---
title: Introduction
description: Understand what Smithers is, how the CLI and JSX API fit together, and when the workflow runtime is worth using.
---

Think of Smithers as a runtime for [durable agent work](/concepts/execution-model).

If React turns state into UI, Smithers turns state into executable work. Each render answers one question: given what has already completed, what can run now?

That matters because real agent jobs do not stay single-step for long. A useful task becomes:

- analyze a codebase
- propose a fix
- apply the fix
- run validation
- ask for [approval](/concepts/approvals)
- [resume later](/concepts/suspend-and-resume) if the process crashes

You can script all of that by hand. Most teams do at first. Then the retries, [persistence](/concepts/workflow-state), audit trail, and [branching logic](/concepts/control-flow) start taking over the project. Smithers exists to make that coordination the default instead of the afterthought.

## The Three Surfaces

### CLI

The CLI is the operations surface. You use it to scaffold workflow packs, launch runs, inspect state, read logs, answer [approvals](/concepts/approvals), send [signals](/components/signal), and recover from failure.

Start with [CLI Quickstart](/cli/quickstart) if that is your immediate job.

### JSX API

The JSX API is the authoring surface. You describe the workflow as a tree of [`<Workflow>`](/components/workflow), [`<Task>`](/components/task), and [control-flow components](/concepts/control-flow), and Smithers repeatedly renders that tree as outputs become available.

Start with [JSX API](/jsx/overview) if you are building workflows.

### Runtime

The runtime is the durable engine beneath both surfaces. It validates [structured output](/guides/structured-output), persists it to [SQLite](https://sqlite.org), emits [events](/runtime/events), and resumes safely after interruption.

Start with [Workflows Overview](/concepts/workflows-overview) if you want the model before the mechanics.

## What Happens During a Run

1. Smithers renders your workflow tree with the current `ctx`.
2. It finds the tasks that are ready to execute.
3. It runs those tasks and validates their outputs.
4. It persists the outputs and runtime metadata to SQLite.
5. It renders again with the updated state.

That loop continues until the workflow finishes, fails, pauses for [human input](/concepts/human-in-the-loop), or is cancelled.

## When Smithers Is the Right Tool

Use Smithers when:

- order matters across multiple AI or compute steps
- you need [resumability](/guides/resumability) or crash recovery
- humans must [approve](/concepts/approvals) or answer questions mid-run
- different tasks need different [models](/guides/model-selection), [tools](/integrations/tools), or policies
- you want the workflow itself to stay readable and testable

If you only need one prompt and one response, a workflow is probably overkill.

## Read Next

- [Installation](/installation) to get the workflow pack into your project.
- [Quickstart](/quickstart) for the fastest first run.
- [CLI Quickstart](/cli/quickstart) to learn the operational flow.
- [JSX Quickstart](/jsx/quickstart) to build a workflow from scratch.
- [Workflows Overview](/concepts/workflows-overview) for the mental model.
- [Execution Model](/concepts/execution-model) to understand how renders, state, and resumability fit together.