> This page location: Docs > Reference > Models > Create a Model
> Full index for agents: https://www.semantius.com/llms.txt

# Create a Model

> Build a custom semantic model from scratch with the Business Analyst agent skill.

- **URL**: https://www.semantius.com/docs/models/create

---

The `/semantic-model-analyst` [agent skill](https://www.semantius.com/docs/agent-skills.md) builds a [semantic model](https://www.semantius.com/docs/models.md) with you, the way a senior analyst would: interview, propose, confirm, write. The output is a single self-contained markdown file describing entities, fields, and relationships, ready for the [Deploy](https://www.semantius.com/docs/models/deploy.md) step.

## When to Use It

Trigger this skill whenever you need a data-backed system of any kind: a CRM, a helpdesk, an HRIS, a custom internal tool, or anything you would otherwise spec on a whiteboard. The skill handles greenfield modeling, mirroring well-known SaaS schemas (Salesforce, Zendesk, ServiceNow, HubSpot, Jira, and others), and reviewing or extending models that already exist.

## Create a New Model

Tell the skill what you want to model. Be as terse or as detailed as you like, the skill asks follow-up questions:

```text
/semantic-model-analyst I need a CRM for a 50-person SaaS sales team
```

```text
/semantic-model-analyst spec out a helpdesk for an internal IT department
```

```text
/semantic-model-analyst design a model for tracking field service jobs and technician schedules
```

## How a Session Goes

1. **Capture the system.** The skill asks what you want to model and pulls the domain category (CRM, ITSM, HRIS, ERP, and so on) from the conversation.
2. **Pick a naming style.** For well-known categories, you choose between an **agent-optimized** schema (self-describing names that LLMs can reason about) or a **vendor-template** schema (mirrors a specific incumbent, makes data migration trivial).
3. **Confirm the entity list.** The skill drafts 6 to 15 entities with one-line purposes. You add, rename, merge, or drop any of them.
4. **Confirm the fields.** For each entity the skill proposes a field table (name, format, required, label, references). You iterate until it matches the domain.
5. **Save the model.** The skill writes a `*-semantic-model.md` file with the right front-matter, an entity-relationship diagram in Mermaid, an enumerations section, and implementation notes.

The output file is portable. Pass it to the [Deploy](https://www.semantius.com/docs/models/deploy.md) skill to ship it to a live Semantius instance, hand it to a teammate for review, or run [Optimize](https://www.semantius.com/docs/models/optimize.md) later to pull a freshly-edited live module back into a markdown spec.

## Customize or Extend an Existing Model

The same skill audits a model file (flagging blockers, warnings, and suggestions against the Semantius platform constraints) and extends it (adding entities, fields, or relationships without breaking what is already there). Point it at any `*-semantic-model.md`, including one of the [Templates](https://www.semantius.com/docs/models/templates.md) you pulled down:

```text
/semantic-model-analyst customize ./crm-semantic-model.md, I want to drop campaigns and add a renewals entity
```

```text
/semantic-model-analyst customize https://www.semantius.com/models/saas_expense_tracker-semantic-model.md
```

```text
/semantic-model-analyst audit ./helpdesk-semantic-model.md
```

```text
/semantic-model-analyst extend ./hris-semantic-model.md with a time-off tracker
```

## Get the Skill

Install the Semantius CLI and the [agent skills](https://www.semantius.com/docs/agent-skills.md) bundle to add this skill to your agent.

[Install the Agent Skills →](https://www.semantius.com/docs/agent-skills/installation.md)

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## Related

- [Structure](https://www.semantius.com/docs/models/structure.md)
- [Templates](https://www.semantius.com/docs/models/templates.md)
- [Docs home](https://www.semantius.com/docs.md)
- [Full index for agents](https://www.semantius.com/llms.txt)