---

name: rules description: Use when the user asks about Codex Rules behavior, injected project rules, supported rule file locations, matching, or environment configuration.

Codex Rules

Codex Rules is automatic once the plugin is enabled. It injects:

• static project instructions on SessionStart and UserPromptSubmit
• matching file-specific rules after Codex apply_patch by default

Dynamic PostToolUse output is injected as additional context and is deduplicated per plugin data session. Codex Rules does not rewrite tool output.

Supported project sources:

• CONTEXT.md
• .omo/rules/**/*.md
• .claude/rules/**/*.md
• .cursor/rules/**/*.md
• .github/instructions/**/*.md
• .github/copilot-instructions.md

Supported environment knobs:

• CODEX_RULES_DISABLED=1
• CODEX_RULES_MODE=both|static|dynamic|off
• CODEX_RULES_MAX_RULE_CHARS=<number>
• CODEX_RULES_MAX_RESULT_CHARS=<number>
• CODEX_RULES_ENABLED_SOURCES=CONTEXT.md,.omo/rules

The legacy PI_RULES_* variables are accepted as fallbacks for users migrating from pi-rules.