Your App → SDK Client → [stdio/TCP] → Copilot CLI → Model Provider
                                          ↕
                                     MCP Servers

import { CopilotClient } from "@github/copilot-sdk";

const client = new CopilotClient();
const session = await client.createSession({ model: "gpt-4.1" });

const response = await session.sendAndWait({ prompt: "What is 2 + 2?" });
console.log(response?.data.content);

await client.stop();

import asyncio
from copilot import CopilotClient

async def main():
    client = CopilotClient()
    await client.start()
    session = await client.create_session({"model": "gpt-4.1"})
    response = await session.send_and_wait({"prompt": "What is 2 + 2?"})
    print(response.data.content)
    await client.stop()

asyncio.run(main())

client := copilot.NewClient(nil)
if err := client.Start(ctx); err != nil { log.Fatal(err) }
defer client.Stop()

session, _ := client.CreateSession(ctx, &copilot.SessionConfig{Model: "gpt-4.1"})
response, _ := session.SendAndWait(ctx, copilot.MessageOptions{Prompt: "What is 2 + 2?"})
fmt.Println(*response.Data.Content)

await using var client = new CopilotClient();
await using var session = await client.CreateSessionAsync(new SessionConfig { Model = "gpt-4.1" });
var response = await session.SendAndWaitAsync(new MessageOptions { Prompt = "What is 2 + 2?" });
Console.WriteLine(response?.Data.Content);

const session = await client.createSession({ model: "gpt-4.1", streaming: true });

session.on("assistant.message_delta", (event) => {
    process.stdout.write(event.data.deltaContent);
});
session.on("session.idle", () => console.log());

await session.sendAndWait({ prompt: "Tell me a joke" });

from copilot.generated.session_events import SessionEventType

session = await client.create_session({"model": "gpt-4.1", "streaming": True})

def handle_event(event):
    if event.type == SessionEventType.ASSISTANT_MESSAGE_DELTA:
        sys.stdout.write(event.data.delta_content)
        sys.stdout.flush()
    if event.type == SessionEventType.SESSION_IDLE:
        print()

session.on(handle_event)
await session.send_and_wait({"prompt": "Tell me a joke"})

import { CopilotClient, defineTool } from "@github/copilot-sdk";

const getWeather = defineTool("get_weather", {
    description: "Get the current weather for a city",
    parameters: {
        type: "object",
        properties: { city: { type: "string", description: "The city name" } },
        required: ["city"],
    },
    handler: async ({ city }) => ({ city, temperature: "72°F", condition: "sunny" }),
});

const session = await client.createSession({
    model: "gpt-4.1",
    tools: [getWeather],
});

from copilot.tools import define_tool
from pydantic import BaseModel, Field

class GetWeatherParams(BaseModel):
    city: str = Field(description="The city name")

@define_tool(description="Get the current weather for a city")
async def get_weather(params: GetWeatherParams) -> dict:
    return {"city": params.city, "temperature": "72°F", "condition": "sunny"}

session = await client.create_session({"model": "gpt-4.1", "tools": [get_weather]})

type WeatherParams struct {
    City string `json:"city" jsonschema:"The city name"`
}

getWeather := copilot.DefineTool("get_weather", "Get weather for a city",
    func(params WeatherParams, inv copilot.ToolInvocation) (WeatherResult, error) {
        return WeatherResult{City: params.City, Temperature: "72°F"}, nil
    },
)

session, _ := client.CreateSession(ctx, &copilot.SessionConfig{
    Model: "gpt-4.1",
    Tools: []copilot.Tool{getWeather},
})

using Microsoft.Extensions.AI;
using System.ComponentModel;

var getWeather = AIFunctionFactory.Create(
    ([Description("The city name")] string city) => new { city, temperature = "72°F" },
    "get_weather", "Get the current weather for a city");

await using var session = await client.CreateSessionAsync(new SessionConfig {
    Model = "gpt-4.1", Tools = [getWeather],
});

const session = await client.createSession({
    hooks: {
        onPreToolUse: async (input) => {
            if (["shell", "bash"].includes(input.toolName)) {
                return { permissionDecision: "deny", permissionDecisionReason: "Shell access not permitted" };
            }
            return { permissionDecision: "allow" };
        },
    },
});

hooks: {
    onPostToolUse: async (input) => {
        // Redact sensitive data from results
        if (typeof input.toolResult === "string") {
            let redacted = input.toolResult;
            for (const pattern of SENSITIVE_PATTERNS) {
                redacted = redacted.replace(pattern, "[REDACTED]");
            }
            if (redacted !== input.toolResult) {
                return { modifiedResult: redacted };
            }
        }
        return null; // Pass through unchanged
    },
}

hooks: {
    onUserPromptSubmitted: async (input) => {
        return {
            modifiedPrompt: `[User from engineering team] ${input.prompt}`,
            additionalContext: "Follow company coding standards.",
        };
    },
}

hooks: {
    onSessionStart: async (input, invocation) => {
        // input.source: "startup" | "resume" | "new"
        console.log(`Session ${invocation.sessionId} started (${input.source})`);
        return { additionalContext: "Project uses TypeScript and React." };
    },
    onSessionEnd: async (input, invocation) => {
        // input.reason: "complete" | "error" | "abort" | "timeout" | "user_exit"
        await recordMetrics({ sessionId: invocation.sessionId, reason: input.reason });
        return null;
    },
}

hooks: {
    onErrorOccurred: async (input) => {
        // input.errorContext: "model_call" | "tool_execution" | "system" | "user_input"
        // input.recoverable: boolean
        if (input.errorContext === "model_call" && input.error.includes("rate")) {
            return { errorHandling: "retry", retryCount: 3, userNotification: "Rate limited. Retrying..." };
        }
        return null; // Default error handling
    },
}

