Chief of Staff (+ Equity) at Mobius
People & HR, Operations · Full-time
San Francisco, CA, USA
Posted on Sep 3, 2026
This is a job that Jill, our AI Recruiter, is recruiting for on behalf of one of our customers.
She will pick the best candidates from Jack's network.
The next step is to speak to Jack.
Job Title
Chief of Staff
Salary
Not Disclosed + Equity
Company Description
Mobius is a $5M pre-seed San Francisco startup building the critical infrastructure and high-quality reinforcement learning data required by frontier AI labs and enterprises.
Job Description
As the Chief of Staff at Mobius, you will serve as the CEO's right hand in building a category-defining AI infrastructure company. You will bridge the gap between technical research and business operations, shaping product strategy and scaling internal systems. This founding-team role offers direct exposure to the forefront of LLM post-training and agentic RL.
Location
San Francisco, USA
Why this role is remarkable
Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
How does this work?
This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.
Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.
We appreciate this can make them look a bit suspect, but there isn't much we can do about it.
Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.
She will pick the best candidates from Jack's network.
The next step is to speak to Jack.
Job Title
Chief of Staff
Salary
Not Disclosed + Equity
Company Description
Mobius is a $5M pre-seed San Francisco startup building the critical infrastructure and high-quality reinforcement learning data required by frontier AI labs and enterprises.
Job Description
As the Chief of Staff at Mobius, you will serve as the CEO's right hand in building a category-defining AI infrastructure company. You will bridge the gap between technical research and business operations, shaping product strategy and scaling internal systems. This founding-team role offers direct exposure to the forefront of LLM post-training and agentic RL.
Location
San Francisco, USA
Why this role is remarkable
- Work directly with CEO Sijun, a UC Berkeley PhD specialist in agentic RL, at the intersection of AI research and infrastructure.
- Join a well-funded $5M pre-seed team solving the data bottleneck for the world's most advanced frontier AI labs and enterprises.
- Massive impact as a founding-team member with equity, helping build the company's operating systems and strategy from the ground up.
- Partner with the CEO on high-level research and product strategy to define the future of RL data curation.
- Own end-to-end business operations, managing day-to-day internal processes and coordinating between research teams and external partners.
- Build and implement scalable organizational systems that facilitate rapid growth and ensure seamless delivery to frontier AI clients.
- Proven experience as a versatile operator-strategist, ideally in a Chief of Staff, strategy consulting, or high-growth startup environment.
- Strong intellectual curiosity and the ability to engage deeply with a technical team focused on LLM post-training and agentic RL.
- Exceptional builder mindset with the ability to navigate early-stage ambiguity and take full ownership of company-wide internal functions.
Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
How does this work?
- Jack's an AI agent for job searching and career coaching. He works for you.
- Jill is the AI recruiter working for the company. She recruits from Jack's network.
- If it's a match and the company wants to meet you, they'll make the intro. In the meantime, if you'd like, Jack will send you excellent alternatives.
This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.
Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.
We appreciate this can make them look a bit suspect, but there isn't much we can do about it.
Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.