Research Engineer (Harness Engineering and Agentic Orchestration)
TesslAI-native Software company
London, United KingdomSenior
Index Ventures
Accel
GV
boldstart
Data & AI
About the role
TL;DR
Research Engineer to join AI Research team, focusing on agent harnesses and orchestration.
- •We're hiring a Research Engineer to join our AI Research team.
- •You'll work on components that make the outer loop real: how agent harnesses orchestrate model behavior, how we evaluate what's actually working, how pipelines turn production traces into the next round of improvement, and how we diagnose the failure modes that matter to real users.
- •Key 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.
- •Requirements 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.
Required skills
LLMsPythonPandasNumPyTensorFlowPyTorchAirflowKubernetesCI/CDDockerGitHub ActionsGitJenkinsPrometheusGrafana
Nice-to-have skills
A/B TestingRoadmappingDesign ThinkingPrototypingProgram ManagementProject ManagementCustomer SuccessCustomer OnboardingImplementation Management
Domain expertise
ai
Benefits & perks
Health insurance, Pension contributions
Tech stack
LLMsPythonPandasNumPyTensorFlowPyTorchAirflowKubernetesCI/CDDockerGitHub ActionsGitJenkinsPrometheusGrafanaDatadogNew RelicPagerDutyNginxHAProxyOAuthJWTSAMLOWASPPenetration TestingSOC 2GDPRHIPAAVaultIAM
