CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH
A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.217, including the newest one read.
What it is
Number of [subagent layers](/docs/en/sub-agents#let-subagents-spawn-their-own-subagents) allowed below the main conversation (default: 3). At the default, subagents can spawn their own subagents, and a subagent at the third layer can't spawn further; set 1 to turn nesting off. In v2.1.217 through v2.1.218, the default was 1, so a subagent couldn't spawn its own unless you raised the limit; v2.1.219 raised the default to 3. Accepts a positive whole number in plain digits; anything else is ignored, so the limit can be adjusted but not removed. Requires Claude Code v2.1.217 or later
Anthropic's own wording. Read off Environment variables, captured 2026-08-28.
Presence across releases
| Releases | Reading | Declared type | Default |
|---|---|---|---|
| 2.1.245 – 2.1.250 5 releases | never mined | — | — |
| 2.1.217 – 2.1.243 26 releases | in the build | int | — |
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
No changelog entry here has ever named it. That is a statement about what has been written, not about the name: it has been in the build since v2.1.217 without anybody writing a line about it.
Documentation pages
- Environment variables reference table Claude Code CLI
- prompting-claude-opus-5 mentions it Claude Developer Platform
- Subagents in the SDK mentions it Claude Code CLI
- Claude Code changelog mentions it Claude Code CLI
- Create custom subagents 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.
Names beside it
Every environment variable in the inventory starting claude_code_max_subagent, up to twelve of them.
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 environment variable does. All environment variables.