---
title: Quickstart
description: Create, exercise, package, and verify one typed Lenso Plugin.
---

In this self-contained quickstart, you will create one ordinary Plugin, invoke
it through a real Execution Adapter, and produce a verified `.lenso-plugin`
Bundle. You do not need a product Host or a catalog entry to complete it.

Rust produces portable Wasm plus a trusted Process implementation from the
same source. Bun uses the generated `@lenso/bun` runtime lowering.

## Prerequisites

- Rust stable with the `wasm32-unknown-unknown` target for the default scaffold;
- Bun 1.2.21 or newer only when selecting `--runtime bun`.

Install the CLI from npm:

```sh
npm install -g @lenso/cli
lenso --version
```

## Create and exercise a Plugin

Choose exactly one of the following paths and run it from a directory that does
not already contain `example.echo`.

### Rust

```sh
lenso plugin new example.echo
cd example.echo
lenso plugin check
lenso plugin dev \
  --implementation auto \
  --operation execute \
  --request-json '{"name":"example.echo","arguments_json":"{\"text\":\"hello\"}"}'
lenso plugin pack
cd ..
```

### Bun / TypeScript

```sh
lenso plugin new example.echo --runtime bun
cd example.echo
lenso plugin check
lenso plugin dev \
  --implementation auto \
  --operation execute \
  --request-json '{"name":"example.echo","arguments_json":"{\"text\":\"hello\"}"}'
lenso plugin pack
cd ..
```

In the Bun path, business changes live in `example.echo/src/plugin.ts`. The
generated entrypoints own Descriptor projection, development invocation, and
the production Bun server; business code does not implement JSON-RPC or process
lifecycle.

In either path, append `--watch` to the same `plugin dev` invocation, retaining
its operation and request arguments, to rebuild and rerun after source changes.
The development build stays unoptimized. `plugin pack` performs the
release build, reopens the resulting `.lenso-plugin` archive through the same
verifier used for installation, and prints its verified path under `dist/`.
Both paths then return to the parent directory so the Bundle is available at
`./example.echo/dist/example.echo-0.1.0.lenso-plugin`. That completes this
quickstart; it does not assume an unpublished catalog entry or a product Host
that is not on your machine.

## Connect the Bundle to an App

An App is derived from one exact Host Build, its matching Host Catalog, and a
visible Plugin Root. Those artifacts belong to the product Host rather than to
the generic CLI. Once you have that matching pair, follow
[Change your first App](/docs/core/first-app-change) to initialize a workspace,
add the local Bundle, inspect the derived App, run it, and remove the change.
Catalog installation is an optional path and only applies to a Release that
the selected catalog actually returns.

Run `lenso doctor` when setup or resolution fails. It emits human-readable
checks by default and stable JSON with `--json`.

Continue with [Change your first App](/docs/core/first-app-change),
[Plugin authoring](/docs/core/plugin-authoring), or
[Bun Plugin authoring](/docs/core/bun-plugin-authoring).