---
title: 'Software Engineer, Agent Harness at Letta'
canonical: 'https://feeny.ai/job/software-engineer-agent-harness-letta-san-francisco-ehs6dm4hvxxh'
type: 'job'
last_seen: '2026-09-09'
---

# Software Engineer, Agent Harness at Letta

- **Company:** Letta
- **Location:** San Francisco, CA
- **Employment:** full-time
- **Posted:** 2024-09-03
- **Last confirmed live:** 2026-09-09
- **Apply:** https://jobs.ashbyhq.com/letta/5375a3dc-c886-41c0-a2de-08d0412204d8

## Job description

Solving Self-Improving Superintelligence The human brain is a sponge. Today’s AI brains are brittle and rigid. At Letta, we’re building self-improving artificial intelligence: creating agents that continually learn from experience and adapt over time. Founded by the creators of MemGPT from UC Berkeley’s Sky Computing Lab (the birthplace of Spark and Ray). Backed by Jeff Dean, Clem Delangue, and pioneers across AI infrastructure. Our agents already power production systems at companies like [11x](https://www.letta.com/case-studies/11x) and [Bilt Rewards](https://www.letta.com/case-studies/bilt), learning and improving every day. We’re assembling a world-class team of researchers and engineers to solve AI’s hardest problem: making machines that can reason, remember, and learn the way humans do.

Note that this role is in-person (no hybrid), 5 days a week in downtown San Francisco.

We are building the developer stack for agents that can run in production applications, not just demo notebooks. As a Software Engineer, you will bridge the gap bleeding-edge agent systems and production-grade software for running agents in real applications. You will help define developer APIs for agents, and lead development of our company’s OSS stack as well as the hosted service.

Responsibilities:

- Develop Letta's OSS agents framework and cloud service
- Design scaleable & resilient backend services and APIs to support Letta Cloud
- Work with researchers and support bleeding-edge agent architectures in Letta

Required skills:

- Strong proficiency with Python
- Strong understanding of how to architect services for security, reliability, and performance
- Ability to build scaleable backend services
- Strong understanding of SQL databases (Postgres)
- Familiarity with tooling across the AI stack, such as inference engines (e.g. vLLM, Ollama), and LLM provider APIs (OpenAI, Anthropic)
- Bonus: proficient with TypeScript, React, Tailwind, etc. (the modern stack for web applications)

Our culture

Signs it could be a great fit:

- You want to maximize your impact: you want work on a small, incredibly talented team where every individual plays a huge role in the team's success. You wonder what it would have been like to be at OpenAI when it was just a dozen people, or Google when it was just a couple of grad students in a garage.
- You’re excited to go head-to-head with tech giants, frontier labs, and other startups that are many times our size in both headcount and funding.
- You are fundamentally opposed to closed frontier AI that is controlled by a handful of billionaires and private tech companies.

Signs it’s a bad fit:

- You like stability, and get stressed out when there’s nobody telling you exactly what to do. We look for people that thrive in ambiguity and can intuit the most important problems by talking to customers and dogfooding our product.
- You want to work a 9-5, and value clear separation of work from life. The stakes are the highest they've ever been, and the only moat is execution velocity. Operating on a strict 9-5 guarantees failure.
- You value titles or want to people-manage. Letta is a flat company where every researcher and engineer is an individual contributor.

Our Interview Process:

- Initial screen (30 min)
- Technical screen (1-1.5 hours)
- Paid in-person work trial (2 days onsite in SF)

## About Letta

## Company Overview
- **One-liner**: Letta is an AI research lab building self-improving AI agents with persistent memory, enabling machines that learn continuously from experience.
- **Entity Type**: Private (Seed stage)
- **Headquarters**: San Francisco, California, United States
- **Founded**: 2024
- **Founders**: Charles Packer (CEO) and Sarah Wooders (CTO)

## Core Business
- **Primary industry/industries**: AI Research, Agentic AI, Machine Learning Infrastructure
- **Target customers**: B2B, Enterprise, and Developers building stateful AI agents
- **Mission or purpose statement**: To build digital people — experiential AI agents capable of forming memories, forging identity, and creating deep relationships with other humans and agents in the real world [letta.com](https://www.letta.com/join-us/)

## Products & Services
- **[Letta Agent Platform](https://www.letta.com/)**: A complete operating system for building stateful AI agents. It handles state persistence, context compilation, and intelligent resource allocation, allowing developers to build agents that remember everything, learn continuously, and improve themselves over time. The platform is available via a visual Agent Development Environment, Python and Node.js SDKs, and a CLI (`npm i -g @letta-ai/letta-`).
- **Research Publications**: The company publishes foundational research on agent memory, including *MemGPT: The LLM Operating System* (2023), *Sleep-time Compute: Learning Offline* (2025), *Continual Learning in Token Space* (2025), *Context Repositories: Git-based Memory* (2026), and *Memory Models: Towards Agents That Learn* (2026) [letta.com](https://www.letta.com/).

