---
title: DataHub NATS topics
slug: litmus-mcp-server/datahub-nats-topics
docTags: 
createdAt: 2026-05-11T21:50:14.924Z
---

# NATS Topics

Read live values published to Litmus Edge's internal NATS broker.

| Tool                                 | Description                                                              |
| ------------------------------------ | ------------------------------------------------------------------------ |
| `get_current_value_from_topic` `*`   | Subscribe to a NATS topic and return the next published message.         |
| `get_multiple_values_from_topic` `*` | Collect multiple sequential values from a NATS topic for trend analysis. |

## When to use which

- **Spot read:** `get_current_value_from_topic` for the next message on a topic. Useful when DeviceHub publishes tag values you want to inspect without persisting them.
- **Short window of samples:** `get_multiple_values_from_topic` to collect N consecutive messages for a quick trend check. For longer or historical windows, use [InfluxDB / Time Series](#) tools instead.

Both tools open a NATS subscription, wait for messages, then drain and close cleanly.

## Requirements

- `NATS_SOURCE`, `NATS_PORT`, `NATS_USER`, `NATS_PASSWORD` headers.
- `NATS_TLS` defaults to `true`; set to `false` if your broker is non-TLS.

## Setting up NATS access on Litmus Edge

1. Navigate to **Litmus Edge -> System -> Access Control -> Tokens**.
2. Create or configure an access token with permissions for the topics you want to read.
3. Provide the token username and value as `NATS_USER` / `NATS_PASSWORD` in your MCP client configuration.

## Related

- [DeviceHub, Tags](#) - the tag output topic is what these tools subscribe to.
- [InfluxDB / Time Series](#) for historical analysis.