Copilot CLI IDE Bridge for Visual Studio

A Visual Studio extension that enables GitHub Copilot CLI to interact with Visual Studio via the /ide command — the same way it works with VS Code.

How It Works

Package loads when a solution is opened in Visual Studio (ProvideAutoLoad)
RPC server starts on a named pipe, exposing VS services (DTE, diff, diagnostics)
MCP server process launches as a separate net10.0 child process, connecting back to VS via RPC
Lock file written to ~/.copilot/ide/ with the MCP pipe path, auth nonce, and workspace folders
Copilot CLI discovers the lock file via /ide, connects, and calls MCP tools to interact with VS
Solution changes tracked — when you close/open solutions, the lock file's workspace folders update automatically
Stale files cleaned — on startup, lock files and log files from dead processes are removed

Getting Started

Prerequisites

Visual Studio 2022 (v17.x) or Visual Studio 2026 (v18.x)
GitHub Copilot CLI installed
An active Copilot subscription
.NET 10.0 SDK (for the MCP server process)

Build & Install

# Clone and build
git clone https://github.com/sailro/CopilotCliIde

# Build both the VSSDK package and the MCP server
dotnet build src/CopilotCliIde.Server/CopilotCliIde.Server.csproj
dotnet build src/CopilotCliIde/CopilotCliIde.csproj

# The .vsix is produced at:
# src/CopilotCliIde/bin/Debug/CopilotCliIde.vsix

Double-click the .vsix to install, or use F5 in Visual Studio to debug in the experimental instance.

Usage

Open a solution in Visual Studio — the extension activates automatically
Open Copilot CLI in a terminal, with the working directory matching the solution folder
Run /ide in Copilot CLI — it discovers Visual Studio and connects

$ copilot
> /ide
  ✓ Connected to Visual Studio (CopilotCliIde)

Once connected, the agent can:

Query solution info — ask "What solution is open?"
Read file content — from disk, with line range support
See your selection — ask "What text do I have selected?"
Propose diffs — the agent opens a real VS diff view using IVsDifferenceService
Check diagnostics — get errors and warnings from the VS Error List

MCP Tools

The extension exposes 7 MCP tools to the Copilot CLI agent:

Tool	Description
`get_vscode_info`	Solution path, name, project list
`get_selection`	Active editor selection: text, file path, line/column range
`get_diagnostics`	Errors and warnings from the VS Error List (filterable by URI)
`read_file`	Read file content from disk (supports line ranges)
`open_diff`	Open a real VS diff view comparing original with proposed changes. Blocks until user acts.
`close_diff`	Close a diff tab by its tab name
`update_session_name`	Set the CLI session display name

Tool Details

`get_vscode_info`

Returns information about the current Visual Studio instance:

{
  "ideName": "Visual Studio",
  "solutionPath": "C:\\Dev\\myproject\\MyProject.sln",
  "solutionName": "MyProject",
  "solutionDirectory": "C:\\Dev\\myproject",
  "projects": [{ "name": "MyProject", "fullName": "..." }],
  "processId": 12345
}

`get_selection`

Returns the current editor selection, read on-demand from DTE:

{
  "current": true,
  "filePath": "C:\\Dev\\myproject\\Program.cs",
  "selectedText": "Console.WriteLine(\"Hello\");",
  "startLine": 10,
  "startColumn": 8,
  "endLine": 10,
  "endColumn": 35,
  "isEmpty": false
}

`get_diagnostics`

Returns errors and warnings from the Visual Studio Error List. Accepts an optional uri parameter to filter by file:

{
  "diagnostics": [
    {
      "severity": "vsBuildErrorLevelHigh",
      "message": "The name 'x' does not exist in the current context.",
      "file": "C:\\Dev\\myproject\\Program.cs",
      "line": 12,
      "column": 5,
      "project": "MyProject"
    }
  ]
}

`read_file`

Reads file content from disk with optional line range:

{
  "filePath": "C:\\Dev\\myproject\\Program.cs",
  "content": "using System;\n...",
  "totalLines": 42,
  "startLine": 1,
  "linesReturned": 10
}

`open_diff` / `close_diff`

The diff workflow lets the agent propose changes that you review in VS:

Agent calls open_diff with original_file_path, new_file_contents, and tab_name → a real VS diff view opens via IVsDifferenceService
You review the changes in the native diff viewer
Agent calls close_diff with the same tab_name to close the diff tab

Note: Tool names and schemas match VS Code's Copilot Chat extension exactly (get_vscode_info, get_selection, open_diff, close_diff, get_diagnostics, update_session_name) to ensure full compatibility with the Copilot CLI /ide protocol.

Architecture

Protocol Stack

MCP Transport: Windows named pipe (\\.\pipe\mcp-{uuid}.sock) with HTTP/1.1 + Nonce auth
RPC Transport: Windows named pipe (\\.\pipe\copilot-cli-rpc-{uuid}) with StreamJsonRpc
Discovery: Lock files in ~/.copilot/ide/{uuid}.lock
Diagnostics: Per-process log files in ~/.copilot/ide/ (vs-error-{pid}.log, vs-connection-{pid}.log)

Lock File Format

{
  "socketPath": "\\\\.\\pipe\\mcp-{uuid}.sock",
  "scheme": "pipe",
  "headers": { "Authorization": "Nonce {uuid}" },
  "pid": 12345,
  "ideName": "Visual Studio",
  "timestamp": 1672531200000,
  "workspaceFolders": ["C:\\Dev\\myproject"],
  "isTrusted": true
}

License

MIT

Copilot CLI IDE Bridge

Sebastien Lebreton