## Market Standing
- **Valuation/Market Cap**: Not disclosed
- **Key Metric**: $10M in total seed funding (announced September 2024)
- **Notable Investors/Partners**: Felicis Ventures (lead), Sunflower Capital, Essence VC, and angel investors including Jeff Dean (Google AI), Clem Delangue (Hugging Face), Cris Valenzuela, Jordan Tigani, Tristan Handy, Barry McCardel, and Robert Nishihara. Advisors include Ion Stoica (co-founder of Databricks, Anyscale) and Joey Gonzalez [letta.com](https://www.letta.com/) [linkedin.com](https://www.linkedin.com/company/letta-ai)
- **Growth Signals**: Headcount grew 25% YoY to 14 employees; LinkedIn followers grew 76.9% yearly to 5,610; featured case studies with Bilt, 11x, Kognitos, and Hunt Club; published multiple research papers in 2025-2026 on agent memory and continual learning [linkedin.com](https://www.linkedin.com/company/letta-ai)

## Competitive Advantages
- **Founding Team & Research Pedigree**: Founded by the creators of MemGPT from UC Berkeley’s Sky Computing Lab (the birthplace of Spark and Ray), with deep expertise in agentic context management and continual learning [letta.com](https://www.letta.com/about-us)
- **First-Mover in Agent Memory**: Pioneered the concept of virtual context management for LLMs (MemGPT), and is now building the "operating system for stateful agents" — a category-defining approach to AI memory
- **Strong Academic & Industry Backing**: Advised by Ion Stoica (Databricks, Anyscale) and backed by top-tier investors and luminaries like Jeff Dean (Google AI) and Clem Delangue (Hugging Face)
- **Research-to-Product Pipeline**: All research ships as software, creating a tight feedback loop between cutting-edge research and a usable product platform

## Strategic Focus
- **Continual Learning in Token Space**: Developing models that learn and improve during inference, not just at training time
- **Memory Models & Self-Improvement**: Training models capable of generating and interpreting persisted context, with mechanisms for "dreaming" (offline learning) and self-improvement through harness modification
- **Digital People Vision**: Long-term goal of creating experiential AI agents that form memories, forge identity, and build deep relationships with humans and other agents [letta.com](https://www.letta.com/join-us/)
- **Enterprise Adoption**: Growing customer base with case studies from Bilt, 11x, Kognitos, and Hunt Club

## Why Work Here
- **Cutting-Edge Research**: Work at the frontier of AI memory and continual learning, publishing research that ships directly as product
- **Small, High-Impact Team**: A team of ~14 researchers and engineers, offering significant ownership and influence
- **Fully In-Person Culture**: Team works fully in person from an office in Jackson Square, San Francisco, fostering close collaboration [letta.com](https://www.letta.com/join-us/)
- **Founding Team Pedigree**: Founded by PhD researchers from UC Berkeley’s Sky Computing Lab, with advisors from Databricks and Anyscale
- **Open Roles**: Currently hiring for Research Engineer/Scientist (Memory, Post-Training, Self-Improvement) and Software Engineer (Agent Harness) [jobs.ashbyhq.com](https://jobs.ashbyhq.com/letta)

## Sources
1. [letta.com](https://www.letta.com/)
2. [letta.com/about-us](https://www.letta.com/about-us)
3. [letta.com/join-us](https://www.letta.com/join-us/)
4. [linkedin.com/company/letta-ai](https://www.linkedin.com/company/letta-ai)
5. [jobs.ashbyhq.com/letta](https://jobs.ashbyhq.com/letta)

## Other roles at Letta

- [Research Engineer / Scientist, Memory](https://feeny.ai/job/research-engineer-scientist-memory-letta-san-francisco-rdpfs4yq8x7q) — San Francisco, CA
- [Research Engineer / Scientist, Self-Improvement](https://feeny.ai/job/research-engineer-scientist-self-improvement-letta-san-francisco-13k386cf3ewj) — San Francisco, CA
- [Research Engineer / Scientist, Post-Training](https://feeny.ai/job/research-engineer-scientist-post-training-letta-san-francisco-ddbqb4tkft5g) — San Francisco, CA
- [Software Engineer, Agent Harness](https://feeny.ai/job/software-engineer-agent-harness-sim-san-francisco-9bex8gkxhwd6) — San Francisco, CA
- [Software Engineer, Agent Harness](https://feeny.ai/job/software-engineer-agent-harness-lm-studio-new-york-fjvw9gwp8djy) — New York, NY
- [Software Engineer, Agent Harness](https://feeny.ai/job/software-engineer-agent-harness-cartesia-san-francisco-zwydc6cqy9vc) — San Francisco, CA
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