The default macOS Claude Code install stores OAuth under the Keychain
generic-password service "Claude Code-credentials" and never writes
~/.claude/.credentials.json, so available()'s file-or-env sniff reported
"No Claude auth found" while claude -p worked fine. On darwin the sniff
now also probes the Keychain entry — metadata only (no -w, the secret is
never read), 5s timeout, any security(1) failure degrades to not-found.
Verified live on this machine (subscription install, no creds file,
Keychain entry present).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>