CLAUDE_CODE_MAX_SUBAGENTS_PER_SESSION

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_MAX_SUBAGENTS_PER_SESSION is a Claude Code environment variable: Per-session ceiling on subagent spawns (default 200). When the cap is hit, Claude Code injects a prompt — "Subagent spawn limit reached. Complete the remaining work directly with your tools instead of spawning more agents. Added between v2.1.143 and v2.1.212 and still present in v2.1.294. It is listed in the official reference.

How to set it

For one session, export it in the shell that starts Claude Code:

export CLAUDE_CODE_MAX_SUBAGENTS_PER_SESSION=<value>
claude

To apply it to every session, add it to the env object of a settings file:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CODE_MAX_SUBAGENTS_PER_SESSION": "<value>"
  }
}

Release notes that mention it

• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models
• claude-code-env-vars-v2-1-252
• claude-code-env-vars-v2-1-212

Related variables

• CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS: Ceiling on subagents running at once, default 20; when full Claude Code tells the model to stop and the user to raise this variable.
• CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH: Nesting-depth cap on delegation, default 1 — subagents no longer spawn their own subagents, and the team roster stays flat.
• CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS
• CLAUDE_SUBAGENT_BG_SHELL_MAX_MS: Time cap for shell commands run by background subagents.
• CLAUDE_AGENT: Short-form identifier for the current agent, used in inter-agent messaging and log attribution.
• CLAUDE_AGENT_SDK_CLIENT_APP: Client application name.
• CLAUDE_AGENT_SDK_DISABLE_BUILTIN_AGENTS: Disable built-in agent types.
• CLAUDE_AGENT_SDK_MCP_NO_PREFIX: Don't prefix MCP tool names with server name.

Frequently asked questions

All variables, searchable: Claude Code environment variables.