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Preconditions and Postconditions

Preconditions declare what state MUST be true before an operation can execute. Postconditions declare what state WILL be true after successful execution.

Preconditions​

Examples:

  • cart_validated — The cart must be validated before checkout
  • user_authenticated — The user must be logged in
  • inventory_reserved — Inventory must be reserved before payment

Preconditions enable agents to:

  1. Check whether execution is safe before invoking
  2. Identify what steps must be completed first
  3. Plan multi-step workflows automatically

Postconditions​

Examples:

  • checkout_session_created — A checkout session will exist after execution
  • ticket_assigned — The ticket will be assigned to an agent
  • order_confirmed — The order will be in confirmed status

Postconditions enable agents to:

  1. Verify operation success
  2. Chain operations by using postconditions as preconditions for subsequent steps
  3. Report expected outcomes to users

Workflow Chaining​

Preconditions and postconditions enable automatic workflow planning:

validate_cart → postcondition: cart_validated
reserve_inventory → precondition: cart_validated → postcondition: inventory_reserved
begin_checkout → precondition: cart_validated, inventory_reserved → postcondition: checkout_session_created

An agent can automatically determine the correct execution order.

Next Steps​