tesslcareers - Member of Technical Staff- Research Engineer (Harness Engineering and Agentic Orchestration)
Requirements
• We're explicitly building coverage across four skill areas. You don't need to be strong in all of them — but you should bring depth in at least one: • Agent harness and orchestration design — how tools, context, and control flow combine to make a useful agent. • Agentic eval methodology — task and repo-level evals, dataset curation, the craft of measuring what actually matters. • Outer-loop and pipeline thinking — feedback loops, training-data flywheels, bandit-style optimisation, anything that goes beyond a single agent session. • Failure-mode analysis — instrumenting agents, reading traces at volume, surfacing patterns engineering can act on. • 4+ years shipping AI/ML products in a startup or applied industry setting, with recent hands-on experience with LLMs and agentic systems. • Demonstrated depth in at least one of the four skill areas above. • Strong product and customer instincts: comfort joining customer calls, watching session recordings, and letting real workflows shape what you work on. • Sharp evaluation judgement: benchmarks where they exist, vibes and quick prototypes where they don't, and the taste to know which is appropriate. • Experience building datasets for evaluation or training, including the pipeline work that goes with it. • Deeply curious about agents and excited about reshaping how software is built. • A Masters or PhD in a relevant computational field. • Direct experience with coding agents or code-generation systems. • Background in RL, bandits, or other outer-loop optimisation frameworks applied to LLMs. • Experience building synthetic data, dataset infrastructure, or internal tooling that other engineers actually used. • A project you can show us (GitHub links welcome) and a thoughtful answer to "Why Tessl?"
Responsibilities
• No two weeks will look the same. A flavour: • Sit in on a customer session, understand how their agents are failing, design an eval that captures it, and drive a fix through to shipped improvement. • Close a piece of the outer loop end to end: production signal in, dataset out, eval scored, harness change shipped, metric moved. • Own a slice of our eval infrastructure: dataset curation, harness configuration, runner, analysis, and the comms back to engineering. • Prototype a new harness or context configuration and measure whether it actually moves the needle on real customer tasks. • Dig through pages of agent traces, build the tooling you need to make sense of them, and brief the team on what you found. • Partner with product and engineering on near-term shipping problems by bringing research rigour. • Pull a recent paper apart, work out what's actually transferable to our platform, and turn it into a concrete experiment. • YOU’LL BE SUCCESSFUL IF…
Benefits
• Competitive salary commensurate with experience. Health insurance extending to partners and dependents, pension contributions, and the rest of what you'd expect. • Our office is a couple of minutes from King's Cross — pet friendly, with regular team lunches, drinks, and socials. We're hybrid, with Monday, Tuesday, and Thursday as the primary in-office days. • APPLICATION PROCESS • Intro call to understand "Why Tessl?" and to tell you a bit about us. • A call with our AI Research Lead to understand your ways of working and how you use agents. • A 4 hour technical take-home exercise extending our one-shot implementation. • A half-day on-site session including whiteboarding and hands-on activities. • Leadership chats with our Head of People, Head of Engineering and CEO. • We care deeply about the warm, inclusive environment we’re building at Tessl and we value diversity – we welcome applications from those typically underrepresented in tech. If you like the sound of this role but are not totally sure whether you’re the right person, do apply anyway! • LEARN HOW WE THINK AND WORK • On Tessl, The AI Native Development Startup https://www.tessl.io/blog/announcing-tessl-the-ai-native-development-startup • Announcing skills on Tessl: the package manager for agent skills https://tessl.io/blog/skills-are-software-and-they-need-a-lifecycle-introducing-skills-on-tessl/ • Podcast Episode: The End of Fragmented Agent Context, Guy Podjarny Tessl CEO https://youtu.be/ntkM-hRblfo
Apply in one click
Upload My Resume
Drop here or click to browse · Tap to choose · PDF, DOCX, DOC, RTF, TXT