codex

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Delegate coding tasks to Codex CLI (OpenAI gpt-5-codex via JetBrains AI). Use when a task involves repetitive code generation, refactoring, or analysis that can be offloaded.

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[Developer Tools]

When & Why to Use This Skill

This Claude skill integrates the Codex CLI via JetBrains AI to streamline complex software development workflows. It enables the delegation of intensive coding tasks—such as large-scale refactoring, boilerplate generation, and deep code analysis—to specialized OpenAI models including GPT-4o and o1. By offloading repetitive and mechanical programming chores to a parallel AI processing engine, it significantly boosts developer productivity and allows for more efficient handling of multi-file workspace transformations.

Use Cases

  • Large-scale refactoring: Automatically updating patterns or API usage across dozens of files simultaneously.
  • Automated Test Generation: Creating comprehensive unit tests and boilerplate code for new or existing services (e.g., UserService.kt).
  • Deep Code Analysis: Using high-reasoning models like o1 or o3-mini to identify security vulnerabilities or architectural bottlenecks in complex modules.
  • Codebase Exploration: Quickly mapping REST endpoints, documenting unfamiliar codebases, or performing pattern-based transformations in read-only mode.
  • Parallel Task Execution: Offloading time-consuming documentation or formatting tasks while continuing high-level architectural planning within the main Claude session.
namecodex
descriptionDelegate coding tasks to Codex CLI (OpenAI gpt-5-codex via JetBrains AI). Use when a task involves repetitive code generation, refactoring, or analysis that can be offloaded.

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