[FEATURE] Allow Max/Pro subscription authentication for third-party IDE integrations

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

As a Pro/Max subscriber, I can use Claude Code CLI authenticated with my subscription. However, when I want to use the native Claude integration in JetBrains IDEs (announced here: https://blog.jetbrains.com/ai/2025/09/introducing-claude-agent-in-jetbrains-ides/), I'm required to pay separately for API access.

This creates an inconsistent experience:

• Claude Code (developer tool) → Pro/Max subscription works
• JetBrains integration (developer tool) → Max subscription doesn't work

Both are developer tools, but only Anthropic's own CLI supports subscription-based authentication.

Proposed Solution

1. Allow claude setup-token to generate an API-compatible key (sk-ant-api03- format) that works with third-party integrations
2. Work with JetBrains to accept OAuth tokens (sk-ant-oat01- format) in their integration
3. Expose a subscription-linked API key in console.anthropic.com for Max/Pro users (with usage limits matching the subscription tier)

Alternative Solutions

I attempted to use claude setup-token to generate a long-lived authentication token from my Max subscription. The command successfully generated a token in the format sk-ant-oat01-... (OAuth Access Token).

However, the JetBrains integration does not accept this token — I guess it expects a standard API key format (sk-ant-api03-...) from console.anthropic.com. The OAuth token is incompatible.

This means Anthropic already has the infrastructure to generate tokens from subscriptions, but third-party integrations can't use them due to format incompatibility.

Priority

Medium - Would be very helpful

Feature Category

API and model interactions

Use Case Example

_No response_

Additional Context

Pro/Max Subscribers who prefer native IDE integration over CLI are forced to pay twice for essentially the same capability. The setup-token command shows the infrastructure exists — it's just a matter of compatibility.