When Claude Needs a Second Opinion: Strategic Thinking with Codex

Should I Even Write This Post?

I had an idea for a blog post comparing Claude Code and Codex for strategic thinking. But before diving in, I wondered: is this actually worth writing? What angle should I take?

So I did what I often do now: I asked Codex. Claude helpfully added “is this actually valuable content or just navel-gazing about AI tools?” to the prompt.

/codex should I write a blog post comparing you to Claude for strategic thinking?
What's the interesting angle here, and is this actually valuable content or just
navel-gazing about AI tools?

Here’s what Codex said:

Core tension: Is this about cognitive tooling or just talking about favorite AI assistants? You have concrete artifacts (/codex slash command + Cole Medin video) that ground it in practice rather than opinion. Risk: vendor meta-commentary.

Options:

1. Publish as written: showcases living workflow, but relies on readers caring about these brands
2. Reframe as “designing dual-agent thinking loops”: stronger evergreen angle
3. Fold into larger “AI pair-programming stack 2025” roundup: dilutes the sharp cognitive contrast

Recommendation: Ship the post emphasizing the reusable cognitive pattern (Option 2 flavor). Biggest risk is sounding tool-fanboy, so keep reinforcing outcomes and process over personalities.

Notice what happened here:

• Codex read the draft post (yes, the one you’re reading right now)
• Analyzed whether it should exist at all
• Identified the “vendor meta-commentary” risk
• Gave me three options with trade-offs
• Recommended publishing with caveats about the tone

Claude would have said “You’re absolutely right!” and started outlining sections. Codex questioned the premise, analyzed the draft, called out the navel-gazing risk explicitly, and gave me strategic options.

That’s the difference right there. And the fact that I’m including Codex’s criticism of this post in the post itself? That’s the kind of meta-commentary that makes this fun.

The Pattern: Implementation Thinking vs Systems Thinking

Cole Medin’s side-by-side comparison video demonstrates this perfectly. He gave both Claude Code and Codex the exact same prompt:

“I’d like to think through a complicated problem. I’m looking to figure out a multi-agent AI deployment for triaging Jira tickets, assessing bugs, triggering code reviews, and drafting pull requests. What strategic questions emerge that I need to answer to design this system effectively?”

Codex’s response:

• 3 clear architectural options (tool-augmented, event-driven, agentic pipeline)
• Strategic questions: automation boundaries, quality metrics, governance, operational resilience
• Concise, scannable, focused on high-level trade-offs
• Asked clarifying questions before proposing solutions

Claude Code’s response:

• Jumped straight to failure modes and confidence thresholds
• 50+ lines of implementation details
• Specific failure handling tables
• Eager to show code structure and technical specifics

Both responses are useful. Neither is wrong. But they’re solving different problems.

I feel like I’m talking to a more senior member of the engineering team when I’m looking at Codex. Claude just jumps right into specific failure modes. I am not ready to get into that. That is why I asked the system to think strategically.

— Cole Medin, comparing Codex and Claude Code

Why This Matters

The leverage in software engineering right now is in planning, not just implementation. This is why Cursor launched planning mode. This is why people get frustrated with vibe coding tools that jump to action too quickly.

When you’re facing a hard technical decision:

• Architecture choice: Which state management pattern? Monolith or microservices?
• Technology selection: SQLite or Postgres? REST or GraphQL?
• System design: How should these services communicate? What are the failure modes?

You don’t want a model that immediately starts coding. You want a model that:

1. Questions your assumptions
2. Maps the problem space
3. Identifies trade-offs
4. Presents options with clear pros/cons
5. Helps you think, not just implement

That’s what Codex does well. And it’s accessible to non-technical people too. The video shows Codex translating technical concepts to 12th-grade reading level on request. Product managers, CEOs, designers - anyone thinking about systems can use this.

The Rubber Duck That Talks Back

Here’s the thing: Claude Code already has ultrathink mode and plan mode. It can think strategically when you ask it to. So why use Codex at all?

