/CHANGELOG.md

Changelog

All notable changes to Go Micro are documented here.

Format follows Keep a Changelog. Go Micro uses calendar-based versions (YYYY.MM) for the AI-native era.

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[Unreleased]

Added

• MCP gateway benchmarks — comprehensive benchmark suite for tool listing, lookup, auth, rate limiting, and JSON serialization (gateway/mcp/benchmark_test.go)
• Workflow example — cross-service orchestration demo with Inventory, Orders, and Notifications services showing agents chaining multi-step workflows from natural language (examples/mcp/workflow/)
• Docker Compose deployment — production-like setup with Consul registry, standalone MCP gateway, and Jaeger tracing in one docker-compose up (examples/deployment/)

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[2026.03] - March 2026

Added

Developer Experience

• micro new MCP templates — micro new myservice generates MCP-enabled services with doc comments, @example tags, and WithMCP() wired in. Use --no-mcp to opt out.
• micro.New("name") unified API — single way to create services: micro.New("greeter") or micro.New("greeter", micro.Address(":8080")). Replaces micro.NewService() + service.New() dual API.
• service.Handle() simplified registration — register handlers with service.Handle(new(Greeter)) instead of manual server.NewHandler + server.Handle.
• micro.NewGroup() modular monoliths — run multiple services in one binary with shared lifecycle: micro.NewGroup(users, orders).Run().
• mcp.WithMCP() one-liner — add MCP to any service with a single option: micro.New("name", mcp.WithMCP(":3001")).
• CRUD example — contact book service with 6 operations, rich agent docs, and validation patterns (examples/mcp/crud/).

MCP Gateway

• WebSocket transport — bidirectional JSON-RPC 2.0 streaming over WebSocket for real-time agent communication (gateway/mcp/websocket.go).
• OpenTelemetry integration — full span instrumentation across HTTP, stdio, and WebSocket transports with W3C trace context propagation (gateway/mcp/otel.go).
• Standalone gateway binary — micro-mcp-gateway with Docker support for running the MCP gateway independently of services.
• Per-tool auth scopes — service-level (server.WithEndpointScopes()) and gateway-level (Options.Scopes) scope enforcement with bearer token auth.
• Rate limiting — per-tool token bucket rate limiting (Options.RateLimit).
• Audit logging — immutable audit records per tool call with trace ID, account, scopes, duration, and errors (Options.AuditFunc).

AI Model Package

• model.Model interface — unified AI provider abstraction with Generate() and Stream() methods.
• Anthropic Claude provider — model/anthropic with tool execution and auto-calling.
• OpenAI GPT provider — model/openai with provider auto-detection from base URL.

Agent SDKs

• LangChain SDK — contrib/langchain-go-micro/ Python package with auto-discovery, tool generation, and multi-agent workflow examples.
• LlamaIndex SDK — contrib/go-micro-llamaindex/ Python package with RAG integration examples.

Documentation

• AI-native services guide — building services for AI agents from scratch
• MCP security guide — auth, scopes, and audit logging
• Tool descriptions guide — writing doc comments that improve agent performance
• Agent patterns guide — architecture patterns for agent integration
• Error handling guide — writing agent-friendly error responses with typed errors
• Troubleshooting guide — common MCP issues and solutions
• Migration guide — add MCP to existing services in 5 minutes

CLI

• micro mcp serve — start MCP server (stdio for Claude Code, HTTP for web agents)
• micro mcp list — list available tools (human-readable or JSON)
• micro mcp test — test tools with JSON input
• micro mcp docs — generate tool documentation
• micro mcp export — export to LangChain, OpenAPI, or JSON formats

Agent Playground

• Chat-focused UI — redesigned playground with collapsible tool calls, real-time status, and thinking indicators
• Provider settings — configurable OpenAI/Anthropic provider, model, and API key

Changed

• Service interface moved to service.Service with micro.Service as a type alias for backward compatibility.
• service.New() returns service.Service interface (was *ServiceImpl).
• service.NewGroup() accepts service.Service interface (was *ServiceImpl).
• go.mod template in micro new updated to Go 1.22.

Fixed

• Handler Handle() method accepts variadic server.HandlerOption for scopes and metadata.
• Store initialization uses service name as table automatically.
• Service Stop() properly aggregates errors from lifecycle hooks.

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[2026.02] - February 2026

Added

• MCP gateway library — gateway/mcp/ with HTTP/SSE and stdio transports, service discovery, tool generation, and JSON schema generation from Go types (2,500+ lines).
• CLI integration — micro run --mcp-address flag to start MCP alongside services.
• Documentation extraction — auto-extract tool descriptions from Go doc comments with @example tag and struct tag parsing.
• Blog post — "Making Microservices AI-Native with MCP"
• MCP examples — examples/mcp/hello/ and examples/mcp/documented/

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[2026.01] - January 2026

Added

• micro deploy — deploy services to any Linux server via SSH + systemd with micro deploy user@server.
• micro build — build Go binaries and Docker images with micro build --docker.
• Blog post — "Introducing micro deploy"

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For earlier changes, see the git log.