---
title: Environment variables
description: The environment variables Heed sets in its panes, and the ones it reads.
url: https://docs-v3-preview.elastic.dev/reference/environment
---

# Environment variables
## Set in every pane


| Variable          |                                                                                                                                |
|-------------------|--------------------------------------------------------------------------------------------------------------------------------|
| `HEED_SESSION_ID` | The session the pane belongs to                                                                                                |
| `HEED_SOCKET`     | The socket to report to                                                                                                        |
| `HEED_PANE_ID`    | The pane                                                                                                                       |
| `HEED_BIN`        | The bundled `heed` helper                                                                                                      |
| `PATH`            | The PATH Heed found (see [Finding git and gh](https://docs-v3-preview.elastic.dev/configuration/tools)), with the helper first |


## Read by Heed


| Variable          |                                                                                             |
|-------------------|---------------------------------------------------------------------------------------------|
| `XDG_CONFIG_HOME` | Where `heed/config.toml` lives, if set                                                      |
| `HEED_FIXTURE`    | Open on made-up data, with no IO: `main`, `empty`, `resume`, `firstrun`                     |
| `HEED_SNAPSHOT`   | Render the window to this PNG and quit (`HEED_SNAPSHOT_KEYS`, `_SIZE`, `_DELAY`, `_SETTLE`) |
| `HEED_SHOTS`      | Render every docs screenshot into this folder and quit (`HEED_SHOTS_ONLY`, `HEED_DOCS`)     |

The last three are for working on Heed itself: `mise run shots` uses `HEED_SHOTS` to regenerate every image in these
docs from the fake world.