# How to embed the StackQL MCP server in a .NET application

> Embed the StackQL MCP server in a .NET / C# app as a sidecar or vendored bundle, so a worker service or agent can run cloud queries and drift checks over SQL with no runtime dependency.

Source: https://stackql.io/ai/how-tos/embed-stackql-mcp-server-in-dotnet

StackQL's MCP server can run inside a .NET application with no separate install and no runtime dependency. The `StackQL.Mcp` package spawns the signed StackQL binary over stdio behind the official C# MCP SDK client, so a worker service or agent gets a governed, self-describing SQL interface to every cloud and SaaS provider in the StackQL registry. This is the pattern behind **driftwatch**, a scheduled drift-check worker service.

## Steps

1. **Add the package:**

```
dotnet add package StackQL.Mcp
```

An optional `StackQL.Mcp.AgentFramework` package adds Agent Framework integration. Requires .NET 8 or later (the packages multi-target `net8.0` and `net9.0`).

2. **Start the server and call a tool.** The builder defaults to `StackqlMode.ReadOnly`:

```csharp
using StackQL.Mcp;

await using var server = await StackqlMcp.CreateBuilder()
    .WithMode(StackqlMode.ReadOnly)
    .WithAuth("github", "null_auth")
    .StartAsync();

var tools = await server.ListToolsAsync();
var result = await server.CallToolAsync("list_services",
    new() { ["provider"] = "github", ["row_limit"] = 5 });
```

The builder also exposes `.WithBinary()`, `.WithBundlePath()`, `.WithApproot()`, and `.WithCommand()`.

3. **Choose a mode.** `.WithMode()` defaults to `StackqlMode.ReadOnly`. Set `StackqlMode.Safe`, `StackqlMode.DeleteSafe`, or `StackqlMode.FullAccess` only when the app needs to provision. Escalation is explicit.

## Ship a self-contained executable

Two ways to source the binary:

- **Sidecar (default)** - the platform bundle is downloaded on first run, sha256-verified, cached at `~/.stackql/mcp-server-bin/<version>/<platform-key>/`, and spawned over stdio.
- **Vendored** - embed the bundle as a build resource:

```
dotnet build -p:StackqlVendorBundle=/path/to/stackql-mcp-windows-x64.mcpb
```

Override the binary or bundle at runtime with the `STACKQL_MCP_BIN` or `STACKQL_MCP_BUNDLE` environment variables.

## Demo app

**driftwatch** is a .NET Worker Service that embeds the read-only StackQL server and, on a schedule, runs a suite of SQL drift checks (public exposure, missing tags or licenses, baseline drift) and posts the findings to a Teams Adaptive Card.

## Related concepts

- [Embedded MCP: .NET / C# reference](/mcp/embedded/dotnet) - install, API, and vendoring
- [How to use StackQL with AI agents](/ai/how-tos/use-stackql-with-ai-agents) - the MCP model and safety modes
- [StackQL MCP Architecture](/ai/architecture/stackql-mcp-architecture) - transports, modes, and audit internals
- [What is Agentic Infrastructure?](/ai/canonical-definitions/what-is-agentic-infrastructure) - the pattern this enables