Topic filters for request gating
Key Takeaway
A filter hides a subagent or action from the LLM until its variable condition, such as Verified equals True, is met. Until then, the agent can't use it, and the Agent Router leaves a filtered subagent out of its choices.
A filter is a condition, built on agent variables, that controls whether an agent can use a subagent or an action in a conversation. Beginning in April 2026, agent topics are called subagents, with no change in functionality, so a topic filter is a filter applied to a subagent. Filters exist because instructions to the LLM are not deterministic. Until the condition is true, a filter hides the subagent or action from the LLM entirely.
What a filter applies to
You can apply a filter to a whole subagent or to a single action inside a subagent. The agent can use that subagent or action only when the filter's conditions are met.
A filter on an action applies the same idea at a finer level. For example, a create_return action can be available only when order_return_eligible == True and order_id != None. The LLM then never sees a return option for an ineligible order.
A filter applies only within the agent where you apply it. Inside that agent, you can reuse one filter on several subagents or actions. You can also view every asset that currently uses the filter.