The coding assistant now has a model, Harness runtime, read-only tools, durable sessions, a workspace, and optional confined process execution. Join those pieces in main.go; the CLI remains presentation code around a Session.

Assemble main

func main() {
	// Linux re-exec dispatch must happen before flag parsing or runtime setup.
	sandbox.Init()

	question := flag.String("ask", "Summarize this repository.", "question for the coding assistant")
	resume := flag.String("session", "", "existing session ID to restore")
	data := flag.String("data", "./agent-data", "durable application data")
	flag.Parse()

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer cancel()

	if err := runCLI(ctx, *data, *resume, *question); err != nil {
		log.Fatal(err)
	}
}

runCLI constructs the client, stores, workspace store, sandbox runner, Loop, and Rig using the functions from the preceding pages. Keep ownership in this composition root so shutdown is visible.

Run a new session

# The exact provider variables come from the model page.
export LOOPRIG_MODEL="your-model-name"
export OPENAI_API_KEY="your-api-key"
go run . -ask "Which package owns session restoration?"

Print the new session ID before waiting for the terminal event:

session=8c7a3e74-6d4d-4d37-a6b7-1a8a22f9e418
assistant=Session restoration is owned by Harness session runtime and sessionstore.

Actual text depends on the selected model and the evidence returned by tools.

Resume a session

# Supply the ID printed by the earlier invocation.
go run . -session 8c7a3e74-6d4d-4d37-a6b7-1a8a22f9e418 -ask "What did we inspect previously?"

Restoring the Session replays durable state and resumes the same identity. It does not automatically recreate an unpersisted external service or silently accept configuration drift.

Shutdown order

Use defer immediately after each successful acquisition, but understand the intended order:

// Stop accepting work, drain the Session, and close subscriptions first.
defer live.Shutdown(context.Background())
// Then close executor-owned processes and isolated runtime paths.
defer executors.Close()
// Close the underlying durable backend after every Session has stopped.
defer disk.Close()

Handle SIGINT and SIGTERM through a context, but use an independent bounded cleanup context when a canceled request context would prevent leases and resources from being released.

Runnable checkpoint

The complete Harness quickstart is a runnable CLI-shaped application with a model client, Loop, Rig, Session, subscription, submission, terminal event, and shutdown. Its deterministic model lets the exact-output test run without a provider key. Replace that boundary with openAI or your chosen provider to run the coding assistant.

Continue to choose an interface and extend the agent.