Founding Engineer, AI Agent Systems (Equity)

Cross Border Talents; Watford; On-site; GBP 130,000 - 170,000; Full time

Benefits offered by this job

EMI-eligible equity

Roof terrace on King's Cross office

On-site facilities

Job summary

Cross Border Talents is seeking a Founding Engineer for Agent Systems in London. You will own the core agent orchestration platform and design multi-step workflows, building secure, production-grade AI features in a seed-stage startup with seven-figure revenue. On-site-first role with impressive equity and market compensation.

You will shape AI reliability, evaluation, and tool-calling capabilities, operating with founding-team ownership and high autonomy in a fast-moving environment.

Qualifications

• Strong professional backend engineering experience.
• 1–2+ years of experience shipping production LLM-powered features
• Experience with tool calling and multi-step orchestration
• Experience with dataset curation and regression testing
• Understanding of LLM-as-judge approaches and failure modes
• Strong systems-thinking ability

Responsibilities

• Build and evolve the core agent orchestration platform.
• Design multi-step agent workflows and tool-calling systems
• Build context-management and agent-scaffolding infrastructure
• Develop secure sandboxing for agent execution
• Implement prompt-injection defenses and other agent-security controls
• Build production evaluation frameworks for high-stakes outputs
• Own AI reliability and ship/no-ship decisions when necessary

Skills

Backend engineering

Production LLM features

TypeScript/Node.js

Agent frameworks

API security

Asynchronous systems

Reliability patterns

Product ownership

Tools

TypeScript

Node.js

React

Tailwind

Express

Azure

Postgres

Terraform

GitHub Actions

Docker

Anthropic APIs

Claude Code

Job description

Cross Border Talents is seeking a Founding Engineer for Agent Systems in London. You will own the core agent orchestration platform and design multi-step workflows, building secure, production-grade AI features in a seed-stage startup with seven-figure revenue. On-site-first role with impressive equity and market compensation.

You will shape AI reliability, evaluation, and tool-calling capabilities, operating with founding-team ownership and high autonomy in a fast-moving environment.