Under the hoodTier: how much it should matter to you
3Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
SettingsArea: what it touches
ImprovementsKind: in v2.1.277,
ImprovementsSection of the release
What
The update_settings tool previously only allowed writing to localSettings. It now accepts other recognized setting sources as well, each with its own set of allowed keys.
When the source is userSettings and the key being set is effortLevel, the tool now validates that the value is one of the known, valid effort levels. If it isn't, the call fails with a new dedicated error message that lists the valid effort levels.
Why
This prevents update_settings from silently accepting an invalid effort level and gives a clear, specific error message pointing to the valid options instead of a generic failure.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added sinceA small documentation edit on Configure your agent touched a line naming effortLevel after this was published.* Pass `"userSettings"` to write `effortLevel`, the only key that source accepts. Claude Code saves it as the default effort level for the session's current model, and the running session's effort doesn't change.agent-sdk/configurationsee the edit
Confirmed sinceAnthropic's documentation has since written up effortLevel, on All settings.In an interactive session on your machine, when you save `low`, `medium`, `high`, or `xhigh` as your default with `/effort` or the `/model` picker's effort slider, Claude Code writes that level here under the model you're using, so you rar…settings-referencesee the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up effortLevel, on All settings.
