Staff Engineer

About the Company

Harper is an AI-native commercial insurance company based in San Francisco. We are rebuilding the trillion-dollar commercial insurance industry from scratch, moving from manual workflows to a system where AI performs the work and humans provide the judgment.

Responsibilities

• Own the agent loop including prompt construction, tool routing, context-window management, and multi-step orchestration.
• Manage the execution environment, including sandbox lifecycle, isolation, and network policy.
• Develop the tool layer, defining schemas, authentication, and observability for agent tools.
• Build model-provider abstraction layers for routing, fallback chains, and cost/latency tradeoffs.
• Design multi-agent coordination patterns and shared-memory contracts.
• Create the harness SDK to enable pod engineers to ship agents faster.
• Implement guardrails for prompt-injection defense, data-egress policy, and PII scrubbing.

Requirements

• 8+ years of software engineering experience, with 3+ years at a Senior+ level in a high-growth company.
• Proven experience building or owning an agent harness at an AI-substrate company.
• Expertise in tool design and understanding the trade-offs between different agent loops.
• Experience shipping sandbox infrastructure at scale (e.g., Firecracker, gVisor).
• Strong written communication skills for RFCs, API contracts, and integration guides.
• Ability to work on-site in San Francisco with high standards and a fast pace.

Preferred Qualifications

• Open-source contributions to agent or harness frameworks.
• Deep expertise in sandbox and isolation technologies.
• Early-access experience with foundation-model providers.