dev-docs/architecture/multi-agent.md
This guide shows how to use multiple agents in CopilotKit — from basic routing to agent-specific tools and shared context.
sequenceDiagram
participant React as React App
participant Core as CopilotKitCore
participant Runtime as CopilotRuntime
participant Research as Research Agent
participant Coding as Coding Agent
Note over React: On mount
Core->>Runtime: GET /info
Runtime-->>Core: agents: [{ id: "research" }, { id: "coding" }]
Core->>Core: Create ProxiedAgent for each
Note over React: User picks "research"
React->>Core: useAgent({ agentId: "research" })
Core-->>React: ProxiedAgent(research)
Note over React: User sends message
React->>Core: runAgent({ agent: researchAgent })
Core->>Runtime: POST /agent/research/run
Runtime->>Research: runner.run()
Research-->>React: SSE events
Note over React: User switches to "coding"
React->>Core: useAgent({ agentId: "coding" })
Core-->>React: ProxiedAgent(coding)
React->>Core: runAgent({ agent: codingAgent })
Core->>Runtime: POST /agent/coding/run
Runtime->>Coding: runner.run()
Coding-->>React: SSE events
import { CopilotRuntime } from "@copilotkit/runtime";
import { createCopilotEndpointExpress } from "@copilotkit/runtime/express";
const runtime = new CopilotRuntime({
agents: {
// Each key is the agent ID
default: generalAgent, // Fallback agent
research: researchAgent, // Specialist for research
coding: codingAgent, // Specialist for code
writing: writingAgent, // Specialist for content
},
});
app.use("/api/copilotkit", createCopilotEndpointExpress({ runtime }));
The runtime exposes each agent at its own endpoint:
| Agent ID | Run Endpoint |
|---|---|
default | POST /agent/default/run |
research | POST /agent/research/run |
coding | POST /agent/coding/run |
writing | POST /agent/writing/run |
graph LR
subgraph "Runtime Agent Map"
M["agents: {
default: Agent,
research: Agent,
coding: Agent
}"]
end
subgraph Endpoints
E1["POST /agent/default/run"]
E2["POST /agent/research/run"]
E3["POST /agent/coding/run"]
end
subgraph Agent Instances
A1["General Agent"]
A2["Research Agent"]
A3["Coding Agent"]
end
E1 -->|"agents['default']"| A1
E2 -->|"agents['research']"| A2
E3 -->|"agents['coding']"| A3
import { useAgent } from "@copilotkit/react-core";
function ResearchPanel() {
// Gets the "research" agent
const { agent } = useAgent({ agentId: "research" });
const sendMessage = async (text: string) => {
agent.addMessage({ id: crypto.randomUUID(), role: "user", content: text });
await copilotKit.runAgent({ agent });
};
return <div></div>;
}
function CodingPanel() {
// Gets the "coding" agent
const { agent } = useAgent({ agentId: "coding" });
// ...
}
import { CopilotChat } from "@copilotkit/react-core";
function App() {
return (
<CopilotKitProvider runtimeUrl="/api/copilotkit">
<div style={{ display: "flex" }}>
<CopilotChat agentId="research" threadId="research-1" />
<CopilotChat agentId="coding" threadId="coding-1" />
</div>
</CopilotKitProvider>
);
}
@Component({
/* ... */
})
export class MultiAgentComponent {
private copilotKit = inject(CopilotKit);
researchStore = this.copilotKit.getAgentStore("research");
codingStore = this.copilotKit.getAgentStore("coding");
}
const researchAgent = copilotKit.getAgent("research");
const codingAgent = copilotKit.getAgent("coding");
// Each agent has its own messages, state, and thread
await copilotKit.runAgent({ agent: researchAgent });
await copilotKit.runAgent({ agent: codingAgent });
When you don't specify an agentId, CopilotKit uses "default":
// These are equivalent:
useAgent(); // Uses "default"
useAgent({ agentId: "default" }); // Explicit
// Your backend must have a "default" agent:
const runtime = new CopilotRuntime({
agents: {
default: myAgent, // This is required if any component omits agentId
},
});
On mount, the frontend fetches available agents from the runtime:
sequenceDiagram
participant Core as CopilotKitCore
participant Runtime as CopilotRuntime
Core->>Runtime: GET /info
Runtime-->>Core: { agents: { research: { description: "..." }, coding: { description: "..." } } }
Core->>Core: Create ProxiedAgent for each
Core->>Core: Notify subscribers (onAgentsChanged)
You can react to agent changes:
copilotKit.subscribe({
onAgentsChanged: ({ agents }) => {
console.log("Available agents:", Object.keys(agents));
