Codebase analysis using Codex CLI with read-only sandbox. Trigger when user needs architecture overview ("analyze this codebase with Codex", "have Codex map dependencies"), onboarding to unfamiliar code, understanding legacy systems, or identifying technical debt.
View on GitHubrobbyt/claude-skills
codex
January 15, 2026
Select agents to install to:
npx add-skill https://github.com/robbyt/claude-skills/blob/main/plugins/codex/skills/codebase-analysis/SKILL.md -a claude-code --skill codebase-analysisInstallation paths:
.claude/skills/codebase-analysis/# Codebase Analysis via Codex
Use Codex for codebase analysis with read-only sandbox.
## CRITICAL: Instruct Codex
Every prompt sent to Codex MUST include these instructions:
> "You are running non-interactively as part of a script. Do not ask questions or wait for input. Do not make any changes. Provide your complete analysis immediately."
Codex is a consultant. Claude Code handles all file modifications.
## Quick Start (MCP)
If the `codex` MCP tool is available, use it directly:
```
mcp__plugin_codex_cli__codex({
"prompt": "You are running non-interactively as part of a script. Do not ask questions or wait for input. Do not make any changes. Provide your complete analysis immediately.\n\nAnalyze this project structure and architecture.",
"sandbox": "read-only",
"model": "gpt-5.2"
})
```
## Fallback (Bash)
If MCP is unavailable, use shell command:
```bash
codex exec "You are running non-interactively as part of a script. Do not ask questions or wait for input. Do not make any changes. Provide your complete analysis immediately.
Analyze this project structure and architecture." --sandbox read-only -m gpt-5.2-codex 2>&1
```
## When to Use
- Onboarding to unfamiliar codebases
- Understanding legacy systems
- Mapping component relationships
- Finding hidden dependencies
- Architecture documentation
- Technical debt assessment
## Examples
**Full project analysis:**
```
mcp__plugin_codex_cli__codex({
"prompt": "You are running non-interactively as part of a script. Do not ask questions or wait for input. Do not make any changes. Provide your complete analysis immediately.\n\nAnalyze this project. Report on:\n- Overall architecture\n- Key dependencies\n- Component relationships\n- Potential issues",
"sandbox": "read-only",
"model": "gpt-5.2"
})
```
**Flow mapping:**
```
mcp__plugin_codex_cli__codex({
"prompt": "You are running non-interactively as part of a script. Do not ask questions or wait for input. Do not make any changes. Provide your