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

# ThinkFeel Emotion AI API

> Build AI replies with custom personas.

<img className="rounded-xl" src="https://mintcdn.com/curvelabs/BiyQ4TsT2qUFcIh1/images/thinkfeel-opengraph.png?fit=max&auto=format&n=BiyQ4TsT2qUFcIh1&q=85&s=449757479deb342734a1418fb5755d91" alt="ThinkFeel by Curve Labs" width="2710" height="852" data-path="images/thinkfeel-opengraph.png" />

Use ThinkFeel to generate replies for a custom persona. Send the messages you want the persona to consider, and receive a response your product can show or adapt.

<CardGroup cols={2}>
  <Card title="Emotionally intelligent" icon="heart-pulse">
    AI that understands context, tone, and emotional subtext.
  </Card>

  <Card title="Custom personas" icon="user-gear">
    Work with Curve Labs to craft a persona tailored to your use case.
  </Card>

  <Card title="Stateless API" icon="diagram-project">
    Keep full control over conversation history and context.
  </Card>

  <Card title="Transparent pricing" icon="dollar-sign">
    Pay pricing close to model costs during the early access beta.
  </Card>
</CardGroup>

## Install the tools

```bash theme={null}
codex plugin marketplace add artificial-affect/thinkfeel-codex-dev-plugin
codex plugin add thinkfeel-codex-dev-plugin@thinkfeel
```

Most Codex users should add the ThinkFeel marketplace and install the plugin. Start a new Codex thread after installation so Codex loads the ThinkFeel plugin skill and MCP server.

```bash theme={null}
npm i @curvelabs.org/thinkfeel
```

<Info>
  The ThinkFeel SDK and CLI use the site origin for `THINKFEEL_BASE_URL`, such as `https://playground.curvelabs.org`.
  OpenAI-compatible clients use `https://playground.curvelabs.org/api/v1`.
</Info>

## Where to start

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Request access, set up keys, and send your first ThinkFeel request.
  </Card>

  <Card title="Authentication" icon="key" href="/authentication">
    Learn supported API key headers, environment variables, and security rules.
  </Card>

  <Card title="API reference" icon="code" href="/api-reference/generate">
    Review request and response details for each endpoint.
  </Card>

  <Card title="Cookbooks" icon="book-open" href="/cookbooks">
    Start from working example projects.
  </Card>
</CardGroup>

## Version

ThinkFeel API documentation version: `0.1.3 Beta`

Last updated: July 3, 2026