Rule Trees and Post-Response Actions

The Rules and Actions tabs turn a static response into a stateful branch in a larger workflow.

Rule Trees

A rule tree decides whether a response matches the current request.

Each rule tree starts at a root node and can contain:

• logic groups with AND or OR
• simple predicates
• custom Python predicates

What simple predicates check

Simple predicates compare an actual value from the request or state against an operator and, when needed, an expected value.

Common examples:

• {{request.headers.authorization}} does not equal {{constants.auth_token}}
• {{request.body.value.model}} is an empty string
• {{request.body.value.temperature}} is greater than 2

When to use custom Python predicates

Use a Python predicate when the condition depends on logic that is awkward to express as a single comparison.

The seeded projects use custom predicates for cases such as:

• checking whether a requested blog post ID exists in globals.posts
• validating a request body against several business rules at once

Post-response actions

A post-response action runs after the response has already been returned to the client. This is the mutation layer of the platform.

Available action types are:

• set
• unset
• increment
• decrement
• append
• remove
• script

The first six handle direct variable updates. The script action lets Python compute one or more actions dynamically.

What actions are for

Actions are how you model stateful workflows:

• create a record after a 201
• update a shared object after a 200
• increment counters after a successful request
• remove data after a delete flow

In the seeded Create Post example, the Post Created response returns 201 immediately and then:

1. writes the new post into globals.posts
2. increments globals.next_id
3. increments globals.total_posts

That is why the next request sees different project state even though the response itself is just a JSON payload.

Rules versus actions

Keep the split clear:

• Rules decide whether this response should be selected
• Actions mutate state after that response is selected

If a condition should block the response, it belongs in Rules. If state should change because the response already happened, it belongs in Actions.