-run /connect if auth looks stale
• Clear the cached package if a new version is not loading:

rm -rf ~/.cache/opencode/packages/op-anthropic-auth@latest/

If something breaks, please open an issue with your OpenCode version, plugin version, and error output

License

MIT