> ## Documentation Index
> Fetch the complete documentation index at: https://docs.correl8.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Custom integrations that use the Correl8 REST API

The REST API is available if you need a **custom integration** that cannot use MCP.

If you are building an AI agent, start with [MCP](/essentials/mcp) instead.

## Endpoints

| Method | Path                                                            | Purpose                                                                |
| ------ | --------------------------------------------------------------- | ---------------------------------------------------------------------- |
| `GET`  | `/v1/project/{project_id}/correl8-guidelines/`                  | Load guidelines (same as MCP tool `get_correl8_guidelines`)            |
| `GET`  | `/v1/project/{project_id}/research/studies/`                    | Load active studies for a user (same as MCP tool `get_active_studies`) |
| `POST` | `/v1/project/{project_id}/observations/`                        | Create one or more observations                                        |
| `POST` | `/v1/project/{project_id}/research/studies/{study_id}/answers/` | Post a research study answer                                           |

All endpoints use `Authorization: ApiKey c8.xxx` (or `X-Api-Key`).

## Documentation

<Columns cols={2}>
  <Card title="Get guidelines" icon="book-open" color="hsl(220, 10%, 35%)" href="/essentials/guidelines-ingestion">
    Fetch observation and research guidelines via REST.
  </Card>

  <Card title="Get active studies" icon="flask-conical" color="hsl(280, 70%, 51%)" href="/essentials/active-studies-ingestion">
    Fetch active research studies and logged answers for a user.
  </Card>

  <Card title="Post observations" icon="upload" color="hsl(160, 62%, 37%)" href="/essentials/observations-ingestion">
    Narrative guide with curl examples.
  </Card>

  <Card title="Post a study answer" icon="message-square" color="hsl(40, 90%, 42%)" href="/essentials/research-answer-ingestion">
    Post one research answer per user per study.
  </Card>

  <Card title="API reference" icon="code" color="hsl(280, 70%, 51%)" href="/api-reference/introduction">
    Schemas, auth, and auto-generated endpoint docs.
  </Card>
</Columns>