[DOCS] Agent SDK authentication restriction should be more prominent than a Note box in step 2

Documentation Type

Unclear/confusing documentation

Documentation Location

https://platform.claude.com/docs/en/agent-sdk/overview

Section/Topic

Agent SDK overview > "Get started" > Step 2 "Set your API key"

Current Documentation

The authentication restriction is in a <Note> box inside step 2 of "Get started":

Unless previously approved, Anthropic does not allow third party developers to offer claude.ai login or rate limits for their products, including agents built on the Claude Agent SDK. Please use the API key authentication methods described in this document instead.

What's Wrong or Missing?

This is an important policy statement that affects whether developers can ship products, but it's buried in a collapsible step inside the quickstart flow. A developer who skims the overview to understand what the SDK offers may not read step 2 of the setup instructions.

Additionally, the restriction is framed only in terms of the Agent SDK. Third-party projects that wrap the Claude Code CLI binary (rather than using the SDK) may not realize this policy applies to them, since they don't read the Agent SDK docs at all.

The branding guidelines section at the bottom of the same page is a more natural location for policy restrictions, but it only covers naming/visual branding, not authentication method restrictions.

Suggested Improvement

1. Move or duplicate the authentication restriction to the "Branding guidelines" section (renamed to "Branding and usage guidelines") where developers looking for policy information would naturally find it.

1. Broaden the language to cover all third-party products using Claude Code, not just Agent SDK-based ones:

Anthropic does not allow third-party developers to offer claude.ai login or rate limits for their products. This applies to products built with the Agent SDK, products wrapping the Claude Code CLI, and any other integration. Please use API key authentication.

1. Consider adding a <Warning> callout at the top of the overview page (before the code examples) for this policy, since it's a hard constraint that affects architectural decisions.

Impact

Medium - Makes feature difficult to understand

Additional Context

The Vibe Companion project's README prominently advertises "No API key needed -- uses your existing Claude Code subscription" as a feature. This suggests the authentication restriction in the Agent SDK docs is either not being seen by developers or not being understood as applying to CLI-wrapping projects. Making the restriction more prominent and broadly scoped would help.