The update_settings tool now accepts more setting sources, including a validated effortLevel under userSettings
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.
* 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/configuration see the edit
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-reference see the edit
Anthropic's documentation has since written up effortLevel, on All settings.