> ## Documentation Index
> Fetch the complete documentation index at: https://docs.harboros.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Core concepts

> The handful of ideas that make HarborOS click — and where to read more on each.

HarborOS is built on a few ideas. Grasp these and everything else in the product follows. Each links to a fuller explanation when you want it.

## Everything is built from your contracts

The contract is the foundation. ARR, renewals, churn, expansion, your forecast — all of them are derived from your contracts, not maintained separately. That's why the numbers always agree and every figure traces back to a contract. See [Contract is the atom](/concepts/contract-is-the-atom).

## The screens are views, not separate tools

Compass, Renewals, Reports, Metrics — these aren't different products with their own numbers. They're different views, or lenses, on the same contracts. Pipeline is the one exception: it holds deals you haven't signed yet, which become contracts when they close. See [Lenses](/concepts/lenses).

## Nothing counts until you decide

HarborOS gathers your deals and contracts and does the math, but it never decides what your numbers are. A deal counts when you promote it; a contract counts when you confirm it; a renewal is shaped by the call you make on it. The judgment stays yours, which is what makes the numbers defensible. See [Judgment is the gate](/concepts/judgment-is-the-gate).

## Go deeper

When you're ready, the [Concepts](/concepts/contract-is-the-atom) section covers the rest: how the [lifecycle](/concepts/lifecycle-model) is worked out, how [Portolan](/concepts/portolan) preserves what you believed over time, and how [Beacon](/concepts/beacon) answers questions from your real data.