Define contracts once. Generate the transports, clients, docs, schemas, tools, and runtime glue that keep production code honest.

Documentation · Goa · Goa-AI · Examples · Discussions · Design First

Install the generator, describe a service, and let Goa create the boring parts.

go install goa.design/goa/v3/cmd/goa@latest

mkdir hello && cd hello
go mod init example.com/hello
mkdir design

package design

import . "goa.design/goa/v3/dsl"

var _ = Service("hello", func() {
	Method("say_hello", func() {
		Payload(func() {
			Field(1, "name", String)
			Required("name")
		})
		Result(String)

		HTTP(func() {
			GET("/hello/{name}")
		})
	})
})

goa gen example.com/hello/design
goa example example.com/hello/design
go run ./cmd/hello

From that one design, Goa generates server interfaces, transport adapters, clients, OpenAPI documentation, and command-line helpers. Your code stays focused on business behavior.

Goa-AI applies the same design-first contract model to agent systems:

• Typed tool contracts: Goa types, validations, examples, generated JSON Schema, and generated codecs.
• MCP integration: generated MCP servers and callers for exposing Goa services and consuming external tools.
• Structured completions: service-owned result schemas with unary and streaming helpers.
• Runtime policy: budgets, tool caps, confirmation gates, cancellation, retries, and bounded tool results.
• Durable execution: an in-memory development engine and a Temporal-backed production engine.
• Real-time products: typed stream events for assistant text, tool progress, awaits, child runs, usage, and status.

Start with the Goa-AI quickstart, then go deeper in the Goa-AI docs and repository guides.

• No drift: the design owns the contract; generated code, docs, schemas, and clients stay aligned.
• Less boilerplate: Goa generates the repetitive 30-50% of an API or agent system so teams build the behavior that matters.
• One contract, many surfaces: HTTP, gRPC, JSON-RPC, OpenAPI, clients, CLIs, tools, MCP adapters, and agent runtimes come from the same source.
• Production boundaries: business logic stays separate from transports, model providers, workflow engines, storage, and observability.

We are building Goa with people who care about typed contracts, generated infrastructure, clean service boundaries, and production-grade Go systems.

• Join the Goa Slack channel.
• Follow project updates on Design First.
• Ask questions and shape the roadmap in GitHub Discussions.
• Read the published documentation at goa.design.

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Goa Design is open source and community-built. The most helpful contributions come with a small design, a failing test, a clear reproduction, or a focused documentation improvement.

Start with the contributing guide and code of conduct, or browse good first issues.