Build against Praecise from code.
The Harness SDK builds agents and workflows in TypeScript. The Cloud section of Praecise Spaces shows releases, environment and logs, and Skerry offers its own OpenAPI reference.
In short
The SDKs are the Harness SDK for agents and workflows in TypeScript, plus the Cloud section of Praecise Spaces for releases, environment and logs. They are for developers building against Praecise from code. Install @praecise/harness to start.
00
At a glance.
npm
@praecise/harness.
Apache-2.0, published on npm.
Runtime
Node 22 or newer.
No dependencies of its own.
Reference
Skerry OpenAPI 3.1.
Plus an MCP server and webhooks.
01
The SDK, without a folder.
The folder is the default and not the only way in. The same app can be a value you import.
import { createApp, agent, fn, guard } from "@praecise/harness";
const app = await createApp({
name: "acme",
agents: { support: agent({ role: "Help.", tools: ["lookup"] }) },
functions: { lookup: fn({ description: "Look up an order.",
input: { id: "the order id" }, effect: "read",
run: ({ id }) => ({ id, status: "delivered" }) }) },
guard: guard((a) => (a.effect === "write" ? "read-only today" : undefined)),
});
await app.ask("support", "where is order 12?");createApp refuses to start a faulted app.
02
What the SDK gives you.
- 01
createApp and defineApp
An app as a value.
For packages, edge workers and apps assembled per tenant.
- 02
mergeApps
Build on a library.
Later definitions win and collisions are reported.
- 03
agent, fn, guard
The three nouns.
An agent, a function it may call, and the boundary on what runs.
- 04
Ask and rate
Calls and feedback.
app.ask, app.rate and ceiling and floor to bound one request.
- 05
Package it
Hand an app to someone else.
praecise package writes a directory with a launcher and an mcp.json describing the tool surface.
- 06
Import it
An app as a library.
A packaged app is importable, with api.d.ts listing the tools.
- 07
Serve it
Over stdin or HTTP.
praecise mcp serves over stdin and stdout; praecise dev serves HTTP.
- 08
Bring your own
Models, stores, storage.
Or bring one key for Praecise Cloud's managed side.
03
Other entry points.
- 01
Releases, environment and logs for each project.
- 02
OpenAPI 3.1, MCP server and webhooks.
- 03
Depend on praecise-runtime; it defaults to no backend.
04
Start.
1
Install.
npm i @praecise/harness, or npx @praecise/harness init my-app.
2
Run.
npx @praecise/harness dev.
3
Place.
Place the folder behind the edge as a Node app.
05
Next pages.
06
Praecise accounts are by invitation. Open the console, or talk to us.
New to Praecise Cloud? Accounts are set up with the Praecise team: talk to us, then sign in to the Cloud section of Praecise Spaces with an email code.