Two Legitimate Paths, Not a Hierarchy
It's tempting to think of Copilot Studio as the 'starter' product and Azure AI Foundry as the 'real' enterprise platform, but that framing causes bad decisions. Copilot Studio is a mature, governed, low-code platform purpose-built for conversational agents that plug into Microsoft 365, Dynamics 365, and Power Platform data — it is the correct choice for a large share of enterprise use cases, not a stepping stone away from them.
Azure AI Foundry's Agent Service, by contrast, is the code-first platform for building custom agents with fine-grained control over model selection, orchestration logic, tool-calling, and infrastructure (networking, identity, observability). The two products share underlying model access (both can call Azure OpenAI-hosted models) and increasingly interoperate — Copilot Studio agents can call out to custom Azure AI Foundry-hosted skills, and Foundry agents can be surfaced inside Teams or Copilot experiences — but they are built for different engineering teams and different governance postures.
The practical question isn't 'which is more powerful' but 'which fits the skill set of the team that will maintain this for the next three years, and does the use case need capabilities only available in one of the two.' Get this wrong and you either pay a 'low-code tax' (fighting Copilot Studio's constraints for a use case that needed custom orchestration) or a 'custom-build tax' (maintaining bespoke infrastructure for a conversational FAQ bot that Copilot Studio would have shipped in two weeks).