CLAUDE_CODE_FILE_READ_MAX_PDF_PAGES_PER_MESSAGE

Updated October 14, 2026 by Alex Sorokoletov

CLAUDE_CODE_FILE_READ_MAX_PDF_PAGES_PER_MESSAGE is a Claude Code environment variable: Caps how many PDF pages the Read tool loads within a single message. A value below the built-in limit trims the pages pulled in per message. Added in v2.1.300 and still present in v2.1.300. It is not in the official reference.

How to set it

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

export CLAUDE_CODE_FILE_READ_MAX_PDF_PAGES_PER_MESSAGE=<value>
claude

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

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

Release notes that mention it

• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models
• claude-code-env-vars-v2-1-300

Related variables

• CLAUDE_CODE_FILE_READ_MAX_PDF_PAGES_PER_TURN: Caps the running total of PDF pages the Read tool loads across a turn, working with the per-message cap above.
• CLAUDE_CLIENT_PRESENCE_FILE
• CLAUDE_CODE_DIAGNOSTICS_FILE: Path to write diagnostics output.
• CLAUDE_CODE_MAX_TURNS: Hard cap on conversation turns.
• CLAUDE_CODE_USE_NATIVE_FILE_SEARCH
• CLAUDE_ENV_FILE: Path to environment file for session variables.
• TASK_MAX_OUTPUT_LENGTH: Max output length for Task tool results.
• CLAUDE_AI_PROJECTS_READ_SCOPE

Frequently asked questions

All variables, searchable: Claude Code environment variables.