Software Engineer, Tokens and Prompt Structures

Job summary

Responsibilities

The Encodings Infra team maintains the libraries that engineers and researchers across Anthropic use to encode text and multimodal data into a form that Claude can consume. It also determines Claude’s prompt shape: how a user’s turn is represented to the model, how Claude calls tools and receives…

• Maintain and improve the encoding libraries used by engineers and researchers across Anthropic
• Run experiments to determine the optimal way to feed structured data into Claude without confusing it
• Design data structures and abstractions that shield most of the organization from the details of how encoded data works while enabling “power users”
• Adapt the encoding libraries to support new research directions as they emerge, and make sure that we can ship these research ideas to production
• Optimize encoding performance across the systems that depend on these libraries

What they're looking for

• Tokenizers or other text/data encoding systems
• Maintaining a widely-used library over a long period of time
• Performance optimization
• Python and/or Rust
• Reinforcement learning or model training infrastructure

Tech stack

• Python
• Rust