Codex Multi-Agents v2: Sol Delegates Grunt Work to Cheaper Luna
OpenAI shipped cross-model delegation in Codex on August 15, 2026, announced by Eric Provencher on X: an orchestrator agent named Sol can now delegate narrowly-defined tasks to Luna, the fastest and lowest-cost model in the GPT-5.6 family. Luna is a pure sub agent — it cannot message or spawn other agents — and routing still requires prompting, with same-model delegation as the default. Provencher advises capping sub-agent counts around 6-8, a lesson underscored by July 22, 2026 GitHub issues where Luna was rejected as an unknown model and spawn-schema changes broke workflows.