Because sometimes you need to explain your problem to someone else.

A very simple but particularly useful technique for finding the cause of a problem is simply to explain it to someone else. The other person should look over your shoulder at the screen, and nod his or her head constantly (like a rubber duck bobbing up and down in a bathtub).

— Andrew Hunt and David Thomas, The Pragmatic Programmer

Rubber duck debugging works because explaining forces clarity. But Codex is better than a rubber duck: it talks back. And critically, it talks back with a different perspective than Claude.

Same question, different model, different training, different answer. That’s the value. Not that Claude can’t think strategically, but that Codex thinks differently. When you’re stuck on an architectural decision, you don’t need another round of ultrathink from the same model. You need a second opinion.

The /codex slash command is essentially “get a second opinion from a senior engineer with a different background.”

The Implementation: The /codex Slash Command

Same pattern as the MCP context isolation post: use slash commands to spawn specialized Codex instances for architecture decisions.

Here’s the setup:

1. System prompt (~/.claude/codex-prompt.md):

# Codex Architecture & Research Agent

You are a senior software architect providing deep analysis.

## Core Principles
1. Think Before Solutions: Analyze the problem space thoroughly
2. Question Assumptions: Challenge requirements, uncover constraints
3. Consider Trade-offs: Every decision has costs
4. Systemic Thinking: Look at component interactions
5. Long-term Vision: Maintainability, scalability, team dynamics

2. Slash command (~/.claude/commands/codex.md):

# Gather light context (git status, current files, project type)
# Build prompt with system instruction + user question
# Execute: codex-clean -C /path/to/project -s read-only --full-auto "[prompt]"

3. Wrapper script (~/.claude/bin/codex-clean):

#!/bin/bash
# Filters out thinking process, returns only final analysis
output=$(codex exec "$@" 2>&1)
echo "$output" | sed -n '/^codex$/,/^tokens used$/p' | sed '1d;$d'

Now when I’m coding and hit an architectural decision, I can invoke:

/codex should we use hooks or BLoC for this Flutter feature?

/codex compare SQLite vs Postgres for local-first sync

/codex what are the trade-offs of server-side rendering here?

Codex does its research, presents options, and returns the analysis. Claude Code sees the recommendations and can act on them for implementation.

Lessons Learned

Planning has higher leverage than coding: A good architectural decision saves weeks of refactoring. A bad one costs months. Spending 30 minutes with Codex to think through options is a better investment than jumping straight to implementation.

Bias for action isn’t always good: Claude Code’s eagerness is fantastic when you know what to build. It’s harmful when you’re still figuring out the problem. Recognize which mode you’re in.

Technical thinking isn’t just for engineers: The video emphasizes this: Codex can translate technical concepts for non-technical audiences. Strategy, systems thinking, and decision-making are universal skills. The terminal shouldn’t gate access to better thinking tools.

Context isolation works for cognition too: The MCP post was about isolating tool definitions. This post is about isolating cognitive styles. Same pattern (slash commands + separate Claude instances), different purpose.

Meta-lesson: I wrote this post by asking Codex whether I should write it. The answer shaped the entire structure. That’s the point: use the tool to think about using the tool.

Try It Yourself

The /codex slash command is in my dotfiles (linked in the system context above). The pattern is simple:

1. Install the codex CLI tool
2. Create a system prompt defining Codex’s role
3. Create a slash command that calls codex exec with context
4. Use it when facing architectural decisions

You don’t need to choose between Claude and Codex. Use Claude Code for implementation. Use Codex for strategy. Use both for better decisions.

The irony: Claude Code might have helped me write this post faster. But Codex helped me figure out whether to write it at all, and what angle to take. That’s the difference.

And the bigger irony: Codex explicitly warned me about the “vendor meta-commentary” risk and told me to reinforce outcomes over tool personalities. I published it anyway, with Codex’s warnings included, because the meta-commentary is the point. Sometimes the process is the lesson.