ContextManager

Structural C# context for AI coding agents, powered by Roslyn.
Navigate before you read.

Install • Tools • How to use it • FAQ • Full install guide

ContextManager is an MCP server that saves an agent from reading whole C# files. It does two things:

• Inspects files. It turns a .cs file into a JSON contract with its types, public members, constructor dependencies, base types, interfaces, and events. Method bodies, private members, and XML docs are left out; each method carries its line range so the agent can read only the body it needs.
• Maps the solution. It builds a knowledge graph of a .sln so the agent can find which files matter, and how risky a change is, before opening any of them.

Install

You need the .NET 10 SDK or later.

macOS / Linux:

curl -fsSL https://raw.githubusercontent.com/nushey/ContextManager/main/scripts/install.sh | bash

Windows (PowerShell):

irm https://raw.githubusercontent.com/nushey/ContextManager/main/scripts/install.ps1 | iex

The installer installs or updates the ContextManager .NET global tool and runs context-manager setup, a wizard that adds the server to the MCP clients you pick (Claude Code, Claude Desktop, Codex, Antigravity, Kilo Code, Cursor, Devin, Opencode).

To install by hand instead:

dotnet tool install -g ContextManager
claude mcp add --scope user context-manager -- context-manager   # Claude Code

For other clients, flags, config-file paths, and troubleshooting, see INSTALL.md.

project_scan on .NET Framework 4.8 solutions only works on Windows and needs Visual Studio Build Tools with the .NET desktop build tools workload. Everything else works on any platform.

Tools

Graph tools take the path of the .sln and keep the graph up to date on their own: before answering, they re-extract only what changed since the last scan. The graph is saved in .context-manager/<solution name>.graph.json next to the .sln, so every session on that solution shares it.

How to use it

Start from the file the user mentions:

1. inspect_file(path): read the type and build its node ID as Namespace.TypeName.
2. graph_get_dependencies(solutionPath, nodeId): find the neighbors worth reading.
3. inspect_file on those neighbors only.
4. graph_impact_analysis(solutionPath, nodeId): check the blast radius before changing anything.

A short impact list means the change is contained. A long one means the type's public contract is load-bearing and should be preserved; it does not mean the agent has to read every file in it.

Node IDs use Roslyn's fully qualified format, for example MyApp.Orders.OrderService or MyApp.Orders.OrderService.GetOrderAsync(System.Guid). Pass the IDs that the graph tools return as they are.

// graph_impact_analysis("/abs/path/MyApp.sln", "MyApp.Orders.IOrderRepository")
{
  "affectedIds": ["MyApp.Orders.OrderService", "MyApp.Api.OrdersController"],
  "affectedFiles": {
    "MyApp.Orders.OrderService": "/abs/path/Orders/OrderService.cs",
    "MyApp.Api.OrdersController": "/abs/path/Api/OrdersController.cs"
  }
}

To make your agent follow this workflow, copy docs/AGENTS-template.md into the AGENTS.md of your project.

FAQ

Is it a background service? No. It is an MCP stdio server: the client starts it when a session opens and stops it when the session ends.

What state does it keep? Only the graph files written next to each .sln. The inspection tools read the files you pass and keep nothing.

Does it read my whole solution? Only the graph tools do. inspect_file and inspect_context read just the files you give them.

Build and test

dotnet build
dotnet test

License

MIT © nushey