Remote C Engineer: Codebase Explorer & AI Trainer

Obsidian; Chicago (IL); On-site; Part time

Benefits offered by this job

Fully remote work

Job summary

Mercor is seeking experienced C engineers to build datasets that train AI agents to reason about real codebases. You will tackle high-level questions across foundational C systems in production codebases, including PostgreSQL, Redis, git, and more.

Tasks are paid per approved task and performed remotely in Mercor Studio. Expect to navigate complex repositories, understand runtime behavior, and iteratively refine questions and rubrics with expert review.

Qualifications

• 3+ years of professional software engineering experience, with substantial production C
• Demonstrated ability to navigate a large, unfamiliar C codebase and explain how it behaves at runtime
• Comfort with preprocessor-heavy builds, platform conditionals, manual memory management, and autotools/CMake/Meson build graphs
• Experience with databases, cryptography, networking protocols, or systems programming is highly relevant
• Ability to use debuggers, sanitizers, tracing, and profilers to establish what the code actually does
• Precise written English: the questions and rubrics you write are the product

Responsibilities

• Select tasks from a pre-validated pool of C repositories, each pinned to a specific git commit and arriving with an engineering question, positive and negative rubrics, foils, and a golden solution
• Explore the repository until you genuinely understand the subsystem in question, including the relevant PR or issue history
• Rewrite the task's question so it defeats frontier coding agents while remaining well-defined and fairly answerable
• Adjust rubrics and foils so they reward correct reasoning and reject plausible-but-wrong answers
• Run the full validation loop in Studio — Check, Golden, Run, Analyze — and iterate until every stage passes
• Document your work in the task README and submit for expert review, addressing reviewer feedback on returned tasks

Skills

C programming

Codebase navigation

Runtime reasoning

Job description

Mercor is seeking experienced C engineers to build datasets that train AI agents to reason about real codebases. You will tackle high-level questions across foundational C systems in production codebases, including PostgreSQL, Redis, git, and more.

Tasks are paid per approved task and performed remotely in Mercor Studio. Expect to navigate complex repositories, understand runtime behavior, and iteratively refine questions and rubrics with expert review.