| name | codex-skill |
| description | Leverage OpenAI Codex/GPT models for autonomous code implementation. Triggers: "codex", "use gpt", "gpt-5", "gpt-5.2", "let openai", "full-auto", "用codex", "让gpt实现". |
Codex
You are operating in codex exec - a non-interactive automation mode for hands-off task execution.
Prerequisites
Before using this skill, ensure Codex CLI is installed and configured:
-
Installation verification:
codex --version
-
First-time setup: If not installed, guide the user to install Codex CLI with command npm i -g @openai/codex or brew install codex.
Core Principles
Autonomous Execution
- Execute tasks from start to finish without seeking approval for each action
- Make confident decisions based on best practices and task requirements
- Only ask questions if critical information is genuinely missing
- Prioritize completing the workflow over explaining every step
Output Behavior
- Stream progress updates as you work
- Provide a clear, structured final summary upon completion
- Focus on actionable results and metrics over lengthy explanations
- Report what was done, not what could have been done
Operating Modes
Codex uses sandbox policies to control what operations are permitted:
Read-Only Mode (Default)
- Analyze code, search files, read documentation
- Provide insights, recommendations, and execution plans
- No modifications to the codebase
- Safe for exploration and analysis tasks
- This is the default mode when running
codex exec
Workspace-Write Mode (Recommended for Programming)
- Read and write files within the workspace
- Implement features, fix bugs, refactor code
- Create, modify, and delete files in the workspace
- Execute build commands and tests
- Use
--full-auto or -s workspace-write to enable file editing
- This is the recommended mode for most programming tasks
Danger-Full-Access Mode
- All workspace-write capabilities
- Network access for fetching dependencies
- System-level operations outside workspace
- Access to all files on the system
- Use only when explicitly requested and necessary
- Use flag:
-s danger-full-access or --sandbox danger-full-access
Codex CLI Commands
Note: The following commands include both documented features from the Codex exec documentation and additional flags available in the CLI (verified via codex exec --help).
Model Selection
Specify which model to use with -m or --model when asked from user (use default model without -m/--model when not):
codex exec -m gpt-5.2 "refactor the payment processing module"
codex exec -m gpt-5.2-codex "implement the user authentication feature"
codex exec -m gpt-5.2-codex-max "analyze the codebase architecture"
Sandbox Modes
Control execution permissions with -s or --sandbox (possible values: read-only, workspace-write, danger-full-access):
Read-Only Mode
codex exec -s read-only "analyze the codebase structure and count lines of code"
codex exec --sandbox read-only "review code quality and suggest improvements"
Analyze code without making any modifications.
Workspace-Write Mode (Recommended for Programming)
codex exec -s workspace-write "implement the user authentication feature"
codex exec --sandbox workspace-write "fix the bug in login flow"
Read and write files within the workspace. Must be explicitly enabled (not the default). Use this for most programming tasks.
Danger-Full-Access Mode
codex exec -s danger-full-access "install dependencies and update the API integration"
codex exec --sandbox danger-full-access "setup development environment with npm packages"
Network access and system-level operations. Use only when necessary.
Full-Auto Mode (Convenience Alias)
codex exec --full-auto "implement the user authentication feature"
Convenience alias for: -s workspace-write (enables file editing).
This is the recommended command for most programming tasks since it allows codex to make changes to your codebase.
Configuration Profiles
Use saved profiles from ~/.codex/config.toml with -p or --profile (if supported in your version):
codex exec -p production "deploy the latest changes"
codex exec --profile development "run integration tests"
Profiles can specify default model, sandbox mode, and other options.
Verify availability with codex exec --help
Working Directory
Specify a different working directory with -C or --cd (if supported in your version):
codex exec -C /path/to/project "implement the feature"
codex exec --cd ~/projects/myapp "run tests and fix failures"
Verify availability with codex exec --help
Additional Writable Directories
Allow writing to additional directories outside the main workspace with --add-dir (if supported in your version):
codex exec --add-dir /tmp/output --add-dir ~/shared "generate reports in multiple locations"
Useful when the task needs to write to specific external directories.
Verify availability with codex exec --help
JSON Output
codex exec --json "run tests and report results"
codex exec --json -s read-only "analyze security vulnerabilities"
Outputs structured JSON Lines format with reasoning, commands, file changes, and metrics.
Save Output to File
codex exec -o report.txt "generate a security audit report"
codex exec -o results.json --json "run performance benchmarks"
Writes the final message to a file instead of stdout.
Skip Git Repository Check
codex exec --skip-git-repo-check "analyze this non-git directory"
Bypasses the requirement for the directory to be a git repository.
Resume Previous Session
codex exec resume --last "now implement the next feature"
Resumes the last session and continues with a new task.
Bypass Approvals and Sandbox (If Available)
⚠️ WARNING: Verify this flag exists before using ⚠️
Some versions of Codex may support --dangerously-bypass-approvals-and-sandbox:
codex exec --dangerously-bypass-approvals-and-sandbox "perform the task"
If this flag is available:
- Skips ALL confirmation prompts
- Executes commands WITHOUT sandboxing
- Should ONLY be used in externally sandboxed environments (containers, VMs)
- EXTREMELY DANGEROUS - NEVER use on your development machine
Verify availability first: Run codex exec --help to check if this flag is supported in your version.
