> ## Documentation Index > Fetch the complete documentation index at: https://docs.cfo.ai/llms.txt > Use this file to discover all available pages before exploring further. # How cfo.ai works > How your Model fits together: your workspace, Variables, Dimensions, formulas, Pages, connected data, Scenarios, and Ari, and why an answer from Ari leaves behind work you can open and change. cfo.ai is built around one shared financial Model of your business. Ari, your AI finance coworker, answers your questions by reading and building that Model, and you can open, check, and change everything it builds. An answer from Ari leaves behind work you can use again. ## Your workspace A workspace is your company's home in cfo.ai. It holds the Model, the Pages that present it, the Scenarios you are testing, the systems you connected, and your team. Everything you or Ari build in the Model belongs to the workspace, not to a single chat. Three things are yours rather than the workspace's: your chats with Ari, and the files in them, which only you can open; your Skills, which go with you to every workspace where you are a member unless you limit one to a single workspace; and your Triggers, which nobody else can see or change. See [What Ari remembers](/concepts/ari-memory.md#files-from-your-other-chats) and [Skills, Triggers, and Guides](/concepts/automation.md). ## How your Model fits together The Model is a live representation of how your business works across time. Three ideas carry it: * Variables hold the values you care about, such as Revenue, Headcount, or Cash, and the assumptions behind them, such as a price. A Variable holds a value in each period it covers, and in each business category it is broken down by. * Dimensions organize those values into business categories, such as Department, Product, or Region, so Revenue can be read by Product as well as in total. * Formulas connect Variables to each other, so a change in one place flows to everything that depends on it. Take a hiring decision. Two engineers start in March. Headcount rises in March, payroll rises with it, expenses follow, and the cash balance in every later month goes down. You change one assumption, and the Model recalculates the rest. The timeline has two parts. Months up to your **Last close** are Actuals, usually read from your accounting system. Later months are the Forecast, calculated from your assumptions. See [Actuals, Forecast, and Last close](/concepts/actuals-and-forecast.md). ## Pages present the Model A Page is a report built from blocks: Table blocks that show Variables across time, Canvas blocks that draw charts and other visuals, and Text blocks for notes. Pages do not hold copies of numbers. A board report, a hiring plan, and a cash forecast can all show the same Cash Variable, and when Cash changes, every Page shows the new value. See [Pages, Table blocks, and Canvas blocks](/concepts/pages-and-blocks.md). ## Ari works on the same Model you do When you ask Ari a question, it reads the Model, your connected data, and the Page you have open. When the answer needs something new, such as a forecast or a hiring Scenario, Ari builds it into the Model as Variables, formulas, and Pages. The result stays after the chat ends, and you can open it, trace any number to its source, and change it yourself. Every change to the Model, yours or Ari's, is recorded in version history. See [How Ari works with you](/concepts/working-with-ari.md). Ari does not do the arithmetic. It writes formulas, and cfo.ai's calculation engine computes every number from them. That is why you can check a result: open the cell's formula, follow its inputs, and see the data they read. Other AI tools can work on the same Model too. An AI client such as Claude Code connects through the cfo.ai MCP server and uses the tools Ari uses to read and change the Model, under your account. It does not get Ari's own helpers, such as web search or file delivery. See [cfo.ai for AI agents](/agents.md). ## Data flows in from your systems Connected systems, such as QuickBooks, Xero, Gusto, or a Google Sheet, bring Actuals and operating data into the Model, and refresh once a day. An uploaded file is read once; to read a new version, replace it with **Update file**, or attach the new version with the same name in a chat and let Ari replace it after it asks. See [How connected data reaches your Model](/concepts/connected-data.md). ## Scenarios hold alternatives Main is your plan. A Scenario is a branch of the Model where you can try a different plan, such as a hiring freeze or a price change, without changing Main, and then compare the two or adopt the change. A Snapshot keeps a plan as it was at one moment, such as the budget your board approved. See [Scenarios, Snapshots, and version history](/concepts/scenarios.md). ## What this means in practice * Each Scenario has one version of each number. Fix it once, and every Page and chat in that Scenario sees the fix, as does every Scenario that reads the number from it. * You can always see why a number is what it is: its formula, its inputs, and where its data came from. * You choose how to work. Ask Ari, edit a table yourself, or do both on the same Page. ## Related * [Build your first Model](/tutorials/first-model.md) * [Variables and Dimensions](/concepts/variables-and-dimensions.md) * [The cfo.ai interface](/reference/interface.md) * [Glossary](/reference/glossary.md) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.