The SDK query client gains an updateSettings(source, settings) method, which sends a new update_settings control-protocol subtype and is tracked under a dedicated telemetry span.
Names in the bundleupdateSettings
Documented inclaude-code/agent-sdk/typescript
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 since
A small documentation edit on Configure your agent touched a line naming updateSettings after this was published.
* **`updateSettings()`**: writes one allowlisted key to a settings file. The [`updateSettings()` reference](/docs/en/agent-sdk/typescript#updatesettings) names the key each source accepts and the version floors.agent-sdk/configuration see the edit
Confirmed since
Anthropic's documentation has since written up updateSettings, on Agent SDK reference - TypeScript.
| `updateSettings(source, settings)` | Merges settings into the project's local settings file, `.claude/settings.local.json`; they take effect on the next request. Accepts only `source: 'localSettings'` and an allowlisted key set, currentl…agent-sdk/typescript see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up updateSettings, on Agent SDK reference - TypeScript.