Key skills
AI
About this role
Tessl is a fast-growing Series A startup based in London, focused on building the context layer for AI coding agents and a platform for AI-native software development. They are seeking a Research Engineer to join their AI Research team, where you will work on components that enhance agent harnesses, evaluate model behavior, and improve workflows through substantial experiments.
Responsibilities:
- 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