Skip to content

fkucukkara/copilot-sdk-playground

BranchesTags

Repository files navigation

CopilotSDK Playground

A comprehensive demonstration of GitHub Copilot SDK for .NET capabilities, spanning five API projects that cover core chat, RAG (Retrieval-Augmented Generation), MCP tool servers, and multi-agent orchestration — all wired together with .NET 10 and .NET Aspire.

Solution Overview

Project Port Purpose
CopilotSDKPlayground.Api 5100 Core chat API with streaming SSE, tool calling, prompt templates, and Redis memory
CopilotSDKPlayground.RagApi 5200 RAG pipeline: ingest documents → TF-IDF retrieval → grounded Copilot responses
CopilotSDKPlayground.McpServer 5300 Standalone MCP tool server (Weather, Calculator, Time)
CopilotSDKPlayground.McpApi 5400 Copilot sessions powered by MCP tools via ModelContextProtocol SDK
CopilotSDKPlayground.AgentsApi 5500 Multi-agent patterns: Coordinator/Specialist + Orchestrator/SubAgent 
+------------------------------------------------------------------+
|                     .NET Aspire AppHost                          |
|                   (Aspire Dashboard + Redis)                     |
|                                                                  |
|  +----------+  +----------+  +-----------+  +------------+      |
|  |    Api   |  |  RagApi  |  | McpServer |  | AgentsApi  |      |
|  |streaming |  | TF-IDF   |  |  Weather  |  |Coordinator |      |
|  |  tools   |  | retrieval|  |  Calc     |  |Orchestrator|      |
|  |prompts   |  | grounded |  |  Time     |  |            |      |
|  |  Redis   |  | answers  |  +-----+-----+  +------------+      |
|  +----------+  +----------+        |                            |
|                             +------v------+                     |
|                             |   McpApi    |                     |
|                             |Copilot+tools|                     |
|                             +-------------+                     |
+------------------------------------------------------------------+

Prerequisites

Requirement Notes
.NET 10 SDK Version pinned in global.json
GitHub CLI winget install GitHub.cli
Copilot CLI extension gh extension install github/gh-copilot
GitHub authentication gh auth login
GitHub Copilot subscription Required for API access
Docker Desktop Required by Aspire for the Redis container
Visual Studio 2022 17.13+ or VS Code + C# Dev Kit

Quick Start

# 1. Clone
git clone https://github.com/yourusername/CopilotSDKPlayground.git
cd CopilotSDKPlayground

# 2. Restore
dotnet restore

# 3. Run all projects via Aspire (recommended)
dotnet run --project CopilotSDKPlayground.AppHost

Aspire starts all five projects plus a Redis container and opens the dashboard at https://localhost:17146.

Each project also runs standalone for focused development:

dotnet run --project CopilotSDKPlayground.Api
dotnet run --project CopilotSDKPlayground.RagApi
dotnet run --project CopilotSDKPlayground.McpServer  # start first when testing McpApi
dotnet run --project CopilotSDKPlayground.McpApi
dotnet run --project CopilotSDKPlayground.AgentsApi

Project Details

1. Api — Core Chat + Extended Features

Path: CopilotSDKPlayground.Api/ HTTP examples: CopilotSDKPlayground.Api/chat-examples.http

Demonstrates the full breadth of the Copilot SDK session capabilities.

Feature Endpoint group Description
Basic chat /api/chat Create / query / history / delete sessions
Streaming SSE /api/streaming Server-Sent Events responses via Channel<string>
Tool calling /api/tools AI-invoked functions (weather, calculator, clock) using AIFunctionFactory.Create
Prompt templates /api/prompts Parameterised system prompts with SystemMessageMode.Replace
Redis memory /api/memory Persistent conversation summaries stored in Redis

Key SDK patterns:

  • SessionConfig { Streaming = true } → AssistantMessageDeltaEvent.Data.DeltaContent
  • AIFunctionFactory.Create with local methods + [Description] attributes on parameters
  • SessionConfig.Tools = [ tool1, tool2, tool3 ]
  • SessionConfig.SystemMessage = new SystemMessageConfig { Mode = SystemMessageMode.Replace, Content = "..." }

2. RagApi — Retrieval-Augmented Generation

Path: CopilotSDKPlayground.RagApi/ HTTP examples: CopilotSDKPlayground.RagApi/rag-examples.http

A complete RAG pipeline built in pure C# with no vector database dependencies.

