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Pick the engine for the job

When you build an agent in Copilot Studio, one choice shapes everything else: which harness powers it. A harness is the engine underneath your agent — it decides how the agent reasons, what it can touch, where you can publish it, and how it bills. Same builder, different engines, and the right one depends on the job.

Unofficial — confirm before you commit

This is community guidance, not a Microsoft prescription. Harness capabilities, packaging, and billing evolve quickly. Use this to start the conversation, then confirm against Licensing & Prerequisites and Microsoft's Copilot Studio documentation.

Where it's heading — and the honest tradeoff

Microsoft is investing most in the GitHub Copilot harness, and new agent capability tends to land there first. Reach for it when the job is a complex, multi-step process a rules script can't handle gracefully: it reasons through the whole goal on its own, retries and finds another path when a step fails, works directly across Word, Excel, PowerPoint, and PDF files, and carries context with skills and memory. That capability is why it's the engine to grow into. Weigh two facts with equal honesty: it is the only harness a Microsoft 365 Copilot license does not cover, and it bills Copilot Credits for all usage — creation and runtime. The standard and chat harnesses are covered by a Microsoft 365 Copilot license inside Microsoft 365 channels and cost less for predictable, rules-based work. Pick for the job and the budget — the Credit Estimator models the real net cost of each.

Pick the engine for the job

Every harness reasons, publishes, and bills differently. Click any card to see how it works and where it shines — or jump to the side-by-side.

Side by side

The same considerations, compared across all three harnesses. Find the row that matters most to your job.

Considerations GitHub Copilot harness Standard harness Copilot chat harness
Best for Complex, multi-step business processes Rule-based agents and structured conversations Extending M365 Copilot Chat with enterprise knowledge
How it works Reasons through a goal on its own, step by step Follows the topics and rules you define Connects enterprise knowledge to M365 Copilot Chat
Recovers from problems Retries and finds alternative paths automatically Follows the paths you've built Not a focus
Works with files Creates, edits, and reasons over Word, Excel, PowerPoint, and PDF files Not a focus Not a focus
Skills and memory Yes Not a focus Not a focus
Publishing Internal teams or external customers Internal teams or external customers Internal teams
Covered by your M365 Copilot license? No — credits for all usage Yes — inside M365 channels Yes — included in M365 Copilot USLs
Billing Copilot Credits See Copilot Studio licensing Consumption, or included in M365 Copilot USLs

Two things to take away

  1. The harness is a capability choice, not just a setting. Autonomy, file-handling, and where you can publish are all downstream of which engine you pick — so choose for the job, not the default.
  2. They bill — and are covered — differently. Copilot Credits, Copilot Studio licensing, and M365 Copilot USLs are not the same meter, and only the standard and chat harnesses are covered by a Microsoft 365 Copilot license (in M365 channels) — the GitHub Copilot harness never is. Sort out cost and coverage before you scale, not after — see Licensing & Prerequisites and the Credit Estimator.

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