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Multi-Agent Patterns Guide

dev-docs/architecture/multi-agent.md

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Multi-Agent Patterns Guide

This guide shows how to use multiple agents in CopilotKit — from basic routing to agent-specific tools and shared context.


How Multi-Agent Routing Works

mermaid
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

Backend: Register Multiple Agents

typescript
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 IDRun Endpoint
defaultPOST /agent/default/run
researchPOST /agent/research/run
codingPOST /agent/coding/run
writingPOST /agent/writing/run
mermaid
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

Frontend: Select an Agent

React

tsx
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" });
  // ...
}

Using CopilotChat with agent IDs

tsx
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>
  );
}

Angular

typescript
@Component({
  /* ... */
})
export class MultiAgentComponent {
  private copilotKit = inject(CopilotKit);

  researchStore = this.copilotKit.getAgentStore("research");
  codingStore = this.copilotKit.getAgentStore("coding");
}

Vanilla JS

typescript
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 });

The DEFAULT_AGENT_ID

When you don't specify an agentId, CopilotKit uses "default":

typescript
// 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
  },
});

Agent Discovery

On mount, the frontend fetches available agents from the runtime:

mermaid
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:

typescript
copilotKit.subscribe({
  onAgentsChanged: ({ agents }) => {
    console.log("Available agents:", Object.keys(agents));
    // e.g. ["default", "research", "coding"]
  },
});

Agent-Specific Tools

Tools can be scoped to specific agents:

tsx
// 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),
});
mermaid
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

Shared Context

Context is shared across all agents by default:

tsx
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" />
    </>
  );
}
mermaid
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

Thread Isolation

Each agent conversation runs on its own thread:

tsx
// These are separate conversations with separate histories
<CopilotChat agentId="research" threadId="research-thread-1" />
<CopilotChat agentId="coding" threadId="coding-thread-1" />
mermaid
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:

  • Message history
  • Agent state
  • Running status

Full Example: Multi-Agent Dashboard

Backend

typescript
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 }));

Frontend (React)

tsx
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>
  );
}