DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.
The SDK now supports a CLAUDE_AGENT_SDK_CLIENT_APP environment variable, allowing client applications built on the SDK to identify themselves in API requests.
Evidence
New client-app identifier support (search for "client-app/", "CLAUDE_AGENT_SDK_CLIENT_APP")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
