By Sagar Shankaran, Founder of CallSphere
Copilot Studio's 2026 multi-agent orchestration is GA in April. Here is how a CallSphere voice agent connects to Teams agents, fine-tuned models, and the Prompt Builder via Power Platform connectors.
Key takeaways
Copilot Studio's multi-agent orchestration went GA in April 2026 and the Copilot Studio for Teams app stops accepting new classic chatbots after June 2026. Voice agents that integrate now ride the new platform; teams that wait will migrate twice.
flowchart LR
User --> Triage["Triage / Supervisor"]
Triage -->|tool A| A["Specialist A"]
Triage -->|tool B| B["Specialist B"]
Triage -->|tool C| C["Specialist C"]
A --> Mem[(Shared memory · mem0/Letta)]
B --> Mem
C --> Mem
Mem --> Final["Final response"]A CallSphere voice agent on a B2B sales call hits a question only the SE knows. Instead of guessing or sending an email, the voice agent invokes the company's "Solutions Engineering Copilot" — a Teams-resident agent in Copilot Studio fine-tuned on the technical docs. The Teams agent answers in 1.4 seconds, the voice agent relays it to the caller, and the entire exchange is logged to Dataverse for sales-ops review. Multi-agent orchestration plus 365 Copilot Tuning means your voice agent inherits expertise from every internal Copilot you have already built.
Three integration paths. Direct Line API (https://directline.botframework.com/v3/directline) gives you a programmatic conversation channel into any Copilot Studio agent. Power Automate connectors let CallSphere trigger flows that invoke Copilot agents and return structured results. Copilot Studio MCP (Public Preview Q1 2026) exposes Copilot agents as MCP tools — promise check the What's New page since toolset GA dates shift.
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Auth is Entra ID OAuth 2.0 with the https://api.botframework.com/.default scope for Direct Line, plus Dataverse.User if you read tables, and Sites.Read.All for SharePoint-grounded agents.
CallSphere's Sales product treats Copilot Studio agents as escalation peers. When a Sales voice agent does not have an answer, it round-trips to the customer's "Sales Engineering Copilot" via Direct Line and gets a 200-400 token response in 1-2 seconds. CallSphere's IT Helpdesk vertical does the same for "Internal Operations Copilot." Healthcare's Patient Care agent reaches into "Clinical Knowledge Copilot" tuned on the practice's internal protocols. All round-trips emit Audit logs to Microsoft Purview so compliance teams retain visibility.
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POST /v3/directline/conversations to start, POST /v3/directline/conversations/{id}/activities to send the user question, then poll GET /v3/directline/conversations/{id}/activities?watermark= until the bot replies (typically 1-3s).// Start a Copilot Studio Direct Line conversation from CallSphere mid-call
const conv = await fetch("https://directline.botframework.com/v3/directline/conversations", {
method: "POST",
headers: {
Authorization: `Bearer ${directLineSecret}`,
"Content-Type": "application/json",
},
});
const { conversationId, token } = await conv.json();
await fetch(
`https://directline.botframework.com/v3/directline/conversations/${conversationId}/activities`,
{
method: "POST",
headers: { Authorization: `Bearer ${token}`, "Content-Type": "application/json" },
body: JSON.stringify({
type: "message",
from: { id: `callsphere-${turn.callId}` },
text: extracted.customerQuestion,
}),
}
);
Do we need Copilot Studio licenses for this? Yes. Copilot Studio is licensed via Microsoft 365 Copilot or as a standalone SKU. Direct Line is included; per-message limits apply.
Still reading? Stop comparing — try CallSphere live.
CallSphere ships complete AI voice agents per industry — 14 tools for healthcare, 10 agents for real estate, 4 specialists for salons. See how it actually handles a call before you book a demo.
Is the new Prompt Builder relevant to my voice agent? Indirectly — it speeds up updates to the Copilot Studio agents you delegate to. Faster Copilot iteration means faster voice agent iteration.
What about the June 2026 cutoff? Existing classic Teams chatbots keep working but no new ones. If you are starting now, build directly in Copilot Studio web.
How does Microsoft Purview audit fit in? Every Direct Line call is auditable. Add CallSphere call IDs to the activity channelData so cross-system tracing works.
How do I try this? Start a trial and reach out via demo for a Teams + Copilot Studio walkthrough.
Written by
Sagar Shankaran· Founder, CallSphere
Sagar Shankaran is the founder of CallSphere, where he builds production AI voice and chat agents deployed across healthcare, hospitality, real estate, and home services. He writes about agentic AI, LLM engineering, and shipping voice agents that handle real calls in production.
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