Build a local coding harness around existing tools with Codex
After reading our How I AI episode about Mozilla’s agent workflow, I asked Codex what a similar setup could look like for ChatPRD. The discussion moved toward a local coding harness: an application that gives a coding agent a defined task, the relevant tools, and a place to save its work. I also used Factory’s CLI as a reference while thinking through the interface.
Codex inspected the skills and command-line tools we already used, then built a terminal interface around a Claude Agent SDK worker. The harness could assemble a task brief, run readiness checks, collect available evidence, and save the worker prompt and outputs together. Investigation and code-editing modes had different permissions. I wanted the setup for a task to be repeatable, including which tools the agent should reach for first.
This got to a local implementation with checks and a browsable record of runs. Some integrations still needed configuration. The useful experiment was packaging our existing development workflow so I would not have to explain the same tools, context, and expectations at the start of every task.