Mirrorkit Go MCP Server

mirrorkit (Go)

A lightweight, drop-in production trace collector for LLM agents — the Go sibling of the Python mirrorkit and TypeScript mirrorkit (npm) packages.

It does exactly one thing: take traces you hand it and send them to your Mirrors backend — batched in the background, non-blocking, and safe (it never panics into your app after Init). It does not instrument SDKs and does not run agents; you build the trace, it ships it.

Install

go get github.com/ai-singhal/mirrorkit-go

Requires Go ≥ 1.21. Zero dependencies (standard library only).

Usage

package main

import (
	"time"

	mirrorkit "github.com/ai-singhal/mirrorkit-go"
)

func main() {
	mirrorkit.Init(mirrorkit.Options{APIKey: "mk_live_...", Project: "my-agent"})
	defer mirrorkit.Shutdown(5 * time.Second)

	mirrorkit.LogTrace([]mirrorkit.Message{
		mirrorkit.SystemMessage("You are a helpful assistant."),
		mirrorkit.UserMessage("What's the weather in Paris?"),
		mirrorkit.AssistantMessage("It's 18C and sunny."),
	}, mirrorkit.WithModel("claude-opus-4-8"))
}

Each trace is enqueued and flushed to {endpoint}/api/collect by a background goroutine (Authorization: Bearer <apiKey>, body {project, traces}).

Tool calls

Build tool-call and tool-result messages with the helpers:

mirrorkit.LogTrace([]mirrorkit.Message{
	mirrorkit.UserMessage("Cancel booking BK-4471."),
	mirrorkit.AssistantToolCalls(
		mirrorkit.NewToolCall("call_1", "cancel_booking", map[string]any{"id": "BK-4471"}),
	),
	mirrorkit.ToolResult("call_1", `{"status":"cancelled"}`),
	mirrorkit.AssistantMessage("Done — BK-4471 is cancelled."),
})

Options

mirrorkit.Init(mirrorkit.Options{
	APIKey:        "mk_live_...",           // required
	Project:       "my-agent",              // default "default"
	Endpoint:      "https://api.mirror.dev", // else MIRRORKIT_ENDPOINT / MIRROR_ENDPOINT / prod
	FlushInterval: 2 * time.Second,         // ms between background flushes
	MaxBatch:      50,                      // max traces per POST
	MaxQueue:      10_000,                  // in-memory cap; oldest dropped past this
	Debug:         false,                   // internal debug logs (or MIRRORKIT_DEBUG=1)
})

Endpoint resolution: Options.Endpoint → MIRRORKIT_ENDPOINT → MIRROR_ENDPOINT → the production default.

Lifecycle

mirrorkit.Flush(5 * time.Second)     // block until the queue drains
mirrorkit.Shutdown(5 * time.Second)  // stop the background goroutine (flushes first)

Prefer one collector per process via the package-level Init / LogTrace / Flush / Shutdown. For multiple independent collectors, use NewClient and call LogTrace / Flush / Shutdown on the returned *Client.

Testing

cd mirrorkit-go && go vet ./... && go test ./...