Software Engineer, Tokens and Prompt Structures

<div class="content-intro"><h2><strong>About Anthropic</strong></h2> <p>Anthropic’s mission is to create reliable, interpretable, and steerable AI systems. We want AI to be safe and beneficial for our users and for society as a whole. Our team is a quickly growing group of committed researchers, engineers, policy experts, and business leaders working together to build beneficial AI systems.</p></div><h2><strong>About the Role:</strong></h2> <p>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 tool results, and so on.</p> <p>As a Software Engineer on this team, you'll own the design and maintenance of these libraries—keeping their APIs intuitive, their performance sharp, and their abstractions solid enough that most of the org never has to think about encodings or prompt structures at all. You’ll have the satisfaction of knowing that your work enabled Claude to learn new ways of understanding the world.</p> <p>This role is unusually broad: your work will touch systems across the codebase, from pretraining to finetuning to the API, and you'll collaborate closely with both researchers and engineers to make sure new encoding ideas can move quickly from experiment to production.</p> <h2><strong>Responsibilities:</strong></h2> <ul> <li> <p>Maintain and improve the encoding libraries used by engineers and researchers across Anthropic</p> </li> <li> <p>Run experiments to determine the optimal way to feed structured data into Claude without confusing it</p> </li> <li> <p>Design data structures and abstractions that shield most of the organization from the details of how encoded data works while enabling “power users”</p> </li> <li> <p>Adapt the encoding libraries to support new research directions as they emerge, and make sure that