# Core concepts

*The handful of ideas that everything in Tredy is built on.*

## Service

A **service** is a unit of work Tredy performs end to end. Each service is an
org-owned, **versioned definition** (with a `slug`, a capability manifest, and a
deliverable contract) that produces runs and delivers outcomes.

## Run

A **run** is a single execution of a service. Runs move through stages, can be
paused, resumed, or cancelled, and can pause for a **human-in-the-loop** decision
before continuing.

## Outcome

An **outcome** is the delivered work product of a run — a surface to inspect,
trust, change, approve, export, and route. Every outcome carries a **Proof Rail**
(evidence, source versions, method, cost, and the approval trail) and a
**Needs You** section that surfaces the real human decisions. Recurring services
**reconcile** their runs so you track one living result over time.

## Knowledge layer

Your org's documents, connected tools, and **business profile** form a knowledge
layer that services draw on to ground their work.

## Organization

Everything is scoped to an **organization** — members and roles, connected tools,
knowledge, services, and billing all live at the org level.