anthropic_api_key insufficient - misleading 'Credit balance is too low' error when Claude Code subscription required

[danhumphrey]

Summary

Setting up claude-code-action@v1 with a valid anthropic_api_key (fresh key, $30 USD balance on platform.claude.com) consistently fails with:

Claude Code returned an error result: Credit balance is too low

The error is misleading — the real issue is that the action requires a Claude Code subscription or OAuth token, not just API credits.

Steps to reproduce

1. Create an API key on platform.claude.com with credits
2. Add as ANTHROPIC_API_KEY GitHub secret
3. Configure workflow with only anthropic_api_key input (as documented)
4. Trigger PR review

Expected behaviour

Either works correctly, or fails with a clear error explaining that a Claude Code subscription/OAuth token is required.

Actual behaviour

Fails instantly (duration_ms: 180, total_cost_usd: 0) with Credit balance is too low — no indication that the credential type is wrong.

Root cause (inferred)

The action uses @anthropic-ai/claude-agent-sdk which internally runs the claude CLI. That CLI checks for a Claude Code subscription, not just API access. A raw anthropic_api_key from platform.claude.com is not sufficient without a linked Claude Code subscription.

Additional pain points

1. README implies anthropic_api_key is sufficient — it is not, at least not without a Claude Code subscription
2. console.anthropic.com redirects to platform.claude.com with no indication this is a separate billing system from claude.ai subscriptions — developers with a Max plan have no reason to know a second account with separate credits is needed
3. claude_code_oauth_token is not clearly documented as the likely correct credential for most users
4. The billing separation between claude.ai and platform.claude.com is not mentioned anywhere in the action docs

Environment

• anthropics/claude-code-action@v1
• GitHub Actions, ubuntu-latest
• Auth method: anthropic_api_key only
• No claude_code_oauth_token provided

[danhumphrey]

Claude was unable to setup claude in my pipeline. we reverted to copilot only.

[swofford]

I'm suddenly having the same problem, but I'm confused. Is it possible to get the Claude Agent to run in a Jetbrains IDE if you an an account with Anthropic?