CLAUDE_CODE_DISABLE_STRUCTURED_OUTPUTS

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_DISABLE_STRUCTURED_OUTPUTS is a Claude Code environment variable: Turns structured outputs off for gateways or providers (such as Mantle) that reject them. The changelog ties this to session titles, memory recall and prompt hooks failing in that setup; with the variable set, Claude Code skips the structured-outputs path those features use. Added in v2.1.288. Added in v2.1.288 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_DISABLE_STRUCTURED_OUTPUTS=<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_STRUCTURED_OUTPUTS": "<value>"
  }
}

Release notes that mention it

• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models
• claude-code-env-vars-v2-1-288

Related variables

• CLAUDE_CODE_DISABLE_ADMIN_ENV_UNION
• CLAUDE_CODE_DISABLE_ARTIFACT
• CLAUDE_CODE_DISABLE_ATTACHMENTS: File/image attachments.
• 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_EXPERIMENTAL_BETAS: Experimental beta API features.
• CLAUDE_CODE_DISABLE_EXPLORE_INHERIT_CAP: Lets the built-in Explore search agent run at the parent model instead of a cheaper capped default.

Frequently asked questions

All variables, searchable: Claude Code environment variables.