{"version":"2.1.315","anchor":"session-init-reports-whether-ultrathink-raises-the-turn-to","canonical_anchor":"session-init-reports-whether-ultrathink-raises-the-turn-to","heading":"Apps and editors can tell whether typing ultrathink raises effort, and settings survive brief read failures","tier":"use","area":"IDE Integration","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.315\/e\/session-init-reports-whether-ultrathink-raises-the-turn-to","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.315","markdown":"### Apps and editors can tell whether typing ultrathink raises effort, and settings survive brief read failures\n\nSDK apps and editor extensions now get ultrathinkAvailable, and a settings file that briefly cannot be read keeps its last known values\n\n**What**\n\nTyping `ultrathink` in a message can make Claude think harder for that turn. Programs that host Claude Code, such as editor extensions and apps built on the Agent SDK, can now find out whether that works:\n\n- The session start message gains an optional `ultrathinkAvailable` field. It is true when typing `ultrathink` runs the turn at xhigh effort, and also when the session is already at xhigh or max, where the turn stays as it is.\n\n- Hosts are told to highlight the word only while the field is true. When it is absent, the host is talking to an older Claude Code.\n\n- The `get_settings` response also gains `ultrathinkAvailable`, and the status report gains `ultrathink_available` when it is known.\n\nSettings loading also changed:\n\n- If a settings file cannot be read but was read successfully before, Claude Code now returns an `unreadable_for_now` result with the last values it read. Before, any unreadable file gave a plain `unreadable` result.\n\n- Certain short-lived read errors no longer throw away the saved copy of the settings.\n\nSmaller additions appear alongside: `sessionBeganAsCopy` in a schema, `ccr_cloud_browser_turn_id` in a list, a `repoHooksListing` entry, voice footer hint counters, and a `substitutionHeredocs` option in the shell parser.\n\n**Why**\n\nEditor extensions and other hosts can highlight `ultrathink` the way the terminal does, and only when it will actually raise effort. A settings file that fails to read for a moment no longer loses your settings for that session.\n\n- Area: IDE Integration\n- Names: `ultrathinkAvailable`\n- Tier: Use it now\n- Useful: 4\/5\n- Signal: 2\/5\n- Scope: individual\n- Heads-up: no"}