Show HN: Mysti – Claude, Codex, and Gemini debate your code, then synthesize

Posted by bahaAbunojaim 12/23/2025

Show HN: Mysti – Claude, Codex, and Gemini debate your code, then synthesize(github.com)

Hey HN! I'm Baha, creator of Mysti.

The problem: I pay for Claude Pro, ChatGPT Plus, and Gemini but only one could help at a time. On tricky architecture decisions, I wanted a second opinion.

The solution: Mysti lets you pick any two AI agents (Claude Code, Codex, Gemini) to collaborate. They each analyze your request, debate approaches, then synthesize the best solution.

Your prompt → Agent 1 analyzes → Agent 2 analyzes → Discussion → Synthesized solution

Why this matters: each model has different training and blind spots. Two perspectives catch edge cases one would miss. It's like pair programming with two senior devs who actually discuss before answering.

What you get: * Use your existing subscriptions (no new accounts, just your CLI tools) * 16 personas (Architect, Debugger, Security Expert, etc) * Full permission control from read-only to autonomous * Unified context when switching agents

Tech: TypeScript, VS Code Extension API, shells out to claude-code/codex-cli/gemini-cli

License: BSL 1.1, free for personal and educational use, converts to MIT in 2030 (would love input on this, does it make sense to just go MIT?)

GitHub: https://github.com/DeepMyst/Mysti

Would love feedback on the brainstorm mode. Is multi-agent collaboration actually useful or am I just solving my own niche problem?

216 points | 178 commentspage 3

prashantsengar 12/27/2025|

This is very useful! I frequently copy the response of one model and ask another to review it and I have seen really good results with that approach.

Can you also include Cursor CLI for the brainstorming? This would allow someone to unlock brainstorming with just one CLI since it allows to use multiple models.

bahaAbunojaim 12/27/2025|

I’m planning to add Cursor and Cline in the next major release, will try to get in out in Jan

reachableceo 12/27/2025||

Please also add qwen cli support

bahaAbunojaim 12/27/2025||

Will do. I was thinking of also making the LLMs configurable across the agents. I saw a post from the founder of openrouter that you can use DeepSeek with Claude code and was thinking of making it possible to use more LLMs across agents

altmanaltman 12/27/2025||

> Would love feedback on the brainstorm mode. Is multi-agent collaboration actually useful or am I just solving my own niche problem?

If it's solving even your own niche problem, it is actually useful though right? Kind of a "yes or yes" question.

bahaAbunojaim 12/27/2025|

True and hearing feedback is always helpful and helps validate if it is a common problem or not

GajendraSahu23 12/28/2025||

This looks great! As someone just starting their coding journey, would using multiple agents (Claude/Gemini) help in learning best practices, or is it better suited for experienced developers for refactoring?

bahaAbunojaim 12/28/2025|

Thanks! You would need to instruct the agents to follow best practices and explain it while developing. Sometimes they get messy but if you use the right instructions/persona/skills then you will get very good results

A final review from experienced developers is always recommended

kundi 12/29/2025||

It sounds like an interesting experiment that you're doing. Are there any plans to support cli mode? Many developer are reluctant of VS code and other slow IDEs

bahaAbunojaim 12/29/2025|

We are actively working on it, hopefully will get something out in Jan with additional providers like cursor added

adiga1005 12/27/2025||

I have been using it for some time and it getting better and better with time in many cases it’s giving better output than other tools the comparison is great feature too keep up the good work

bahaAbunojaim 12/27/2025|

Thank you so much! Let me know if you face any issues and happy to address it

sorokod 12/27/2025||

Have you tried executing multiple agents on a single model with modified prompts and have them try to reach consensus?

That may solve the original problem of paying for three different models.

bahaAbunojaim 12/27/2025||

I think you will still pay for 3 times the tokens for a single model rather than 3 but will consolidate payment.

I was thinking to make the model choice more dynamic per agent such that you can use any model with any agent and have one single payment for all so you won’t repeat and pay for 3 or more different tools. Is that in line with what you are saying ?

sorokod 12/27/2025||

Neither the original issue (having three models) nor this one (un consolidated payments) have anything to do with the end result / quality of the output.

Can you comment on that?

bahaAbunojaim 12/27/2025|||

Executing multiple agents on the same model also works.

I find it helpful to even change the persona of the same agent “the prompt” or the model the agent is using. These variations always help but I found having multiple different agents with different LLMs in the backend works better

markab21 12/27/2025||

I love where you're going with this. In my experience it's not about a different persona, it's about constantly considering context that triggers, different activations enhance a different outcome. You can achieve the same thing, of course by switching to an agent with a separate persona, but you can also get it simply by injecting new context, or forcing the agent to consider something new. I feel like this concept gets cargo-culted a little bit.

I personally have moved to a pattern where i use mastra-agents in my project to achieve this. I've slowly shifted the bulk of the code research and web research to my internal tools (built with small typescript agents).. I can now really easily bounce between different tools such as claude, codex, opencode and my coding tools are spending more time orchestrating work than doing the work themselves.

bahaAbunojaim 12/27/2025||

Thank you and I do like the mantra-agents concept as well and would love to explore adding something similar in the future such that you can quickly create subagents and assign tasks to them

sorokod 12/27/2025|||

(BTW, givent token cashing your argument of 3 x 1 = 1 x 3 deserves more scrutiny)

bahaAbunojaim 12/27/2025||

That might be true but if you change the system instructions “which is at the beginning of the prompt” then caching doesn’t hit. So different agents would most likely skip caching unless the last prompt is different then you get the benefit of caching indeed

mmaunder 12/27/2025||

Yeah having codex eval its own commits is highly effective. For example.

bahaAbunojaim 12/27/2025||

I agree, I find it very helpful to ask agents to think using a different persona too

taf2 12/27/2025||

For me when it’s front end I usually work with Claude and have codex review. Otherwise I just work with codex… Claude also if I’m being lazy and want a thing quickly

bahaAbunojaim 12/27/2025|

Gemini is also great at frontends nowadays. I think every agent does have strengths and capabilities

NicoJuicy 12/27/2025||

Sounds very similar to LLM council

https://github.com/karpathy/llm-council

bahaAbunojaim 12/27/2025|

Thanks for sharing, I will check it out

omarkoudsi 12/28/2025||

I feel this is quite needed. I am beginner vibe coder and have already felt the need for this. I constantly shift back and forth.

bahaAbunojaim 12/28/2025|

Thank you so much and would love to hear your feedback anytime

justatdotin 12/28/2025|

multi-agent collaboration on planning is definitely really valuable. I lean in to gemini's long context and have it set up as a long-term observer who I consult about overall direction, project philosophy, patterns in fail and success, and prioritisation. This gives a different perspective from which to assess other agents' plans.

bahaAbunojaim 12/28/2025|

Very true, Claude also tend to struggle around the context window limit and after compact

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