Codex Skill - JetBrains AI Integration

Use Codex CLI to delegate coding tasks that benefit from parallel AI processing.

When to Use Codex

GOOD for Codex:

• Large-scale refactoring across many files
• Repetitive code generation (boilerplate, tests)
• Code analysis and documentation
• Pattern-based transformations
• Exploring unfamiliar codebases

KEEP in Claude:

• Complex architectural decisions
• Security-sensitive code
• Tasks requiring deep context understanding
• Interactive problem-solving with user

Configuration

Codex is pre-configured with JetBrains AI staging:

• Provider: jbai-staging
• Models: gpt-4o-2024-11-20, o1-2024-12-17, o3-mini-2025-01-31

Usage Patterns

Quick Analysis (read-only)

codex exec -c model_provider=jbai-staging --model "gpt-4o-2024-11-20" \
  --sandbox read-only \
  "Analyze the codebase and list all REST endpoints" 2>/dev/null

Code Generation (workspace-write)

codex exec -c model_provider=jbai-staging --model "gpt-4o-2024-11-20" \
  --sandbox workspace-write --full-auto \
  "Generate unit tests for UserService.kt" 2>/dev/null

Heavy Reasoning (o1/o3 models)

codex exec -c model_provider=jbai-staging --model "o3-mini-2025-01-31" \
  --sandbox read-only \
  "Review security vulnerabilities in auth module" 2>/dev/null

Resume Previous Session

echo "continue with the refactoring" | codex exec --skip-git-repo-check resume --last 2>/dev/null

Decision Framework

Before delegating to Codex, consider:

Factor	Use Codex	Keep in Claude
File count	Many files	Few files
Task type	Repetitive/mechanical	Creative/strategic
Context needed	Self-contained	Requires conversation context
User interaction	None needed	Back-and-forth required

Execution Protocol

1. Announce intent: Tell user you're delegating to Codex and why
2. Choose model:
   • gpt-4o-2024-11-20 for fast tasks
   • o1-2024-12-17 / o3-mini-2025-01-31 for complex reasoning
3. Choose sandbox:
   • read-only for analysis
   • workspace-write for edits
4. Run command with 2>/dev/null to suppress thinking tokens
5. Report results back to user
6. Offer resume: "Say 'codex resume' to continue this session"

Safety Rules

• Always use --skip-git-repo-check flag
• Default to read-only sandbox unless edits needed
• Never use danger-full-access without explicit user permission
• Suppress stderr with 2>/dev/null by default