Onsol-GO/.agents/skills/developing-genkit-go/references/getting-started.md

Getting Started

Project Setup

mkdir my-genkit-app && cd my-genkit-app
go mod init my-genkit-app
go get github.com/genkit-ai/genkit/go@latest

Add provider plugin(s) for the models you want to use:

go get github.com/genkit-ai/genkit/go/plugins/googlegenai  # Google AI / Vertex AI
go get github.com/genkit-ai/genkit/go/plugins/anthropic     # Anthropic Claude
go get github.com/genkit-ai/genkit/go/plugins/compat_oai    # OpenAI-compatible
go get github.com/genkit-ai/genkit/go/plugins/ollama        # Ollama (local)

After writing your code, run go mod tidy to resolve all dependencies.

Initialization

Every Genkit app starts with genkit.Init, which returns a *Genkit instance:

import (
	"context"
	"github.com/genkit-ai/genkit/go/genkit"
	"github.com/genkit-ai/genkit/go/plugins/googlegenai"
)

ctx := context.Background()
g := genkit.Init(ctx,
	genkit.WithPlugins(&googlegenai.GoogleAI{}),
)

The *Genkit Instance

The *Genkit value g is the central registry. Pass it to every Genkit function:

// Defining resources
genkit.DefineFlow(g, "myFlow", ...)
genkit.DefineTool(g, "myTool", ...)
genkit.DefinePrompt(g, "myPrompt", ...)

// Generating content
genkit.GenerateText(ctx, g, ...)
genkit.Generate(ctx, g, ...)

Do not store g in a global variable. Pass it explicitly through your call chain.

Init Options

g := genkit.Init(ctx,
	// Register one or more plugins
	genkit.WithPlugins(&googlegenai.GoogleAI{}, &anthropic.Anthropic{}),

	// Set a default model (used when no model is specified)
	genkit.WithDefaultModel("googleai/gemini-flash-latest"),

	// Set directory for .prompt files (default: "prompts")
	genkit.WithPromptDir("my-prompts"),

	// Or embed prompts using Go's embed package
	// genkit.WithPromptFS(promptsFS),
)

Embedding Prompts

Use go:embed to bundle .prompt files into the binary:

//go:embed prompts
var promptsFS embed.FS

g := genkit.Init(ctx,
	genkit.WithPlugins(&googlegenai.GoogleAI{}),
	genkit.WithPromptFS(promptsFS),
)

Genkit CLI

The Genkit CLI provides a local Developer UI for running flows, tracing executions, and inspecting model interactions.

Install:

curl -sL cli.genkit.dev | bash

Verify:

genkit --version

Developer UI

Start your app with the Developer UI attached:

genkit start -- go run .

This launches:

• Your app (with tracing enabled)
• The Developer UI at http://localhost:4000
• A telemetry API at http://localhost:4033

Add -o to auto-open the UI in your browser:

genkit start -o -- go run .

The Developer UI lets you:

• Run and test flows interactively
• View traces for each generation call (inputs, outputs, latency, token usage)
• Inspect prompt rendering and tool calls
• Debug multi-step flows with per-step trace data

Without the CLI

Set GENKIT_ENV=dev to enable the reflection API without the CLI:

GENKIT_ENV=dev go run .

Import Paths

import (
	"github.com/genkit-ai/genkit/go/genkit"          // Core: Init, Generate*, DefineFlow, etc.
	"github.com/genkit-ai/genkit/go/ai"              // Types: WithModel, WithPrompt, Message, Part, etc.
	"github.com/genkit-ai/genkit/go/core"            // Low-level: Run (sub-steps), Flow types
	"github.com/genkit-ai/genkit/go/plugins/server"  // server.Start for HTTP
)