LaunchDarkly AI SDK for Go

Warning

This SDK is in early development (version 0.x) and is not yet recommended for production use. Public APIs may change in breaking ways between releases while it is hardened toward a 1.0 release. Please report problems and feedback through GitHub issues.

LaunchDarkly AI SDK for Go. Manage prompts, models, tools, and agent graphs as AI Configs, target and roll them out per user, score quality with judges, and track cost, latency, and errors. Handlers for OpenAI, Anthropic, Bedrock, and LangChain.

go get github.com/launchdarkly/go-ai-sdk/aiserver
go get github.com/launchdarkly/go-ai-sdk/claudemessages   # plus the handlers you use

Requires Go 1.26.

Layout

Package	Tier	What it does
aiserver	0	Core client: Config, Graph, ResolveGraph, InspectConfig, registry, lifecycle, judges, telemetry
aiserver/experimental	0	Experimental entry point: Agent Skills, Evaluations from Code
claudemessages	1	Anthropic Messages API handler — {Anthropic, messages}
openaimessages	1	OpenAI Responses API handler — {OpenAI, messages}
bedrockmessages	1	Amazon Bedrock Converse handler — {Bedrock, messages}
langchainmessages	1	langchaingo handler for any provider — {*, messages}
claudeagents	1	Anthropic agent handler, ClaudeGraph, ToClaudeAgents — {Anthropic, agent}
openaiagents	1	OpenAI agent handler, OpenAIGraph, ToOpenAIAgents — {OpenAI, agent}
bedrockagents	1	Bedrock agent handler, BedrockGraph — {Bedrock, agent}
langchainagents	1	langchaingo + langgraphgo agent handler, LangChainGraph, ToLangGraph — {*, agent}
examples	—	Integration entry point

langchainmessages and langchainagents use community Go ports of LangChain and LangGraph (tmc/langchaingo, smallnest/langgraphgo). claudeagents runs the Claude Code built-in tools on the host itself (see its README's security note). Each package README lists what its Go version does differently.

Quick start

ctx := context.Background()
if _, err := aiserver.InitClient(ctx, aiserver.InitOptions{}); err != nil { // LD_SDK_KEY
	log.Fatal(err)
}
defer aiserver.Shutdown(ctx)
user := ldcontext.New("user-123")

// 1. One handler.
claude := claudemessages.NewHandler(claudemessages.Options{})
resp, err := aiserver.Config(aiserver.ConfigArgs{Key: "summariser", Handlers: []*aiserver.ProviderHandler{claude}}).
	Invoke(ctx, "What is a feature flag?", user,
		aiserver.WithVariables(map[string]any{"tone": "brief"})) // optional; also WithHistory(msgs)
if errors.Is(err, aiserver.ErrConfigDisabled) {
	// the variation is off: serve a fallback
}
fmt.Println(resp.Text()) // string response, or structured output as JSON

// 2. Several providers: the variation's provider and mode choose.
openai := openaimessages.NewHandler(openaimessages.Options{})
cfg := aiserver.Config(aiserver.ConfigArgs{Key: "summariser", Handlers: []*aiserver.ProviderHandler{claude, openai}})
for ev, err := range cfg.Stream(ctx, "Hello", user) {
	if err != nil {
		log.Fatal(err)
	}
	if ev.Type == aiserver.EventChunk {
		fmt.Print(ev.Text)
	}
}

// 3. A multi-agent graph.
agents := []*aiserver.ProviderHandler{claudeagents.NewHandler(claudeagents.Options{}), openaiagents.NewHandler(openaiagents.Options{})}
out, err := aiserver.Graph("travel-agent-flow", aiserver.GraphOptions{Handlers: agents}).
	Invoke(ctx, "Plan a week in Lisbon", user)

// 4. A registry: build handlers and tools once, then share them.
registry := aiserver.NewRegistry(aiserver.RegistryEntries{
	Handlers: []*aiserver.ProviderHandler{claude, openai},
	Tools:    map[string]aiserver.ToolHandler{"get-weather": aiserver.ToolFunc(getWeather)},
})
resp, err = aiserver.Config(aiserver.ConfigArgs{Key: "summariser", Registry: registry}).Invoke(ctx, "Hi", user)
out, err = aiserver.Graph("travel-agent-flow", aiserver.GraphOptions{Registry: registry}).Invoke(ctx, "Plan a week in Lisbon", user)

ResolveGraph takes the same GraphOptions.Registry. Handlers and tools passed directly on a call take precedence over the registry's.

Failures are sentinel errors for errors.Is: ErrNotInitialized, ErrConfigNotFound, ErrConfigDisabled, ErrNoHandler, ErrGraphDisabled (see aiserver/README.md).

Configuration

• SDK key: LD_SDK_KEY, or aiserver.InitOptions{SDKKey: ...}, or bring your own client with aiserver.InitWithClient.
• Non-production LaunchDarkly: InitOptions{BaseURI, StreamURI, EventsURI}, or the LD_*_URI variables below.

An InitOptions field that is set wins over its variable. Blank values count as unset.

Variable	Required	Description
LD_SDK_KEY	yes, unless InitOptions.SDKKey or InitWithClient	LaunchDarkly server-side SDK key; also stamped as highlight.project_id
LD_BASE_URI	no	LaunchDarkly polling/base URI for non-production environments
LD_STREAM_URI	no	LaunchDarkly streaming URI
LD_EVENTS_URI	no	LaunchDarkly events URI
OTEL_EXPORTER_OTLP_ENDPOINT	no	OTLP/HTTP trace endpoint (/v1/traces is appended); default https://otel.observability.app.launchdarkly.com
LD_SERVICE_NAME	no	service.name resource attribute; default go-sdk
LD_ENVIRONMENT	no	deployment.environment resource attribute; omitted when unset
LD_ENVIRONMENT_ID	no	LaunchDarkly environment ID for AI Config Monitoring trace correlation (environmentId / feature_flag.set.id); omitted when unset
LD_API_TOKEN	only for Evaluations from Code	LaunchDarkly API access token (experimental)

• Providers: each handler reads its provider's usual environment (ANTHROPIC_API_KEY, OPENAI_API_KEY, the AWS credential chain / AWS_BEARER_TOKEN_BEDROCK) unless you inject a client.

Telemetry

InitClient registers a global OpenTelemetry tracer provider: OTLP/HTTP with gzip to InitOptions.OTLPEndpoint, else OTEL_EXPORTER_OTLP_ENDPOINT, else aiserver.DefaultOTLPEndpoint; resource attributes highlight.project_id (SDK key), service.name (LD_SERVICE_NAME, default go-sdk) and deployment.environment (LD_ENVIRONMENT, when set); W3C propagators; and a span processor that stamps gen_ai.conversation.id from aiserver.WithConversationID. Handler spans carry prompt and completion content.

Development

go mod download   # fetch dependencies
make build        # build every package, including the examples
make test         # go test -race ./...
make lint         # gofmt check + go vet

.env.example lists the environment variables the SDK and the examples read; the SDK does not load a .env file itself, so export them in your shell or with your own tooling. Contributor and architecture notes are in AGENTS.md.

License

Apache 2.0. See LICENSE.

Examples run against a real LaunchDarkly environment — see examples/README.md.