Architecture

User query
    |
    v
InMemoryVectorStore.Search(query, topK=3)   <- TF-IDF cosine similarity
    |                                          Sentence-aware sliding window chunking
    v                                          Sparse Dictionary<string, double> vectors
RagCopilotService.BuildAugmentedPrompt()    <- Injects retrieved chunks + similarity scores
    |
    v
Copilot SDK session                         <- Grounded response with inline citations

Documents are pre-seeded on startup:

  • .NET 10 Key Features
  • .NET Aspire Overview
  • GitHub Copilot SDK for .NET

Key implementation details:

  • Chunking: sentence-aware sliding window (TargetChunkWords=512, OverlapWords=52)
  • Vectorisation: log(1 + tf) weighting; stop-word filtered
  • Similarity: cosine on sparse dictionaries (no ML dependency)
  • System prompt: SystemMessageMode.Replace with explicit "only answer from context" instruction
Endpoint Method Description
/api/rag/documents GET List ingested documents
/api/rag/documents POST Ingest a new document (title + content + optional source)
/api/rag/documents/{id} DELETE Remove document and its chunks
/api/rag/sessions POST Create a RAG chat session
/api/rag/{sessionId}/query POST Query with retrieval — response includes retrievedChunks
/api/rag/{sessionId} DELETE Delete session

3. McpServer — Model Context Protocol Tool Server

Path: CopilotSDKPlayground.McpServer/ Package: ModelContextProtocol.AspNetCore 1.2.0

A stateless HTTP MCP server exposing three tools.

// The complete MCP server registration in Program.cs
builder.Services
    .AddMcpServer()
    .WithHttpTransport(options => options.Stateless = true)
    .WithTools<WeatherTool>()
    .WithTools<CalculatorTool>()
    .WithTools<TimeTool>();

app.MapMcp("/mcp");
Tool Name Description
WeatherTool get_weather Mock weather for 10 cities (Celsius/Fahrenheit)
CalculatorTool calculate Safe arithmetic via DataTable.Compute
TimeTool get_current_time Current time in any IANA timezone

Key pattern: [McpServerToolType] on the class + [McpServerTool(Name="...")] on each method. Stateless transport is recommended for HTTP-hosted servers that don't need server-initiated requests.

4. McpApi — Copilot + MCP Bridge

Path: CopilotSDKPlayground.McpApi/ HTTP examples: CopilotSDKPlayground.McpApi/mcp-examples.http Packages: GitHub.Copilot.SDK 0.1.29, ModelContextProtocol 1.2.0

Bridges the MCP server's tools into a Copilot SDK session. Copilot automatically calls tools during conversation.

Initialization flow

McpCopilotService.InitializeAsync()
    |
    +- HttpClientTransport({ Endpoint = "http://mcp-server/mcp" }, httpClient)
    |   +- Aspire service discovery resolves "mcp-server" hostname automatically
    |
    +- McpClient.CreateAsync(transport)
    |
    +- McpClient.ListToolsAsync()  ->  IList<McpClientTool>
                                        McpClientTool : AIFunction
                                                          |
                                         SessionConfig.Tools = [.. _mcpTools]
                                                          |
                                         Copilot SDK invokes tools transparently

Key insight: McpClientTool inherits AIFunction (from Microsoft.Extensions.AI), so MCP tools plug directly into SessionConfig.Tools without any adapter code.

Endpoint Method Description
/api/mcp/tools GET List discovered MCP tools
/api/mcp/sessions POST Create Copilot session with MCP tools loaded
/api/mcp/{sessionId}/messages POST Chat — Copilot calls MCP tools as needed
/api/mcp/{sessionId} DELETE Delete session

5. AgentsApi — Multi-Agent Orchestration

Path: CopilotSDKPlayground.AgentsApi/ HTTP examples: CopilotSDKPlayground.AgentsApi/agents-examples.http

Demonstrates two multi-agent patterns using only the Copilot SDK and ephemeral sessions.

Pattern A: Coordinator / Specialist

User task
    |
    v
Coordinator agent (ephemeral session)
    Returns JSON: { "agent": "Code|Research|Writing|Data", "reasoning": "..." }
    |
    v
Specialist agent (ephemeral session, dedicated system prompt)
    Returns: final answer

Specialists: Research, Code, Writing, Data — each with a focused system prompt via SystemMessageMode.Replace.

Endpoint: POST /api/agents/coordinator

Pattern B: Orchestrator / SubAgents (Parallel)

User goal
    |
    v
Orchestrator agent (ephemeral session)
    Returns JSON array: [{ "id", "description", "assignedAgent" }, ...]
    |
    v  Task.WhenAll  (true parallelism)
    +- SubAgent: Researcher  (ephemeral)
    +- SubAgent: Developer   (ephemeral)
    +- SubAgent: Analyst     (ephemeral)
    +- SubAgent: Writer      (ephemeral)
    |
    v
Synthesis agent (ephemeral session)
    Combines all sub-task results into a final response

Endpoint: POST /api/agents/orchestrator

Key pattern: All agent invocations use await using var session = await _client.CreateSessionAsync(...) — ephemeral sessions auto-disposed after each call, preventing accumulation.

