MCPulse 0.1.0

MCPulse for .NET

Analytics for MCP servers, for the official C# MCP SDK.

using MCPulse;

McPulse.Configure(new McPulseOptions { Key = "mp_live_…" });

Then wrap each tool invocation:

return await McPulse.RecordAsync(
    toolName: request.Params.Name,
    arguments: request.Params.Arguments,
    clientName: server.ClientInfo?.Name,
    invoke: () => next(request, cancellationToken));

Best placed in whatever your host already uses to see every call — a CallTool handler wrapper, or the filter your server builder exposes.

Install

dotnet add package MCPulse

Zero package references. This library is loaded into other people's servers, and a transitive dependency that conflicts with what the customer already pins is a support burden with no upside. The canonicaliser, the HTTP call and the buffering are all in the base class library.

Options

An empty key turns it off, so a server started without its key configured is silent rather than a source of 401s on every flush.

One known gap

RecordAsync wraps your handler, so a throw arrives as a throw rather than as the isError result the server would have converted it into — that is what separates crashed from tool_error.

What it cannot see is bad_args. The .NET SDK binds and validates arguments before the handler runs, so a rejected argument set never reaches the wrapper. Reporting it anyway would mean reading the difference back out of an error message, and error strings are not an interface anyone promised to keep.

What leaves your process

Sizes and hashes. Arguments and results do not, and no option turns that on.

The three rules

1. Never throw. Every entry point swallows. Your exception is re-raised untouched; ours never reach you.
2. Never block. A bounded Channel with DropOldest means TryWrite never blocks and never fails — the same mechanism gives rule 2 and the memory ceiling at once.
3. Never store customer data. See above.

Cross-language consistency

ArgsHash is the first 12 hex characters of the SHA-256 of the RFC 8785 canonical form of the arguments. tests/MCPulse.Tests/canonical.json is the shared conformance suite every MCPulse SDK runs.

.NET needed two things undone and got one for free. System.Text.Json escapes <, > and & by default, and .NET's round-trip number format writes 1E+21 and 1E-07 where ECMAScript writes 1e+21 and 1e-7. The free part: RFC 8785 sorts keys by UTF-16 code unit, which is exactly StringComparer.Ordinal.

Running the tests

dotnet run --project tests/MCPulse.Tests

Licence

MIT