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

# Key Concepts and Vocabulary

> The shared vocabulary every prompt and design discussion relies on: blocks, inputs, variables, Knowledge Sources, and routing

Every prompt and every design discussion uses these terms. Define them once and use them consistently across inputs, prompts, and documentation.

## Vocabulary

| Term                      | Definition                                                                                                                                                |
| ------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Block**                 | One processing unit with one objective = one run of the Mainframe over its prompt and Knowledge Sources. Produces a text output.                          |
| **User Inputs**           | What the end user provides at runtime: Free Text, Multiple Choice, or Document Upload.                                                                    |
| **Variable**              | Written `/variable_name`. The full text of an input or upstream output, injected directly into a prompt ("inline").                                       |
| **Knowledge Source (KS)** | A document collection, or the web, searched via retrieval. The block retrieves relevant extracts instead of seeing the full text.                         |
| **Brain**                 | A pre-loaded, stable dataset attached by the App designer (for example, a methodology guide or a product catalog). Always accessed as a Knowledge Source. |
| **Inline routing**        | The full text lands inside the prompt. Used for short, targeted content.                                                                                  |
| **KS routing**            | Content is stored and searched; only relevant extracts are retrieved. Used for long content.                                                              |
| **Role**                  | The first line of every prompt: "You are a \[specific expert]...". Sets expertise, vocabulary, and judgment.                                              |
| **Context**               | The prompt section that states the role and the business frame of the task.                                                                               |
| **Tasks**                 | Numbered, verb-first instructions. One action per line.                                                                                                   |
| **Output format**         | The exact structure of the deliverable: headers, table columns, section order.                                                                            |
| **Constraints**           | Optional rules: terminology, scope, length, language.                                                                                                     |
| **Inputs**                | The closing section of a prompt listing every inline `/variable` the block receives. Knowledge Sources are never listed here.                             |
| **Hidden block**          | A block whose output feeds another block but is not shown to the end user (for example, an intermediate summary).                                         |
| **Sequential / parallel** | Blocks run one after another (sequential) or simultaneously (parallel).                                                                                   |
| **Conditional (IF/THEN)** | A block runs only when a condition on an input or upstream output is met.                                                                                 |
| **Review step**           | A block flagged as a checkpoint: the run pauses there for a person to review (and edit) the output before downstream blocks continue.                     |
| **Linked slide**          | A slide generated from a block's output and kept linked to it, built on the firm's slide template; regenerating the block refreshes the slide.            |

## Next

<CardGroup cols={1}>
  <Card title="Collecting User Inputs" icon="keyboard" href="/apps-academy/user-inputs">
    The three input types, their mandatory routing, and the rules that keep inputs clean.
  </Card>
</CardGroup>