Call local MCP tools from C#

This executable consumer uses the packed Hosting library to discover and call an ordinary text-normalization tool. It checks both explicitly selected MCP revisions, host status, tool-level errors and the expected result. No AI model, account, network listener or Docker service is needed.

McpMethods.ListTools and McpMethods.CallTool are public constants in Hosting 0.7.0.

From the repository root, with the SDK in global.json and Node installed:

./scripts/prepare-core-packages.sh
npm ci --prefix tests/mcp --ignore-scripts
dotnet restore examples/mcp --force --force-evaluate --no-cache
dotnet run --project examples/mcp -c Release -- "$(command -v node)" "$PWD/tests/mcp/server.mjs"

The explicit restore refreshes locally rebuilt package hashes, as in the native SDK examples. Release qualification separately rejects dependency-topology drift and freezes the actual tested package bytes.

Expected output:

Mcp20251125: hello world
Mcp20260728: hello world

The server is the repository's official TypeScript SDK fixture, reused so documentation and interoperability tests exercise the same implementation. Its dependencies are development-only. In your application, deploy your own reviewed MCP server and replace the absolute executable/script paths; Hosting never installs server dependencies for you.

The host starts a separate server process for each binding and disposes it deterministically. One server can expose many tools. Existing native Python/TypeScript plugins continue to use their own SDK and can coexist in the same host. MCP bindings do not accept native callback grants. structuredContent.text is this example's output contract; other servers may return only content.

This is a local tools subset, validated on macOS arm64 against the official TypeScript SDK. It does not qualify arbitrary MCP SDKs, remote HTTP or untrusted-code containment. See the complete guide for versions, limits, pagination and cancellation.