Codex Architect Skill (Third Brain)

Trigger

• Keywords: architecture design, solution evaluation, tech selection, third brain, Codex advice, design consulting, ask Codex, second opinion

When NOT to Use

• Code implementation (use /codex-implement)
• Code review (use /codex-review)
• Deep discussion/exhaustive exploration (use /codex-brainstorm)

Usage

/codex-architect "<question>"
/codex-architect "Evaluate this design" --context src/xxx.ts --mode review
/codex-architect "Redis vs MongoDB?" --mode compare

Modes

Mode	Purpose	When
design	Provide design advice	Starting from scratch (default)
review	Evaluate existing design	Validate solution, find issues
compare	Compare multiple options	Tech selection

Core Principle

User -> Claude -> Codex -> Integrate
          |         |         |
    Initial thinking  Third perspective  Combined advice

Codex Prompt Template

When using mcp__codex__codex, must include the following:

mcp__codex__codex({
  prompt: `You are a senior architect. Please provide architecture advice for the following question.

## Question
${QUESTION}

## Mode
${MODE} (design/review/compare)

## IMPORTANT: You must independently research the project

Before providing architecture advice, you **must** perform the following research:

### Research Steps
1. Understand project structure: \`ls src/\`, \`ls src/service/\`, \`ls src/provider/\`
2. Search related modules: \`grep -r "keyword" src/ --include="*.ts" -l | head -10\`
3. Read existing implementations: \`cat <relevant files> | head -150\`
4. Understand existing architecture patterns and conventions

### Verification Focus
- What does the existing architecture look like?
- What are the existing code style and patterns?
- What similar features can be referenced?

## Output Requirements

1. First describe which files you researched
2. Provide advice based on current project state
3. Consider consistency with existing architecture

...(other review dimensions)`,
  sandbox: 'read-only',
  'approval-policy': 'never',
});

Workflow Integration

/codex-architect -> /tech-spec -> /review-spec -> /codex-implement -> /codex-review-fast
    Design           Plan          Review          Implement          Code Review

Verification

• Report includes Codex advice + Claude perspective
• Consensus and divergence points clearly marked
• Final recommendation integrates both perspectives

References

• references/project-knowledge.md - Project architecture knowledge + report template

Examples

Input: /codex-architect "How to design a high-concurrency cache?"
Action: Codex analysis -> Claude supplement -> Integrated output

Input: /codex-architect "Any issues with this API design?" --mode review
Action: Codex evaluation -> Claude verification -> Output issues + recommendations