> ## Documentation Index
> Fetch the complete documentation index at: https://mux.coder.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Automatic Compaction

> Let Mux automatically compact your conversations based on usage or idle time

Mux can run `/compact` for you to keep context size manageable. There are two types of automatic compaction:

* **Usage-based**: Compacts when your conversation reaches a configurable percentage of the model's context window
* **Idle-based**: Optionally compacts inactive workspaces after a period of time

## Usage-based auto-compaction

When enabled, Mux monitors your context usage and:

1. Shows a subtle warning as you approach the threshold (e.g., "Auto-Compact in 12% usage")
2. When you send your next message **at or above the threshold**, Mux runs compaction first, then automatically sends your message as a follow-up

### Configure the threshold

* Open the **Costs** sidebar tab and find **Context Usage**
* Drag the blue marker to set the percentage
* The setting is **saved per model** (and applies to any workspace using that model)
* Default is **70%**
* Set it to **100%** to disable usage-based auto-compaction

Mux caps the enabled threshold at **90%** to leave a safety buffer before hard context limits.

### Force-compaction during streaming

If a single response pushes context usage above your threshold while streaming, Mux may interrupt and compact automatically once you exceed the threshold by an additional buffer (currently **+5%**). After compaction, Mux resumes the conversation automatically.

This safety mechanism prevents hitting hard context limits mid-stream.

***

## Idle-based auto-compaction

Idle-based auto-compaction is **off by default**.

When enabled for a project, Mux periodically checks for workspaces that:

* Have been inactive for the configured number of hours
* Are not currently streaming
* Are not already compacted

Eligible workspaces are compacted automatically and marked with the idle-compacted badge (**💤📦**).

### Configure idle compaction

You can configure idle compaction via the UI or a slash command:

**Via UI:**

* Click the context usage indicator in the chat input toolbar
* Enable idle-based auto-compact and set the hours

**Via command:**

```
/idle <hours>
/idle off
```

Examples:

```
/idle 24
```

Compact workspaces after 24 hours of inactivity.

```
/idle off
```

Disable idle compaction for this project.

### Notes

* The setting is **per project** (applies to all workspaces in the project)
* Mux checks roughly **once per hour**, so compaction may not trigger immediately when the timer expires

***

## General notes

* Auto-compaction uses API tokens (same cost model as `/compact`)
* Auto-compaction requires known model context limits; if Mux can't determine a model's context window, usage-based auto-compaction won't run
* Both types of auto-compaction use the same summarization logic as manual `/compact`