// e.g. ["default", "research", "coding"]
},
});
Tools can be scoped to specific agents:
// This tool is available to ALL agents
useFrontendTool({
name: "getCurrentTime",
handler: async () => new Date().toISOString(),
});
// This tool is ONLY available to the "research" agent
useFrontendTool({
name: "searchPapers",
agentId: "research",
parameters: z.object({ query: z.string() }),
handler: async ({ query }) => await searchPapers(query),
});
// This tool is ONLY available to the "coding" agent
useFrontendTool({
name: "runCode",
agentId: "coding",
parameters: z.object({ code: z.string(), language: z.string() }),
handler: async ({ code, language }) => await executeCode(code, language),
});
graph TB
subgraph "Tool Registry"
GT["getCurrentTime
<i>All agents</i>"]
SP["searchPapers
<i>research only</i>"]
RC["runCode
<i>coding only</i>"]
end
subgraph Agents
RA["research agent"]
CA["coding agent"]
end
GT --> RA
GT --> CA
SP --> RA
RC --> CA
Context is shared across all agents by default:
function App() {
// Both research and coding agents can see this
useAgentContext("Current user", { name: "Alice", role: "developer" });
useAgentContext("Current project", {
name: "my-app",
language: "TypeScript",
});
return (
<>
<CopilotChat agentId="research" />
<CopilotChat agentId="coding" />
</>
);
}
graph TB
subgraph "Shared Context"
C1["Current user: Alice"]
C2["Current project: my-app"]
end
subgraph Agents
RA["research agent"]
CA["coding agent"]
end
C1 --> RA
C1 --> CA
C2 --> RA
C2 --> CA
Each agent conversation runs on its own thread:
// These are separate conversations with separate histories
<CopilotChat agentId="research" threadId="research-thread-1" />
<CopilotChat agentId="coding" threadId="coding-thread-1" />
graph LR
subgraph "Thread: research-1"
RM1["User: Find papers on AI"]
RM2["Agent: Here are 5 papers..."]
end
subgraph "Thread: coding-1"
CM1["User: Write a sort function"]
CM2["Agent: Here's a quicksort..."]
end
RM1 --> RM2
CM1 --> CM2
Each thread maintains its own:
import { CopilotRuntime } from "@copilotkit/runtime";
import { createCopilotEndpointExpress } from "@copilotkit/runtime/express";
import { BuiltInAgent } from "@copilotkit/runtime/v2";
const agents = {
default: new BuiltInAgent({
model: "openai/gpt-4o",
systemPrompt: "You are a general assistant.",
}),
research: new BuiltInAgent({
model: "openai/gpt-4o",
systemPrompt:
"You are a research specialist. Search for papers and summarize findings.",
}),
coding: new BuiltInAgent({
model: "openai/gpt-4o",
systemPrompt: "You are a coding expert. Write clean, tested code.",
}),
};
const runtime = new CopilotRuntime({ agents });
app.use("/api/copilotkit", createCopilotEndpointExpress({ runtime }));
import {
CopilotKitProvider,
CopilotChat,
useAgent,
useFrontendTool,
useAgentContext,
} from "@copilotkit/react-core";
import { z } from "zod";
export default function App() {
return (
<CopilotKitProvider runtimeUrl="/api/copilotkit">
<SharedContext />
<div style={{ display: "grid", gridTemplateColumns: "1fr 1fr" }}>
<ResearchPanel />
<CodingPanel />
</div>
</CopilotKitProvider>
);
}
// Shared context — all agents see this
function SharedContext() {
useAgentContext("Current project", {
name: "my-saas-app",
stack: "React + Node.js + PostgreSQL",
description: "A SaaS platform for team collaboration",
});
return null;
}
// Research agent with its own tools
function ResearchPanel() {
useFrontendTool({
name: "saveFindings",
agentId: "research",
description: "Save research findings to the knowledge base",
parameters: z.object({
title: z.string(),
summary: z.string(),
sources: z.array(z.string()),
}),
handler: async ({ title, summary, sources }) => {
await knowledgeBase.save({ title, summary, sources });
return "Saved to knowledge base";
},
});
return (
<div>
<h2>Research Assistant</h2>
<CopilotChat agentId="research" />
</div>
);
}
// Coding agent with its own tools
function CodingPanel() {
useFrontendTool({
name: "createFile",
agentId: "coding",
description: "Create a new file in the project",
parameters: z.object({
path: z.string(),
content: z.string(),
}),
handler: async ({ path, content }) => {
await fileSystem.write(path, content);
return `Created ${path}`;
},
});
return (
<div>
<h2>Coding Assistant</h2>
<CopilotChat agentId="coding" />
</div>
);
}