Developer Dan McInerney released architect-loop, a Claude Code skill that creates a cross-vendor AI agent loop using existing subscriptions instead of API keys. The system pairs Claude Fable as architect with GPT-5.5 Codex as builder, enabling parallel development without additional token costs.

The architect role handles design, specification, and judgment while the builder executes engineering tasks. Work blocks split into isolated lanes using git worktrees, with frozen acceptance gates that automatically fail if modified by builders. This separation prevents weak planning from undermining execution quality.

For research workflows, the system employs a scout-first approach where Codex maps topics before Fable designs specialized lanes. Parallel researchers operate under strict budgets with source verification requirements—findings must include URLs, dates, and confidence tags rather than inference.

The repository serves as persistent memory through handoff documents and gate files. Liveness checks monitor dispatched runs while built-in supervision handles timeouts and stall triage. Available under the MIT license, it installs in 30 seconds via npm and git clone.