CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING is a Claude Code environment variable: Enable fine-grained (eager) input streaming for tools. 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	Network and proxy
Official docs	Listed

How to set it

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

export CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING=<value>
claude

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

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

Release notes that mention it

Claude Code v2.1.80 — Channels, Plugin Simplification, and a Bug Fix Sprint

Related variables

CLAUDE_CODE_MCP_TOOL_IDLE_TIMEOUT
CLAUDE_CODE_STREAMING_TEXT: Likely controlled an experimental streaming text mode that has now graduated to being the default behavior.
CLAUDE_ENABLE_BYTE_WATCHDOG: Activates a byte-level watchdog on API response streams.
CLAUDE_ENABLE_STREAM_WATCHDOG: Enable stream health monitoring.
MCP_TOOL_TIMEOUT: Individual MCP tool execution timeout.
ANTHROPIC_BASE_URL: Custom endpoint for Anthropic services.
API_FORCE_IDLE_TIMEOUT
API_TIMEOUT_MS: Request timeout in milliseconds.

Frequently asked questions

What does CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING do?

Enable fine-grained (eager) input streaming for tools

Which Claude Code version has CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING?

Present since v2.1.69 or earlier and still present in v2.1.294.

How do I set CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING?

Export it before starting Claude Code (export CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING=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.