{"version":"2.1.269","anchor":"new-oauth-bearer-attribution-probe-lataat-sends-a-backgro","canonical_anchor":"new-oauth-bearer-attribution-probe-lataat-sends-a-backgro","heading":"New OAuth bearer attribution probe (lat\/aat) sends a background token-validation ping","tier":"internal","area":"Auth","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.269\/e\/new-oauth-bearer-attribution-probe-lataat-sends-a-backgro","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.269","markdown":"### New OAuth bearer attribution probe (lat\/aat) sends a background token-validation ping\n\nA background check now validates and times the OAuth login token for first-party sessions\n\n**What**\n\nClaude Code now runs a background check that validates the current OAuth bearer token (the credential sent with requests to prove who is logged in) and measures how long that check takes. It only runs this for first-party sessions (i.e. logged in directly with Claude, not through another integration), logs a warning if the check fails, and records the timing and outcome. A related helper classifies how the session is authenticated into categories such as `claude_ai_oauth`, `oauth_token_env`, `auth_token_env`, `api_key_helper`, or `wif`.\n\n**Why**\n\nThis gives Anthropic visibility into authentication health and latency without affecting normal usage, helping diagnose login or token problems by authentication method.\n\n- Area: Auth\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 3\/5"}