Applied AI Engineer

The role

You will build an agent environment and agent harness. This involves writing production software in Python, TypeScript, or Rust to manage context, orchestrate workflows, and build tool interfaces.

What you will do

• Build agent harnesses and execution loops.
• Manage context including retrieval and summarization.
• Orchestrate workflows combining model calls with application code and human review.
• Build tool interfaces and validate arguments.
• Build controls for users to inspect progress and intervene.
• Handle failures and control access through retries and permissions.
• Evaluate changes using test cases and performance metrics.
• Operate the system by keeping traces and versioning prompts and code.

Required qualifications

• At least four years building and maintaining production software.
• Hands-on work on an LLM application that calls tools or performs multi-step tasks.
• Strong production experience in at least one of Python, TypeScript, or Rust.
• Experience writing or substantially changing an agent's execution loop.
• Experience with retrieval, context assembly, summarization, or memory for an LLM application.
• Understanding of timeouts, retries, concurrency, and idempotency.
• Experience building tests for model-driven workflows and using execution traces.
• Understanding of prompt injection and security risks.
• Ability to restrict tool access, protect credentials, and implement validation and approval steps.

Nice to have

• Experience with long-running or multi-agent workflows, including checkpoint recovery, task delegation, and shared state.
• Experience building retrieval or memory systems with source tracking, freshness checks, and access controls.
• Experience running controlled comparisons or ablation studies.
• Experience with self-hosted inference, inference optimization, or task-specific fine-tuning.

Benefits

• Medical, dental, and vision plan options.
• Life / AD&D, disability coverage options.
• Paid parental leave: 12 weeks for birthing parents, 4 weeks for non-birthing parents, 6 weeks for adoptive, foster, or intended parents.
• Paid holidays and flexible PTO.
• 401(k) with pre-tax and Roth options.
• HSA/FSA options.
• Dependent care FSA.

Before you apply

• Role is limited to U.S. citizens.
• Some positions may require eligibility to obtain and maintain a U.S. Government security clearance.

About the company

Twenty Technologies industrializes offensive cyber operations for the U.S. and its allies. Headquartered in Arlington, Virginia, the company was founded in 2024.