Remote C Engineer & Codebase AI Trainer

Mercor; Chicago (IL); On-site; USD 29,000 - 36,000; Full time

Job summary

Mercor is seeking experienced C engineers to build the dataset that teaches AI agents to reason about real codebases. You will select tasks from a pre-validated pool of C repositories, explore runtime behavior, and rewrite questions to challenge frontier agents.

This track covers top-tier codebases like PostgreSQL, Redis, git, and OpenSSH. This is a fully remote, asynchronous role with payment per approved task, modular task access via Mercor Studio, and onboarding requirements including

Qualifications

• 3+ years of professional software engineering experience with substantial production C.
• Ability to navigate a large unfamiliar C codebase and explain runtime behavior.
• 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 relevant.
• Ability to use debuggers, sanitizers, tracing, and profilers to establish code behavior.
• 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.
• Explore the repository until you understand the subsystem and its PR/issue history.
• Rewrite the task's question to defeat frontier coding agents while remaining well-defined.
• Adjust rubrics and foils to reward correct reasoning and reject plausible-but-wrong answers.
• Run the full validation loop in Studio — Check, Golden, Run, Analyze — and iterate.
• Document your work in the task README and address reviewer feedback on returned tasks.

Job description

Mercor is seeking experienced C engineers to build the dataset that teaches AI agents to reason about real codebases. You will select tasks from a pre-validated pool of C repositories, explore runtime behavior, and rewrite questions to challenge frontier agents.

This track covers top-tier codebases like PostgreSQL, Redis, git, and OpenSSH. This is a fully remote, asynchronous role with payment per approved task, modular task access via Mercor Studio, and onboarding requirements including