{"version":"2.1.271","anchor":"fast-mode-session-promotion-tied-to-a-first-partysession-to","canonical_anchor":"fast-mode-penguin-mode-gains-a-per-session-opt-in-path-a","heading":"Fast mode gains a per-session opt-in check","tier":"notice","area":"Models","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.271\/e\/fast-mode-session-promotion-tied-to-a-first-partysession-to","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.271","markdown":"### Fast mode gains a per-session opt-in check\n\nFast (\"penguin\") mode now checks a per-session opt-in before enabling, instead of only an org-wide check\n\n**Unclear.** placeholder\n\n**What**\n\nFast mode (also called \"penguin mode\") now factors a `sessionOptIn` value into its eligibility logic instead of relying only on a bare unavailability check.\n\n- The fast-mode-unavailable check now only blocks the request when the user is actually trying to turn fast mode on, not when merely checking status or disabling it.\n\n- A new policy-settings-driven rejection path checks whether fast mode is disallowed by policy and whether it's restricted to per-session opt-in (`fastModePerSessionOptIn`).\n\n- A new environment variable, `CLAUDE_CODE_SKIP_FAST_MODE_ORG_CHECK`, can skip the organization-level check, and this is recorded via a `reason: \"preference\"` marker.\n\n- A new `tengu_org_penguin_mode_fetch_refused` telemetry event fires when the org status endpoint refuses the request with a specific permission error.\n\n- Enabling fast mode now runs an extra promotion step after swapping the main-loop model, when the session-opt-in condition is met.\n\n**Why**\n\nThis lets fast mode be gated per session rather than only by a blanket organization setting, so it can be turned on or off more precisely without the request being wrongly blocked when it's only a status check.\n\n- Area: Models\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 3\/5"}