effortLevel
A Claude Code settings key, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.
What it is
Save the [/effort level](/docs/en/model-config#adjust-effort-level) so future sessions reason more or less deeply
Anthropic's own wording. Read off Claude Code settings reference, captured 2026-08-28.
Presence across releases
| Releases | Reading | Declared type | Default |
|---|---|---|---|
| 2.1.245 – 2.1.250 5 releases | never mined | — | — |
| 2.1.138 – 2.1.243 95 releases | in the build | — | — |
A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.
Changelog entries naming it
-
v2.1.239New
modelSettingsconfig key holds per-model effortA new modelSettings config key stores an effort level per model, from low to xhigh.
named in this entry
-
v2.1.239Per-model effort level in settings, behind a gate
You could set an effort level per model in settings, but the lookup is gated off.
named in this entry
Documentation pages
- Claude Code settings reference reference table Claude Code CLI
- Claude Code settings reference table Claude Code CLI
- Agents mentions it Claude Developer Platform
- Create Agent mentions it Claude Developer Platform
- Update Agent mentions it Claude Developer Platform
- Sessions mentions it Claude Developer Platform
- Create Session mentions it Claude Developer Platform
- apple-foundation-models mentions it Claude Developer Platform
- Agent SDK reference - Python mentions it Claude Code CLI
- Agent SDK reference - TypeScript mentions it Claude Code CLI
- Manage multiple agents with agent view mentions it Claude Code CLI
- Claude Code changelog mentions it Claude Code CLI
- CLI reference mentions it Claude Code CLI
- Environment variables mentions it Claude Code CLI
A reference table page is one whose own table defines this name, and it is where the description above came from. A page that mentions it carries the name somewhere in its text and may say nothing about it at all. Every page carrying it.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the settings key does. All settings keys.