Configuration

All projects share these configuration keys:

{
  "CopilotSDK": {
    "DefaultModel": "gpt-4o",
    "LogLevel": "info"
  }
}
Key Default Description
DefaultModel gpt-4o Fallback model when none is specified in the request
LogLevel info SDK log verbosity: debug | info | warn | error

McpApi also reads McpServer:BaseUrl (default: http://localhost:5300) when running without Aspire.

Available models

  • gpt-4o (default)
  • gpt-4
  • claude-sonnet-4.5
  • o1

Repository Structure

CopilotSDKPlayground/
+-- CopilotSDKPlayground.Api/           # Core chat + streaming/tools/prompts/memory
|   +-- Endpoints/
|   |   +-- ChatEndpoints.cs
|   |   +-- StreamingEndpoints.cs
|   |   +-- ToolsEndpoints.cs
|   |   +-- PromptTemplateEndpoints.cs
|   |   +-- MemoryEndpoints.cs
|   +-- Models/ChatModels.cs, ExtendedModels.cs
|   +-- Services/CopilotService.cs, StreamingCopilotService.cs, ToolCopilotService.cs, ...
|   +-- chat-examples.http
+-- CopilotSDKPlayground.RagApi/        # RAG pipeline
|   +-- Endpoints/DocumentEndpoints.cs, RagChatEndpoints.cs
|   +-- Models/RagModels.cs
|   +-- Services/DocumentChunker.cs, InMemoryVectorStore.cs, RagCopilotService.cs
|   +-- rag-examples.http
+-- CopilotSDKPlayground.McpServer/     # MCP tool server
|   +-- Tools/WeatherTool.cs, CalculatorTool.cs, TimeTool.cs
|   +-- Program.cs
+-- CopilotSDKPlayground.McpApi/        # Copilot + MCP bridge
|   +-- Endpoints/McpEndpoints.cs
|   +-- Models/McpModels.cs
|   +-- Services/McpCopilotService.cs
|   +-- mcp-examples.http
+-- CopilotSDKPlayground.AgentsApi/     # Multi-agent patterns
|   +-- Endpoints/AgentEndpoints.cs
|   +-- Models/AgentModels.cs
|   +-- Services/CoordinatorAgentService.cs, OrchestratorAgentService.cs
|   +-- agents-examples.http
+-- CopilotSDKPlayground.AppHost/       # Aspire orchestration (Redis + all 5 projects)
+-- CopilotSDKPlayground.ServiceDefaults/ # Shared OTel, health checks, resilience
+-- Directory.Build.props               # Shared build settings
+-- global.json                         # .NET 10 SDK pin

Observability

Run via Aspire for the full observability stack at https://localhost:17146:

Signal What you get
Traces Distributed tracing across all HTTP requests
Metrics ASP.NET Core, HTTP client, and runtime counters
Logs Structured logs correlated with trace and span IDs
Resources Live view of all 5 APIs + Redis container

Building

dotnet build
dotnet build -p:TreatWarningsAsErrors=true

Troubleshooting

Copilot CLI executable not found

winget install GitHub.cli
gh extension install github/gh-copilot
gh auth login
gh copilot --version  # verify

McpApi cannot connect to McpServer

When running standalone (without Aspire), start McpServer first, then McpApi. Override the URL in CopilotSDKPlayground.McpApi/appsettings.Development.json:

{ "McpServer": { "BaseUrl": "http://localhost:5300" } }

Redis connection failure

Redis is provided as a container by Aspire. For standalone development, start Redis locally:

docker run -p 6379:6379 redis:alpine

Port conflicts

Adjust ports in each project's Properties/launchSettings.json.

Contributing

  1. Fork the repository
  2. Create a feature branch: git checkout -b feature/my-feature
  3. Commit your changes: git commit -m 'Add my feature'
  4. Push: git push origin feature/my-feature
  5. Open a Pull Request

License

MIT — see LICENSE.

Resources

About

A demonstration of GitHub Copilot SDK capabilities using .NET 10 and .NET Aspire.

Topics

aspire net10 copilot-sdk

Resources

Readme

License

MIT license
Activity

Stars

0 stars

Watchers

0 watching

Forks

0 forks
Report repository

Releases

No releases published

Packages

 
 
 

Contributors

Languages