GitHub Copilot SDK

Overview

The GitHub Copilot SDK is a multi-platform agent runtime that embeds Copilot's agentic workflows into applications. It exposes the same engine behind Copilot CLI, enabling programmatic invocation without requiring custom orchestration development.

Status: Technical Preview (suitable for development and testing)

Supported Languages: TypeScript/Node.js, Python, Go, .NET

Primary Documentation

Language-Specific SDK Docs

CLI and Configuration Docs

Prerequisites

GitHub Copilot Subscription - Pro, Pro+, Business, or Enterprise
GitHub Copilot CLI - Installed and authenticated (copilot --version)
Runtime: Node.js 18+, Python 3.8+, Go 1.21+, or .NET 8.0+

Installation

Language	Command
TypeScript/Node.js	`npm install @github/copilot-sdk`
Python	`pip install github-copilot-sdk`
Go	`go get github.com/github/copilot-sdk/go`
.NET	`dotnet add package GitHub.Copilot.SDK`

Architecture

Application → SDK Client → JSON-RPC → Copilot CLI (server mode)

The SDK manages CLI lifecycle automatically. External server connections supported via cliUrl / cli_url.

Quick Start (TypeScript)

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

const client = new CopilotClient();
await client.start();

const session = await client.createSession({ model: "gpt-5" });

// Register handler BEFORE send()
session.on((event) => {
  if (event.type === "assistant.message") {
    console.log(event.data.content);
  }
});

await session.send({ prompt: "What is 2 + 2?" });

await session.destroy();
await client.stop();

Critical: Register event handlers before calling send() to capture all events.

For complete examples in all languages, see references/working-examples.md.

Core Concepts

Client

Main entry point. Manages CLI server lifecycle and session creation.

Operations: start(), stop(), createSession(), resumeSession()

Config: cliPath, cliUrl, port, useStdio, autoStart, autoRestart

Session

Individual conversation context with message history.

Operations: send(), sendAndWait(), on(), abort(), getMessages(), destroy()

Config: model, streaming, tools, systemMessage

Events

Key events during processing:

Event	Purpose
`assistant.message`	Complete response
`assistant.message_delta`	Streaming chunk
`session.idle`	Ready for next prompt
`tool.execution_start/end`	Tool invocations

For full event lifecycle and SessionEvent structure, see references/event-system.md.

Streaming

streaming: false (default) - Content arrives all at once
streaming: true - Content arrives incrementally via assistant.message_delta

Final assistant.message always fires regardless of streaming setting.

Available Models

See Supported AI Models for full list.

Provider	Model ID	Notes
OpenAI	`gpt-4.1`, `gpt-5`, `gpt-5-mini`	Included
OpenAI	`gpt-5.1`, `gpt-5.1-codex`, `gpt-5.2`	Premium
Anthropic	`claude-sonnet-4.5`	Premium (CLI default)
Anthropic	`claude-opus-4.5`	Premium (3× multiplier)
Google	`gemini-3-pro-preview`	Premium

Custom Tools

TypeScript (Zod):

const tool = defineTool("lookup_issue", {
  description: "Fetch issue details",
  parameters: z.object({ id: z.string() }),
  handler: async ({ id }) => fetchIssue(id),
});

Python (Pydantic):

@define_tool(description="Fetch issue details")
async def lookup_issue(params: IssueParams) -> dict:
    return fetch_issue(params.id)

For complete tool examples in all languages, see references/working-examples.md.

Language Conventions

Concept	TypeScript	Python	Go	.NET
Create session	`createSession()`	`create_session()`	`CreateSession()`	`CreateSessionAsync()`
Delta content	`deltaContent`	`delta_content`	`DeltaContent`	`DeltaContent`

For full conventions table, see references/event-system.md.

CLI Configuration

Config stored in ~/.copilot/:

config.json - General configuration
mcp-config.json - MCP server definitions

For custom agents and MCP setup, see references/cli-agents-mcp.md.

Troubleshooting

Problem	Solution
Events fire but content empty	Use `event.data.content`, not `event.content`
Handler never fires	Register before `send()`
Python enum issues	Use `event.type.value`
Go nil pointer	Check `!= nil` before dereferencing

For debugging techniques, see references/troubleshooting.md.

Skill References

Detailed documentation in this skill:

references/working-examples.md - Complete examples for all languages, custom tools
references/event-system.md - Event lifecycle, SessionEvent structure, language conventions
references/troubleshooting.md - Common issues, debugging techniques
references/cli-agents-mcp.md - CLI configuration, custom agents, MCP server setup

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