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

# Answer Modes: Chat & Agent

> Choose per question between a fast Chat answer and an autonomous, step-by-step Agent answer

## Introduction

On a Guru that has agentic capability enabled, each question can be answered in one of two modes, chosen with the `Chat | Agent` switch above the question box:

**Both modes can use your [Actions](/guides/actions) and [MCP tools](/guides/mcp-client) — the difference is *how*.**

* **Chat** (the default): a single grounded pass. Your Guru retrieves the relevant sources and, if a tool clearly matches the question, runs it once before answering. Fast, predictable, and inexpensive.
* **Agent**: an autonomous multi-step loop. The model decides which tools to call, can chain several across rounds, and reasons between them before answering. More capable for multi-step tasks, but slower and more expensive.

## Chat vs Agent

|                | **Chat** (default)                                      | **Agent**                                                              |
| -------------- | ------------------------------------------------------- | ---------------------------------------------------------------------- |
| How it answers | One grounded pass                                       | Autonomous multi-step loop                                             |
| Tools          | Runs a clearly-matching tool **once**, before answering | Model **picks and chains** tools across rounds, reasoning between them |
| Speed          | Fast                                                    | Slower (tools run before the first answer token)                       |
| Cost           | Low                                                     | Higher (each round re-sends the conversation and the tool schemas)     |
| Best for       | Most questions                                          | Multi-step tasks, live investigation, chaining several tools           |

## When to use which

* Reach for **Chat** for the large majority of questions: definitions, lookups, "what does the docs say about X", or a single action ("what's the current status of Y"). It is the fast, cheap default and it still uses a directly-relevant tool.
* Switch to **Agent** when the question is really a small task: "find the failing simulation, pull its latest run, and summarize the top threats", or anything that needs the Guru to gather data across several tools and reason over the results.

Agent mode is a per-question choice. Selecting it applies only to that question (and its follow-ups in the same chat); starting a new chat returns to Chat.

## Availability

The `Chat | Agent` switch appears only when a Guru is **agent-capable**: multi-step answering is enabled for the Guru **and** it has at least one usable tool (an enabled Action or a connected MCP server that exposes tools). Gurus without tools, or with multi-step answering off, always answer in Chat and show no switch.

Chat is always the default. Even on an agent-capable Guru, ordinary questions stay fast and cheap unless you explicitly pick Agent.

## Using it from the API

The `api/v1` answer endpoint accepts an optional `mode` field:

* `"chat"` (default) — single-pass answer.
* `"agent"` — the autonomous multi-step loop.

`agent` takes effect only on an agent-capable Guru (multi-step enabled + at least one tool); on any other Guru the request falls back to Chat.

```bash theme={null}
curl -X POST https://api.gurubase.io/api/v1/<guru-slug>/answer/ \
  -H "x-api-key: <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{"question": "Find the failing simulation and summarize its latest run.", "mode": "agent"}'
```

Omit `mode` (or send `"chat"`) for a normal fast answer.

<Note>
  Agent answers are slower and cost more than Chat answers, because the tool
  loop runs before the first answer token and each round re-sends the
  conversation plus the tool schemas. Use Agent when the task needs it; leave
  ordinary questions in Chat.
</Note>