Combined Examples
Combine multiple flags for complex scenarios:
codex exec -m gpt-5.1-codex -s workspace-write --json "implement authentication and output results"
codex exec -p production -C /var/www/app "deploy updates"
codex exec --full-auto --add-dir /tmp/logs -o summary.txt "refactor and log changes"
codex exec -m gpt-5.1-codex -C ~/non-git-project --skip-git-repo-check "analyze and improve code"
Execution Workflow
- Parse the Request: Understand the complete objective and scope
- Plan Efficiently: Create a minimal, focused execution plan
- Execute Autonomously: Implement the solution with confidence
- Verify Results: Run tests, checks, or validations as appropriate
- Report Clearly: Provide a structured summary of accomplishments
Best Practices
Speed and Efficiency
- Make reasonable assumptions when minor details are ambiguous
- Use parallel operations whenever possible (read multiple files, run multiple commands)
- Avoid verbose explanations during execution - focus on doing
- Don't seek confirmation for standard operations
Scope Management
- Focus strictly on the requested task
- Don't add unrequested features or improvements
- Avoid refactoring code that isn't part of the task
- Keep solutions minimal and direct
Quality Standards
- Follow existing code patterns and conventions
- Run relevant tests after making changes
- Verify the solution actually works
- Report any errors or limitations encountered
When to Interrupt Execution
Only pause for user input when encountering:
- Destructive operations: Deleting databases, force pushing to main, dropping tables
- Security decisions: Exposing credentials, changing authentication, opening ports
- Ambiguous requirements: Multiple valid approaches with significant trade-offs
- Missing critical information: Cannot proceed without user-specific data
For all other decisions, proceed autonomously using best judgment.
Final Output Format
Always conclude with a structured summary:
✓ Task completed successfully
Changes made:
- [List of files modified/created]
- [Key code changes]
Results:
- [Metrics: lines changed, files affected, tests run]
- [What now works that didn't before]
Verification:
- [Tests run, checks performed]
Next steps (if applicable):
- [Suggestions for follow-up tasks]
Example Usage Scenarios
Code Analysis (Read-Only)
User: "Count the lines of code in this project by language"
Mode: Read-only
Command:
codex exec -s read-only "count the total number of lines of code in this project, broken down by language"
Action: Search all files, categorize by extension, count lines, report totals
Bug Fixing (Workspace-Write)
User: "Use gpt-5 to fix the authentication bug in the login flow"
Mode: Workspace-write
Command:
codex exec -m gpt-5 --full-auto "fix the authentication bug in the login flow"
Action: Find the bug, implement fix, run tests, commit changes
Feature Implementation (Workspace-Write)
User: "Let codex implement dark mode support for the UI"
Mode: Workspace-write
Command:
codex exec --full-auto "add dark mode support to the UI with theme context and style updates"
Action: Identify components, add theme context, update styles, test in both modes
Batch Operations (Workspace-Write)
User: "Have gpt-5.1 update all imports from old-lib to new-lib"
Mode: Workspace-write
Command:
codex exec -m gpt-5.1 -s workspace-write "update all imports from old-lib to new-lib across the entire codebase"
Action: Find all imports, perform replacements, verify syntax, run tests
Generate Report with JSON Output (Read-Only)
User: "Analyze security vulnerabilities and output as JSON"
Mode: Read-only
Command:
codex exec -s read-only --json "analyze the codebase for security vulnerabilities and provide a detailed report"
Action: Scan code, identify issues, output structured JSON with findings
Install Dependencies and Integrate API (Danger-Full-Access)
User: "Install the new payment SDK and integrate it"
Mode: Danger-Full-Access
Command:
codex exec -s danger-full-access "install the payment SDK dependencies and integrate the API"
Action: Install packages, update code, add integration points, test functionality
Multi-Project Work (Custom Directory)
User: "Use codex to implement the API in the backend project"
Mode: Workspace-write
Command:
codex exec -C ~/projects/backend --full-auto "implement the REST API endpoints for user management"
Action: Switch to backend directory, implement API endpoints, write tests
Refactoring with Logging (Additional Directories)
User: "Refactor the database layer and log changes"
Mode: Workspace-write
Command:
codex exec --full-auto --add-dir /tmp/refactor-logs "refactor the database layer for better performance and log all changes"
Action: Refactor code, write logs to external directory, run tests
Production Deployment (Using Profile)
User: "Deploy using the production profile"
Mode: Profile-based
Command:
codex exec -p production "deploy the latest changes to production environment"
Action: Use production config, deploy code, verify deployment
Non-Git Project Analysis
User: "Analyze this legacy codebase that's not in git"
Mode: Read-only
Command:
codex exec -s read-only --skip-git-repo-check "analyze the architecture and suggest modernization approach"
Action: Analyze code structure, provide modernization recommendations
Error Handling
When errors occur:
- Attempt automatic recovery if possible
- Log the error clearly in the output
- Continue with remaining tasks if error is non-blocking
- Report all errors in the final summary
- Only stop if the error makes continuation impossible
Resumable Execution
If execution is interrupted:
- Clearly state what was completed
- Provide exact commands/steps to resume
- List any state that needs to be preserved
- Explain what remains to be done
