Memory Variables

Note

Memory variables are a feature in agent templates (part of Letta Cloud). To use memory variables, you must be using an agent template, not an agent.

Memory variables allow you to dynamically define parts of your agent memory at the time of agent creation (when a template is used to create a new agent).

Defining variables in memory blocks

To use memory variables in your agent templates, you can define variables in your memory blocks by wrapping them in {{ }}. For example, if you have an agent template called customer-service-template designed to handle customer support issues, you might have a block of memory that stores information about the user:

The user is contacting me to resolve a customer support issue. Their name is
{{name}}
and the ticket number for this request is
{{ticket}}.

Once variables have been defined inside of your memory block, they will dynamically appear at variables in the ADE variables window (click the ”{} Variables” button at the top of the chat window to expand the dropdown).

Simulating variable values in the ADE

Tip

Reset the state of the simulated agent by clicking the “Flush Simulation” 🔄 button.

While designing agent templates in the ADE, you can interact with a simulated agent. The ADE variables window allows you to specify the values of the variables for the simulated agent.

You can see the current state of the simulated agent’s memory by clicking the “Simulated” tab in the “Core Memory” panel in the ADE. If you’re using memory variables and do not specify values for the variables in the ADE variables window, the simulated agent will use empty values.

In this prior example, the name and ticket variables are memory variables that we will specify when we create a new agent - information that we expect to have available at that time. While designing the agent template, we will likely want to experiment with different values for these variables to make sure that the agent is behaving as expected. For example, if we change the name of the user from “Alice” to “Bob”, the simulated agent should respond accordingly.

Defining variables during agent creation

When we’re ready to create an agent from our template, we can specify the values for the variables using the variables parameter in the create agents from template endpoint:

curl -X POST https://app.letta.com/v1/templates/{project_slug}/{template_name}:{template_version} \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -d '{
    "from_template": customer-service-template:latest",
    "variables": {
      "name": "Bob",
      "ticket": "TX-123"
    }
  }'