async def on_pre_tool_use(input_data, invocation):
    if input_data["toolName"] in ["shell", "bash"]:
        return {"permissionDecision": "deny", "permissionDecisionReason": "Not permitted"}
    return {"permissionDecision": "allow"}

session = await client.create_session({
    "hooks": {"on_pre_tool_use": on_pre_tool_use}
})

session, _ := client.CreateSession(ctx, &copilot.SessionConfig{
    Hooks: &copilot.SessionHooks{
        OnPreToolUse: func(input copilot.PreToolUseHookInput, inv copilot.HookInvocation) (*copilot.PreToolUseHookOutput, error) {
            return &copilot.PreToolUseHookOutput{PermissionDecision: "allow"}, nil
        },
    },
})

const session = await client.createSession({
    mcpServers: {
        filesystem: {
            type: "local",
            command: "npx",
            args: ["-y", "@modelcontextprotocol/server-filesystem", "/allowed/path"],
            tools: ["*"],
            env: { DEBUG: "true" },
            cwd: "./servers",
            timeout: 30000,
        },
    },
});

const session = await client.createSession({
    mcpServers: {
        github: {
            type: "http",
            url: "https://api.githubcopilot.com/mcp/",
            headers: { Authorization: "Bearer ${TOKEN}" },
            tools: ["*"],
        },
    },
});

echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' | /path/to/your/mcp-server

npx @modelcontextprotocol/inspector /path/to/your/mcp-server

const client = new CopilotClient({ githubToken: process.env.GITHUB_TOKEN });

const client = new CopilotClient({
    githubToken: userAccessToken,    // gho_ or ghu_ token from OAuth flow
    useLoggedInUser: false,          // Don't use stored CLI credentials
});

const client = new CopilotClient({ useLoggedInUser: false });

provider: { type: "openai", baseUrl: "https://api.openai.com/v1", apiKey: process.env.OPENAI_API_KEY }

provider: {
    type: "openai",
    baseUrl: "https://your-resource.openai.azure.com/openai/v1/",
    apiKey: process.env.FOUNDRY_API_KEY,
    wireApi: "responses",  // Use "responses" for GPT-5 series, "completions" for others
}

provider: {
    type: "azure",
    baseUrl: "https://my-resource.openai.azure.com",  // Just the host — no /openai/v1
    apiKey: process.env.AZURE_OPENAI_KEY,
    azure: { apiVersion: "2024-10-21" },
}

provider: { type: "anthropic", baseUrl: "https://api.anthropic.com", apiKey: process.env.ANTHROPIC_API_KEY }

provider: { type: "openai", baseUrl: "http://localhost:11434/v1" }

from azure.identity import DefaultAzureCredential
from copilot import CopilotClient, ProviderConfig, SessionConfig

credential = DefaultAzureCredential()
token = credential.get_token("https://cognitiveservices.azure.com/.default").token

session = await client.create_session(SessionConfig(
    model="gpt-4.1",
    provider=ProviderConfig(
        type="openai",
        base_url=f"{foundry_url}/openai/v1/",
        bearer_token=token,
        wire_api="responses",
    ),
))

// Create with explicit ID
const session = await client.createSession({
    sessionId: "user-123-task-456",
    model: "gpt-4.1",
});

// Resume later (even from a different client instance)
const resumed = await client.resumeSession("user-123-task-456");
await resumed.sendAndWait({ prompt: "What did we discuss?" });

const sessions = await client.listSessions();           // List all
const lastId = await client.getLastSessionId();          // Get most recent
await client.deleteSession("user-123-task-456");         // Delete from storage
await session.destroy();                                 // Destroy active session

const session = await client.createSession({
    infiniteSessions: {
        enabled: true,
        backgroundCompactionThreshold: 0.80,  // Start background compaction at 80%
        bufferExhaustionThreshold: 0.95,       // Block and compact at 95%
    },
});

const session = await client.createSession({
    customAgents: [{
        name: "pr-reviewer",
        displayName: "PR Reviewer",
        description: "Reviews pull requests for best practices",
        prompt: "You are an expert code reviewer. Focus on security, performance, and maintainability.",
    }],
});

const session = await client.createSession({
    systemMessage: { content: "You are a helpful assistant. Always be concise." },
});

const session = await client.createSession({
    skillDirectories: ["./skills/code-review", "./skills/documentation"],
    disabledSkills: ["experimental-feature"],
});

const session = await client.createSession({
    skillDirectories: ["./skills/security"],
    customAgents: [{ name: "auditor", prompt: "Focus on OWASP Top 10." }],
    mcpServers: { postgres: { type: "local", command: "npx", args: ["-y", "@modelcontextprotocol/server-postgres"], tools: ["*"] } },
});

const session = await client.createSession({
    onPermissionRequest: async (request) => {
        if (request.kind === "shell") {
            return { approved: request.command.startsWith("git") };
        }
        return { approved: true };
    },
    onUserInputRequest: async (request) => {
        return { response: "yes" };
    },
});

session.on("assistant.usage", (event) => {
    console.log("Tokens:", { input: event.data.inputTokens, output: event.data.outputTokens });
});

const client = new CopilotClient({ logLevel: "debug" });

const client = new CopilotClient({ cliArgs: ["--log-dir", "/path/to/logs"] });

console.log("State:", client.getState());  // "connected" after start()
client.on("stateChange", (state) => console.log("Changed to:", state));