omo vs oms: Fallback Chains Deep Dive

This is Part 2 of When Your AI Coding Tool Needs Three Configs. Part 1 covered the config design, file structure, and orchestration philosophy. This article focuses on fallback mechanisms. omo = oh-my-openagent, oms = oh-my-opencode-slim. Model and provider names are anonymized as provider-a/model-x etc. Why Bother Understanding Fallback omo and oms both support fallback—automatic switching to backup when the primary model is unavailable. But their mechanisms differ completely: omo is a multi-layer pipeline that degrades step by step; oms uses startup model selection + runtime abort retry. You need to understand this difference to configure a reliable chain. ...

2026-06-07 · 13 min · Alex Wang

When Your AI Coding Tool Needs Three Configs

Why I Need Three OpenCode Configs I have three opencode.json files in my ~/.config/opencode/ directory. The reason is simple: I wanted to run oh-my-openagent (omo from here on) and oh-my-opencode-slim (oms from here on) side by side, comparing them to understand where each one’s boundaries lie. omo is the full version—it comes with a batch of built-in agents (Sisyphus, Atlas, Prometheus, Oracle, Explore, Librarian, Metis, Momus, etc.), plus the ones I register on demand. The core is the fallback chain and the Sisyphus orchestrator: throw a refactoring task at Sisyphus, and it breaks the task down for Prometheus to plan, Atlas to execute the plan and distribute subtasks, Explore to search code, Oracle to analyze, then Sisyphus aggregates the results. oms is the slim version—it also has an orchestrator as the main agent responsible for executing tasks, but the difference is in the review phase: oms uses council multi-model consensus, where multiple councillors review results in parallel, and the Council agent synthesizes outputs from all councillors to reach a final conclusion. ...

2026-06-05 · 10 min · Alex Wang