Agent Runtime & Systems - Member of Technical Staff

About the role

Callosum is building a software orchestration layer to unify heterogeneous compute for AI systems. This role owns the runtime and programming model for long-running agent systems, focusing on durable execution, distributed scheduling, and observability. You will develop core software to make agent workflows reliable, debuggable, and efficient across a full-stack infrastructure.

Responsibilities

• Design and build stateful, asynchronous agent runtimes across distributed environments
• Define event histories, checkpoint and resume semantics, and recovery from partial failure
• Build traces, replay, time-travel debugging, and hierarchical tracing across model calls and tools
• Develop clear Python APIs, libraries, and DSLs with stable extension points
• Design scheduling, placement, backpressure, resource accounting, and sandboxing for secure tool execution
• Develop tooling for trajectory collection, performance profiling, and failure attribution

Required skills

• Distributed systems
• Python
• Rust
• C++
• Go
• Durable workflows
• Actor systems
• Workflow engines
• API design

Nice to have

• Ray
• Temporal
• Kafka
• Erlang
• BEAM
• PyTorch
• JAX
• TensorFlow
• ML systems

Benefits

• Competitive Salary
• Equity
• Private healthcare
• Visa sponsorship
• Relocation benefits

About the Company

Callosum is the Intelligent Systems Company building infrastructure that unifies heterogeneous compute across the full stack. They are focused on co-evolving models, workflows, and silicon to deliver inference tailored to every workload.