CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD

Updated November 3, 2026 by Alex Sorokoletov

CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD is a Claude Code environment variable: Set to skip transcript read-ahead; when unset, an SDK-URL session reads the transcript ahead and can abort before continuing. Added in v2.1.318 and still present in v2.1.318. It is not in the official reference.

Status	Present in v2.1.318
Added	Added in v2.1.318
Category	Feature toggles
Official docs	Not listed

How to set it

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

export CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD=<value>
claude

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

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

Related variables

CLAUDE_CODE_DISABLE_ADMIN_ENV_UNION: When set to true, uses only the leading admin tier's environment settings instead of merging (unioning) the environment across all admin tiers.
CLAUDE_CODE_DISABLE_ARTIFACT
CLAUDE_CODE_DISABLE_ATTACHMENTS: File/image attachments.
CLAUDE_CODE_DISABLE_AWAITING_USER_IDLE: When set, stops the session from being treated as idle while it waits for user input, so time parked on the user is not counted as idle.
CLAUDE_CODE_DISABLE_CFC_PROMPT
CLAUDE_CODE_DISABLE_COMMAND_INJECTION_CHECK: Previously allowed disabling command injection detection.
CLAUDE_CODE_DISABLE_CRON: Disable cron/scheduled task functionality.
CLAUDE_CODE_DISABLE_DIR_SYNC: Turns off the background directory-sync worker on a remote session.

Frequently asked questions

What does CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD do?

Set to skip transcript read-ahead; when unset, an SDK-URL session reads the transcript ahead and can abort before continuing.

Which Claude Code version has CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD?

Added in v2.1.318 and still present in v2.1.318.

How do I set CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD?

Export it before starting Claude Code (export CLAUDE_CODE_DISABLE_TRANSCRIPT_READ_AHEAD=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.