> For the complete documentation index, see [llms.txt](https://docs.akenza.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.akenza.io/device-management/rule-engine/rule-input.md). # Input The devices, tags, or tag combinations whose data samples trigger a rule. The **input** of a rule defines which devices trigger its logic. Each time an input device sends a data sample to akenza, the linked logic block is evaluated with that sample.

The Select input type dialog with the options Device, Tag, and Tag combination — Selecting the input type

A rule can have one or more inputs of three kinds:

Input	Triggers the rule for
Device	One device. Any device can be selected, regardless of its connectivity.
Tag	Every device that has the tag assigned.
Tag combination	Every device that matches a logic expression of several tags.

The rule input section with a device search field and a list of selected devices — Selecting the input devices of a rule

Use the search field to find devices by name. A device can only be added once per rule, so devices that are already added cannot be selected again. {% hint style="info" %} All devices selected by a tag or tag combination should send data with the same schema. The logic block reads the same topic and data key from every device, so a device with a different schema cannot be evaluated. {% endhint %} {% hint style="warning" %} [Timed rules](/device-management/rule-engine/timed-rules.md) only support devices as input. A rule with a tag or tag combination input is aborted when its timer triggers it. {% endhint %} --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.akenza.io/device-management/rule-engine/rule-input.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.