CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY
Updated by Alex Sorokoletov
CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY is a Claude Code environment variable: Max concurrent tool executions; default 10. Present since v2.1.69 or earlier and still present in v2.1.294. It is listed in the official reference.
| Status | Present in v2.1.294 |
|---|---|
| Added | Present since v2.1.69 or earlier |
| Category | Shell and tools |
| Official docs | Listed |
How to set it
For one session, export it in the shell that starts Claude Code:
export CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY=<value>
claudeTo apply it to every session, add it to the env object of a settings file:
// ~/.claude/settings.json
{
"env": {
"CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY": "<value>"
}
}Release notes that mention it
Related variables
CLAUDE_CODE_EMIT_TOOL_USE_SUMMARIES: Emit tool use summary events.CLAUDE_CODE_USE_POWERSHELL_TOOL: Enables a PowerShell-specific tool variant for Windows environments.CLAUDE_CODE_TOOL_USE_IDCLAUDE_SDK_CAN_USE_TOOL_SHADOWEDBASH_MAX_OUTPUT_LENGTH: Max bash output character length.CLAUDE_CODE_DISABLE_ADVISOR_TOOL: Disables what appears to be an internal advisory tool.CLAUDE_CODE_ENABLE_EXPERIMENTAL_ADVISOR_TOOL: Enables the experimental Advisor Tool — a server-side tool with its own advisorModel config option.CLAUDE_CODE_MAX_WEB_SEARCHES_PER_SESSION: Per-session ceiling on WebSearch tool calls (default 200), gated by a web_search_session_cap.
Frequently asked questions
What does CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY do?
Max concurrent tool executions; default 10
Which Claude Code version has CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY?
Present since v2.1.69 or earlier and still present in v2.1.294.
How do I set CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY?
Export it before starting Claude Code (export CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY=value), or add it to the "env" object in ~/.claude/settings.json to apply it to every session.
All variables, searchable: Claude Code environment variables.