Claude or ChatGPT? Mysti Lets You Use Both at the Same Time in VS Code

If you code regularly with AI assistants, you probably face the same daily dilemma:
Should I use Claude or ChatGPT for this tricky refactor?

Some days, one model nails architecture. Other days, the other one produces cleaner logic. But what if you didn’t have to choose?

That’s exactly the idea behind Mysti, a clever VS Code extension that takes AI-assisted development to the next level. Instead of relying on a single model, Mysti lets you run two AI coding models together—and even watch them debate your problem before generating a solution.

For complex refactoring, architecture planning, or security reviews, this approach can be surprisingly powerful.

What Is Mysti for VS Code?

Mysti is an extension for Visual Studio Code built around a simple but brilliant principle:

Why use one AI brain when you can use two?

Rather than embedding its own proprietary model, Mysti acts as an orchestrator. It connects to AI coding tools installed locally via CLI and coordinates their responses.

You can pair models like:

• Claude Code
• OpenAI Codex
• Gemini CLI

This means you’re not locked into one ecosystem—you’re building your own AI “dream team.”

Brainstorm Mode: Two AIs, One Problem

The standout feature is Brainstorm Mode.

Here’s how it works:

1. You select two AI models.
2. You provide your coding task (e.g., “Refactor this async API layer”).
3. Mysti launches both models on the same problem.
4. They analyze, critique, and refine ideas before producing a combined solution.

Instead of getting one immediate answer, you get a mini technical debate.

One model might suggest a performance-focused solution.
The other might emphasize readability or modular design.

The final output often merges the strengths of both.

It feels a bit like having two senior developers doing pair programming over your shoulder—without the office noise or cold coffee.

Full Mode: Watch the AI Debate

If you enable Full Mode, things get even more interesting.

You can literally see the models:

• Propose alternative implementations
• Challenge each other’s logic
• Suggest architectural trade-offs
• Improve each other’s code

For architectural work, this is where Mysti really shines. A single AI often “commits” to its first solution. Two models cross-checking each other reduce tunnel vision.

For complex refactoring, distributed systems, or large-scale structural changes, this can prevent subtle design mistakes.

Personas: Role-Based AI Coding

Mysti also includes 16 built-in Personas, letting you shape how your AI team behaves.

You can assign roles like:

• Architect – Focuses on structure and scalability
• Security-Minded – Reviews for vulnerabilities and best practices
• Performance Optimizer – Targets speed and efficiency
• Clean Code Advocate – Prioritizes readability and maintainability

This agent-style workflow is similar to approaches seen in emerging multi-agent coding tools, where specialized AI roles collaborate to produce higher-quality output.

Instead of asking for “better code,” you’re guiding how the AI thinks.

How to Install Mysti in VS Code

Installation is straightforward via the VS Code Marketplace:

ext install DeepMyst.mysti

However, there’s an important technical detail:

Mysti doesn’t run models directly. It orchestrates locally installed CLI tools. That means you must:

• Install the relevant CLI (e.g., Claude Code, Gemini CLI, etc.)
• Authenticate with your API keys
• Ensure your environment is properly configured

This design gives you flexibility—but also means your own API usage determines cost.

Token Usage: The Hidden Trade-Off

There’s one caveat.

Because Mysti relies on your personal API keys through CLI tools, running two models in discussion mode can increase token consumption significantly.

A short prompt may become:

• Initial response from Model A
• Critique from Model B
• Revised suggestion from Model A
• Final synthesis

That back-and-forth can multiply API usage.

If you’re running high-context sessions or working on large files, costs can climb quickly.

For architecture planning or critical refactoring, it’s absolutely worth it. For small bug fixes? Probably overkill.

Use it strategically.

When Mysti Is Most Useful

Mysti truly excels in:

• Large-scale refactoring
• System architecture design
• Security auditing
• Complex algorithm discussions
• Multi-layered backend restructuring

For quick snippets or simple CRUD endpoints, a single AI model may be faster and more cost-efficient.

But when the stakes are high—having a built-in “second opinion” can prevent expensive mistakes.

The Bigger Shift: Multi-Agent AI Development

Mysti represents something bigger than just a VS Code extension.

It reflects a shift toward multi-agent AI development, where collaboration between models produces better results than isolated prompts.

Instead of asking, “Which model is best today?”
You ask, “How can these models improve each other?”

For developers who already rely heavily on AI tools, that’s a meaningful evolution.

Final Thoughts: Should You Try Mysti?

If you frequently switch between Claude and ChatGPT for coding tasks, Mysti might feel like a natural upgrade.

It doesn’t replace your workflow—it enhances it.

• Better architectural thinking
• Reduced blind spots
• Stronger refactoring outcomes
• Role-based AI collaboration

Just remember: with great AI power comes great token consumption.

For serious development sessions, though?
Having two AI minds debating your code might be the smartest move you make all year.