# Expand your context

Choose the next business questions your context should answer. Add the knowledge they need while keeping your existing answers working.

## Choose a business area

Choose the next questions your team needs answered in the same business area. For example, a sales context could grow to cover product, category and country. List what would count as a correct answer, then use those questions to choose the tables and definitions to add.

Gather the relevant schema, dbt models, dashboard SQL and documentation. Before using new tables in Cassis, make sure they appear in its **Schema**: [update the DDL or sync the warehouse](/curate/data-source-changes/#when-the-warehouse-changes) as needed. You can prepare local additions from source exports before that step.

## Draft the additions

Use the context you already reviewed as the starting point.

In a git-managed project:

The [expansion skill](https://github.com/GetCassis/ontology-skills#expand-an-existing-ontology) guides a coding agent through the sources, proposed structure and changes. It works with schema and dbt exports; live warehouse access is optional.

For larger additions, the agent gathers evidence from your sources and compares the draft with a saved copy of your existing context. It sets up the local tools when needed. Focused edits use the evidence and checks already in your project.

Open your existing context repository and ask:

**Prompt for an agent: Expand a business area**

Prepares additions to your existing context for review.

```text
Use the ontology-expansion skill from GetCassis/ontology-skills, installing it if needed, to extend our context for <business area> and answer <new questions> from <source files>.
Agree the scope with me, then prepare and check the additions for review before publishing.
```

**Skill installation and validation commands**

```bash
npx skills add GetCassis/ontology-skills --skill ontology-expansion --full-depth
```

The agent handles the toolkit checkout and Python environment when needed; see the [local tooling guide](https://github.com/GetCassis/ontology-skills/blob/main/skills/ontology-expansion/references/local-tools.md). Local preparation and comparison do not require a Cassis account.

With a configured Cassis project and API key, refresh its schema and run the Cassis checks:

```bash
cassis schema pull
cassis context fmt
cassis context check
cassis context test -q "<a question to verify>"
```

After you approve the scope, test questions already covered as well as the new ones. If the repository has approved eval cases, use its [eval workflow](/curate/evals/). The skill’s [instructions](https://github.com/GetCassis/ontology-skills/blob/main/skills/ontology-expansion/SKILL.md) describe the complete process.

In an app-managed project:

Add the new tables from **Schema** using **Model with assistant**. Give the context Assistant the business area, questions and supporting sources. Ask it to propose the domain structure and additions while preserving the definitions you already reviewed.

Use a [Cassis branch](/curate/branches/) to test the expanded context before publishing. For a larger set of source files, you can [pull the existing context into a repository](/build/bootstrap/#pull-an-existing-context) and use the coding-agent path.

## Check both old and new answers

Review changes to existing definitions as carefully as additions. In particular, check shared filters, metric formulas and joins that could multiply rows. Resolve missing business decisions with the people who own them.

Try the new questions and a few answers you already trust. Compare the SQL and results using the same filters and dates. On a DDL project, run the SQL with your own tools; a structural check or an AI judgment of SQL does not establish the returned numbers.

## Publish the expanded context

Use the [publication step from your first context](/start/first-context/#3-publish-the-reviewed-context), or your team’s existing [Git](/curate/agent/) or [app](/curate/web-app/) workflow. Confirm the published version, then check the new coverage in fresh conversations.

As people use it, [analysis of chats with Cassis](/curate/issues/) helps identify further gaps. Repeat the expansion when another business area becomes useful.

**When to use the bootstrap kit**

The [bootstrap kit](https://github.com/GetCassis/ontology-skills#try-it-on-your-data) is for assembling a substantial initial context from existing assets. It produces a new tree for review. Use expansion for a context you already maintain; running the generator over it could erase reviewed definitions. See [Start a larger context](/build/bootstrap/#start-a-larger-context) if you are beginning from an empty project.