What probably matters to youSection of the release
What
Ultracode, which runs dynamic workflows (Claude orchestrating extra work) on every task, used to be one of the effort levels, shown as "xhigh + workflows". It is now a separate on/off switch for the session that you combine with any effort level.
The /effort picker has a separate row reading Ultracode: on or off with "select to turn it" on or off and "dynamic workflows on every task". Selecting it sends ultracode on or ultracode off.
/effort usage now reads auto|ultracode [on|off], with a section headed "Ultracode (any effort level, this session only):".
Cycling effort levels left and right no longer includes ultracode, and a current ultracode value is no longer mapped to max or high.
A new session-only ultracode setting is described as "standing dynamic-workflow orchestration at any effort level".
The status label shows the real effort level and adds " · ultracode" when it is on.
The per-model supportsUltra field was dropped.
SDK session state and get_settings report ultracodeRequested and ultracodeAvailable next to ultracode (applied.ultracode). ultracodeAvailable is true when dynamic workflows are enabled and the model supports it; hosts should only offer an Ultracode control while it is true. The ultracode description no longer says it implies xhigh effort.
The check that the live model's effort still matches the recorded level no longer passes the ultracode setting.
Skipping the limit on concurrent subagents (helper agents Claude starts) now only happens when ultracode is on and the model supports it, rather than depending on the effort level. The separate tengu_amber_kestrel bypass is unchanged. The limit itself is still set with CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS.
Why
If you used ultracode before, it now behaves differently: you pick your effort level and turn ultracode on or off on top of it. Sessions at a high effort level without ultracode may now hit the subagent limit where they did not before, and SDK hosts can tell "requested but unavailable" apart from "on".
Read from
Feature flag
tengu_workflows_enabledOn for this account, and not off by default
The flag server returned on for the one account this site reads, and nothing in this release compiles it off by default. The compiled default is shown below, and says which it is when we cannot read one: a fifth of gates compile in a string or a number rather than on or off, and most published releases have no gate table behind them at all. No client can see what the server returns for your account.
This account: on · anonymous baseline: on · compiled default in v2.1.284: on
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
tengu_amber_kestrelNot enough to say
Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.
This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.284: off
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtIt is not settled whether the ultracode row is hidden on plans where workflows are off by default.
Anthropic's release notes agreeAdded effortSlider:decreaseEffort, increaseEffort and toggleUltracode keybinding actions, so the /effort slider's arrow and Tab keys can be…
