# Agents: Variables (https://docs.envocal.ai/agents/variables/)

> Make the Agent dynamic & context-aware

## Variables in the instructions
Variables allow you to **pass dynamic, real-time data into the Agent’s Instructions**.

👉 They are evaluated at runtime and injected into the Instructions, giving the Agent access to realtime, relevant information.

Having in mind that the values need to be known at runtime -  **Dynamic** and **System** variables can be used.

Dynamic variables populated at runtime, usually come from tool responses, external systems or backend logic (hooks).
When configuring a tool that will be called before conversation and whose result is used as variable within the Agent's Instructions, it is important to **map the reponse**.
Esentially, this is storing the results value in a variable that is then be evaluated at runtime. 

In our example, **datetime** variable comes as result from tool **Get Current Time** called before the conversation and whose response is mapped to this variable. 

![AgemtVariables](https://docs.envocal.ai/img/Agent/Vars.PNG)

Within the Instructions, the variable is used as "Current DateTime is: \{ \{ datetime\} \}"

[Check out how Get Current Time is configured](/tools/examples#get-current-time)

## Related topics

- [Creating a Custom Tool](https://docs.envocal.ai/tools/tools/)
- [Complete Examples](https://docs.envocal.ai/tools/examples/)
- [Basic Setup](https://docs.envocal.ai/agents/basic/)