Immutable. This exact content is served forever at /api/v1/blob/8acc18832ca9af86.
---
name: code-investigate
description: "Dual-perspective code investigation. Use when: deep code analysis needing both Claude and Codex perspectives. Not for: quick exploration (use code-explore), code review (use codex-code-review). Output: integrated findings from dual analysis."
allowed-tools: Read, Grep, Glob, Bash(git:*), Bash(node:*), Write
context: fork
---
# Code Investigate Skill
## Trigger
- Keywords: investigate code, how feature works, trace implementation, dual confirmation, deep dive, how code works, what this code does, code research
## When NOT to Use
- Just need quick lookup (use Grep/Glob directly)
- Code review (use codex-review)
- System verification (use feature-verify)
- Git history tracking (use git-investigate)
## Core Principle
```
Codex must explore independently. Feeding Claude's conclusions to Codex is prohibited.
```
```
┌─────────────────┐ ┌─────────────────┐
│ Claude Explores │ │ Codex Explores │
│ Independently │ │ Independently │
│ (Phase 1-2) │ │ (Phase 3) │
└────────┬────────┘ └────────┬────────┘
│ │
▼ ▼
┌───────────┐ ┌───────────┐
│ Claude │ │ Codex │
│ Conclusion│ │ Conclusion│
└─────┬─────┘ └─────┬─────┘
│ │
└───────────┬───────────┘
▼
┌─────────────┐
│ Consolidated│
│ Report │
│ (Phase 4) │
└─────────────┘
```
## Workflow
| Phase | Name | Action | Output |
| ----- | --------------- | ----------------------------------- | --------------------------- |
| 1 | Claude Explore | Grep/Glob/Read to search code | Related files list |
| 2 | Claude Conclude | Analyze logic, form understanding | Initial conclusion (internal)|
| 3 | Codex Explore | Invoke Codex exec to explore independently | Codex analysis report |
| 4 | Integrate | Compare both perspectives, mark differences | Consolidated report |
## Codex Invocation Rules
Dispatch Phase 3 per `@skills/codex-code-review/references/codex-transport.md` § Start with the template in `references/prompts.md`. The transport
pins the sandbox and the approval policy, and it derives the working directory from
`git rev-parse --show-toplevel` — none of the three is chosen here, and this skill no longer
restates them.
**Bind every placeholder before writing `prompt.md`.** The template is body-only, so nothing
evaluates an expression inside it: `${USER_QUESTION}` and `${PROJECT_PATH}` must carry real values
by the time the file is written.
### Correct Approach
## Code Investigation Task
## Question
${USER_QUESTION}
## Project Info
- Path: ${PROJECT_PATH}
- Tech Stack: ${TECH_STACK} <!-- one bound value, read from the repository's own manifest and layout. `{FRAMEWORK}`/`{DATABASE}` were never in this file's binding contract and rendered literally, and the hard-coded `TypeScript` was false for any repository that is not one — this project is JavaScript. Omit the line entirely rather than guess. -->
Please **independently explore** the codebase and answer:
1. What files are related?
2. How does the core logic work?
3. What is the data flow?
4. What are the key dependencies?
Please grep/read and explore on your own, then provide your analysis.
### Prohibited Approaches
| Pattern | Problem | Example |
| ------------------ | --------------------------------- | ------------------------------------------- |
| Feeding conclusion | Claude's findings leak to Codex | `Claude found these files: ${findings}` |
| Leading question | Presupposes answer | `I think the problem is in cache, verify` |
| Scope restriction | Prevents independent exploration | `Only look at src/service/` |
## Output
```markdown
## Investigation Report
- **Claude findings**: <independent analysis>
- **Codex findings**: <independent analysis>
- **Integrated conclusion**: <merged findings>
- **Confidence**: High / Medium / Low
```
## Verification Checklist
| Check | Standard |
| ------------------------- | --------------------------------------------- |
| Claude independent conclusion | Phase 2 forms conclusion, not output to user |
| Codex prompt is clean | Contains only question + project path, no Claude findings |
| Report perspectives separated | Claude / Codex conclusions presented separately |
| Integration is complete | Marks agreement, differences, possible gaps |
## References
| File | Purpose | When to Read |
| ------------------------------- | -------------------- | ------------------ |
| `references/prompts.md` | Codex prompt templates | Before Phase 3 |
| `references/output-template.md` | Report format | During Phase 4 |
## Examples
### Feature Investigation
```
Input: Investigate how order processing works
Phase 1: Grep "processOrder" -> Read src/service/order/*.ts
Phase 2: Form understanding: Controller -> Service -> Repository write
Phase 3: Codex explores independently (only given question + path)
Phase 4: Consolidated report -> mark both perspectives
```
### Mechanism Understanding
```
Input: How does the API caching mechanism work?
Phase 1: Grep "cache" + "portfolio" -> Read related files
Phase 2: Understand Redis TTL + fallback mechanism
Phase 3: Codex investigates independently
Phase 4: Compare differences -> output consolidated report
```
### Problem Diagnosis
```
Input: Why is token price sometimes null?
Phase 1: Search price-related logic + error handling
Phase 2: Identify possible fallback paths
Phase 3: Codex diagnoses independently
Phase 4: Synthesize both findings -> list possible causes
```