When to Choose ReAct vs Plan-and-Execute vs Multi-Agent

A single ReAct agent with a small tool allowlist, max turns, timeout, and a clear done condition - unless the workflow is already a fixed checklist, in which case use a template plan.

When specialists need different tools, prompts, models, or trust levels, or when human gates must sit between stages. Same tools with different names is not enough.

Yes if you kept tools, state, and stop policies modular. Many teams start ReAct, then wrap a planner or router around the same tools.

It can reduce reasoning errors inside a pattern, but it does not remove the need for bounds, privilege separation, or plans on long structured jobs.

If steps are clean and tools are reliable, pure plan/execute is enough. If each step needs exploratory tool use, budget a small ReAct loop per step.

Turn count, tool repeat rate, cost per successful task, handoff failure rate, and % stops that are max-turns versus goal-complete.

Not always. Look for real role prompts, tool allowlists, and handoff contracts - not only multiple character names in one prompt.

When inputs and outputs are deterministic, tools are fixed, and branching fits ordinary code. Agents earn their keep under ambiguity or multi-step tool choice.

If the orchestrator cannot explain each role's unique tools and success contract in one sentence, you have too many. Start with two and split only on pain.

Everywhere. Every pattern needs global budgets; multi-agent also needs per-specialist budgets and handoff depth caps.

Name the top-level pattern, draw the loop or graph, list tools per node, list stop conditions, and state why simpler patterns were rejected.

Often no. Research leans ReAct or hybrid; productized business flows lean template plans with narrow tools and stage gates.