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

# Custo

> Use matter-aware conversational AI in Ask or Agent mode.

**Custo**, **Generate**, and **Legal Agents** are three separate AI surfaces. This article covers **Custo** only.

Custo is matter-aware conversational AI. It reads your workspace context and can answer questions or take actions depending on the mode you select.

## Open Custo

* Press `Cmd+Shift+I` (Mac) or `Ctrl+Shift+I` (Windows) to open Custo
* Press `Cmd+Shift+S` (Mac) or `Ctrl+Shift+S` (Windows) to return to Studio
* Click **Ask Custo** on any matter or document page

## Ask mode vs Agent mode

**Ask mode** (Chat) is read-only. Custo retrieves, summarises, and answers questions. It does not create or modify anything.

**Agent mode** can create tasks, generate documents, run compliance checks, and take other actions. Agent mode is available on Learn and above. Agent mode asks for confirmation before any irreversible action.

<Note>
  Custo in Ask mode does not modify any data in your workspace. Switch to Agent mode when you want
  Custo to take action.
</Note>

## Attach context

Pin a matter or document to a thread so Custo answers in that context. Click the attachment icon in the composer and select the matter or document.

## Tool activity

When Custo runs a tool, an activity indicator appears showing the tool name (for example `list_matters`, `search_documents`). Expand the indicator to see query details and sources retrieved.

## Confirmation step

In Agent mode, Custo pauses before irreversible actions and shows a confirmation prompt. Review what Custo is about to do, then approve or cancel. Reply `yes` or `go ahead` to confirm. Reply `no` or `cancel` to abort.

## Thread history

Threads are stored per workspace in your browser. Open the thread list in the Custo panel to find previous conversations.

## Available models

| Model             | Description                                |
| ----------------- | ------------------------------------------ |
| Custo (default)   | Balanced routing across frontier models    |
| GPT-5             | Deep reasoning and multimodal intelligence |
| GPT-4o            | Real-time voice and vision                 |
| Claude 4 Sonnet   | Advanced agentic precision                 |
| Claude 3.7 Sonnet | Instruction following for legal workflows  |
| Gemini 3 Pro      | Large context windows                      |
| Gemini 3 Flash    | Fast multilingual responses                |

Change the model from the model selector in the Custo composer.

## Parity dock

The Parity dock is a lighter quick-assistant panel for short queries. It differs from the full Custo interface. Open it from the bottom-right dock icon on any product page.

<AccordionGroup>
  <Accordion title="Can Custo see all my matters?">
    Yes, in the workspace it is opened from. Custo searches matters, documents, and tasks within the
    active workspace.
  </Accordion>

  <Accordion title="Is my conversation stored?">
    Thread history is stored per workspace in your browser. Workspace admins can review activity
    through audit logs.
  </Accordion>

  <Accordion title="What is Custo?">
    Custo (also called Parity) is the default AI routing layer. It selects the most appropriate
    model for each query. Override it with a specific model if you prefer.
  </Accordion>
</AccordionGroup>

<CardGroup cols={2}>
  <Card title="Generate a document" icon="sparkles" href="/ai-and-generation/generating-a-document">
    AI-assisted drafting with verified citations.
  </Card>

  <Card title="Legal agents" icon="robot" href="/ai-and-generation/legal-agents">
    Autonomous background agents for Vertex and Zenith.
  </Card>
</CardGroup>