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

# What are Functions?

Functions are actions that let a CallKaro AI agent do more than just talk. They help the agent fetch data, take actions during the call, and save outcomes after the call.

Functions are grouped by when they run:

1. **Pre-Call Functions** — run before the call.
2. **In-Call Functions** — run during the call.
3. **Post-Call Functions** — run after the call.

<Info>
  Functions that authenticate with another service should use a saved [secret reference](/agents/configurations/secrets), such as `x_secrets.CRM_API_KEY`, instead of a hardcoded credential.
</Info>

Let us go through each one.