Thanks for the follow-up — a couple of clarifications that usually explain what you’re seeing.
1) “It worked for months, now it doesn’t” (why it can look like a new issue)
In Copilot Studio / Power Platform, AI capabilities (including prompts / AI tools) are tied to specific runtime/billing surfaces. If you recently changed the flow plan to “Copilot Studio”, the way AI usage is metered and/or the eligibility rules for certain AI features can change as the product evolves (especially for preview features). Copilot Studio and AI tools are billed/managed through Copilot Credits, and the platform has been actively updating these rules since the shift to Copilot Credits. See Copilot Studio licensing and billing details.
2) If prompts can only be used with “When an agent calls the flow”, what’s the alternative for other triggers?
If your scenario starts from other triggers (SharePoint/Dataverse/Recurrence/etc.), the recommended alternative is:
- Keep your flow with the required trigger (SharePoint/Dataverse/Recurrence).
- Use AI via AI tools in Power Automate (prompt/model actions) where supported, OR
- Call a Copilot Studio agent from the flow (so the agent does the reasoning and returns structured output), then continue the automation.
Separately, Copilot Studio also supports event-triggered agent execution (agents acting autonomously on external events), which is designed for “non user-typed” triggers.
So you typically have two robust patterns:
A) Flow trigger → AI tool/prompt action in the flow (if available in your environment/region)
B) Flow trigger → “execute/call agent” → agent uses prompts/knowledge/tools → flow continues with the agent result
3) Which credits are used in these scenarios (if not from the Copilot Studio license)?
Microsoft’s current model is:
- AI tools / prompts in Copilot Studio agents and agent flows consume Copilot Credits.
- In Power Automate / Power Apps, prompt and model capabilities consume Copilot Credits when AI Builder credits aren’t available (or when AI Builder capacity is exceeded).
- For Copilot Studio agents, interactive employee-facing usage by users licensed with Microsoft 365 Copilot is “no charge” from the tenant Copilot Credits pool for the covered agent features (subject to Microsoft’s fair-use limits and the specific scenario).
Practical takeaway:
- If the flow/prompt runs outside an interactive “M365 Copilot licensed user” context (for example, a scheduled flow or a background trigger), it will typically draw from your organization’s Copilot Credits capacity (prepaid or pay-as-you-go), rather than being covered as “no charge” interactive usage.
