Applied AI Engineer, Agent Harness

Apple’s Siri organization is seeking an Applied AI Engineer to develop the Agent Harness that enables large language models to operate as assistants. The role emphasizes agent runtime engineering, eval-driven iteration, and low-latency, privacy-forward assistant behavior across on-device and server models.

Key Responsibilities

• Design and evolve core components of the agent runtime, including the planning loop, session lifecycle, concurrency, and cancellation
• Develop the transcript and conversation state, along with the platform that defines tools and dynamic instructions and delivers them to the model
• Build an executor that dispatches tool calls into Apple apps and services, and manages results and failures reliably
• Integrate on-device and server models with low-latency streaming, including interruption mid-response
• Embed safety, security, and privacy protections into harness components in collaboration with security and privacy partners
• Validate harness changes using evals and latency metrics, adapting the harness as new model generations arrive
• Create tracing, replay, and testing tools to make a nondeterministic system debuggable

Required Qualifications

• Bachelor's degree in Computer Science or a related field, with 2+ years of industry experience
• Strong programming skills in a systems language such as Swift, C++, Rust, Objective-C, or Go
• Solid foundation in concurrency, inter-process communication, and performance optimization
• Hands-on experience building LLM-powered systems such as agents, tool calling, or prompt and context design through professional work or substantial personal projects
• Daily use of agentic coding tools such as Claude Code, Codex, or Pi, with informed opinions on what makes their harnesses succeed or fail
• Ability to communicate clearly and make progress on ambiguous problems

Technologies

• Swift, C++, Rust, Objective-C, Go
• Claude Code, Codex, Pi

Preferred Qualifications

• Experience with Swift and Apple platform development
• Experience building agent harnesses, orchestration frameworks, or multi-step tool-use systems
• Experience with model inference integration, streaming protocols, or latency-sensitive client-server systems
• Experience using evals to diagnose and improve LLM behavior
• Experience designing APIs or platforms adopted by other engineering teams
• Familiarity with privacy and security engineering in production systems
• Active engagement with current research and practice in agent harness design, including context engineering, tool use, and long-horizon agents, with a record of turning new ideas into practical improvements

Compensation and Location

• Location: Cupertino, CA (onsite)
• Salary: USD 150,400 - 225,300 per year

Benefits

• Comprehensive medical and dental coverage
• Retirement benefits
• A range of discounted products and free services
• Reimbursement for certain educational expenses, including tuition
• Opportunity to become an Apple shareholder through participation in Apple’s discretionary employee stock programs
• Eligibility for discretionary restricted stock unit awards
• Option to purchase Apple stock at a discount through participation in the Employee Stock Purchase Plan
• Discretionary bonuses or commission payments may apply, and relocation may be available

Education

Bachelor's degree in Computer Science or a related field.