rasa-managing-slots

Managing Slots in Rasa

Workflow

1. Identify what information the assistant needs to remember.
2. Review existing slots in the domain — reuse before creating new ones.
3. Choose the most restrictive slot type that fits the data (see "Choosing a slot type").
4. Define the slot in the domain file with type and mapping (see "Slot mappings").
5. Set an initial_value if the slot needs a default.
6. Add validation if the slot requires format or range checks (see "Validation strategies").
7. Use the slot in flows via collect or set_slots steps.

File organization

Slots are defined in domain YAML files, typically under domain/ or in a single domain.yml. Before creating new slots, check the existing domain layout — the user's existing convention always takes precedence.

Domain files are commonly split by business process, so each flow's slots, responses, and actions live together (e.g. domain/transfer_money.yml).

domain/
├── transfer_money.yml  # slots + responses + actions for one flow
├── book_appointment.yml
└── shared.yml          # slots reused across multiple flows

Choosing a slot type

Pick the most restrictive type that fits the data. This prevents invalid values and helps the LLM within the Command Generator extract correctly.

Type	Use when	Example
text	Any string value	names, emails, free-text input
bool	Binary yes/no	is_authenticated, terms_accepted
categorical	Value must come from a fixed set (auto-coerces casing)	account types, priority levels
float	Numeric value with decimals	temperature, amounts, scores
any	Structured data (dicts, mixed types)	API responses, shopping carts
list	List of values (custom actions only)	item lists — cannot be filled via collect or set_slots

slots:
  patient_name:
    type: text

  terms_accepted:
    type: bool

  priority:
    type: categorical
    values:
      - low
      - medium
      - high

  temperature:
    type: float

  search_results:
    type: any