# Index a collection

> Read every passage through the lens into cards, with the cost shown first and a limit you set.

Indexing is the step that costs money: each passage is sent to a model once, and each card is embedded for search.

## Before you start

- Model Hub is connected and has a provider.
- The collection exists: see [Make a collection](collections.md).
- For books, Calibre's Content Server is running. **Settings → Clusters → Setup** shows whether it is.

## Steps

1. Run **Clusters: Index a collection…** and pick the collection. Or open the collection on the **Collections** tab and select **Index…**.
2. Read the **dry run**: the documents and passages, any book without passages and why, what the run would read and embed, and the estimated cost. No model has been called and nothing is written. **How this run works**, under the fold, says what is read again and why, where the index lives, and opens **Preview passages…**.
3. Choose **Cheaper**, **Balanced** or **Better** for this run. Cheaper asks OpenRouter for its lowest-priced provider; Better reads passages one tier up and asks OpenRouter for its fastest. The provider sort acts only through OpenRouter: when the reading task's models don't go through it, Better's tier is what changes, and the dialog says so. Nothing in Models changes.
4. Optionally set a **spend limit**. The run stops when it reaches it. Model Hub's own limits and budgets apply as well.
5. Select **Index**. When the run ends, a short summary says what failed, what was read and embedded and what it cost; the full report is under **Full report**.

![The Index dialog before a run, with How this run works open and Preview passages… under it](img/index-dialog.png)

![The Index dialog when the run has ended: the summary and one Done button](img/index-done.png)

The job shows its progress and its cost so far. It warns when it has made no progress for five minutes. **Cancel** stops it; so does **Clusters: Open jobs**.

## What a later run does

- A run picks up where the last one stopped.
- A passage is read again only when what would be sent for it has changed: its text, or the lens.
- A book is split into passages once and they are kept. Notes are split again on each run, so new and changed notes are picked up.

## If a book needs converting

A book that has only an AZW3 or MOBI file needs an EPUB. By default Books & Shelves asks before it converts, and the conversion adds an EPUB to the book in your Calibre library. **Settings → Clusters → Setup → Convert AZW3 and MOBI books** set to *Never* skips those books instead; the dry run names them.

## Keep a collection up to date

In the collection's dialog, **Keep up to date** indexes what changes on its own: notes added, changed or removed in the folder or with the tag, a Base's rows, or a shelf whose members changed in Calibre (compared every half hour). It is off until you turn it on, since it spends money unasked. **Settings → Clusters → Setup → Keep up to date spends up to** caps what all automatic runs may spend in a day; at the cap they pause until tomorrow. Automatic runs never ask to convert a book, and show in Jobs with their cost like any run.

## Where the index is kept

In Clusters' plugin folder, inside your vault's configuration folder: `.obsidian/plugins/clusters/corpora/`. It holds the passages, cards, vectors and run logs. The **Collections** tab says how much each collection's index takes, on its row and in its dialog.

**Uninstalling Clusters deletes every index**, including the reading and vectors you paid for. Copy the `corpora` folder out first if you want to keep them. Your notes stay.

## Related

- [Search a collection](search.md)
- [Undo a run](undo-a-run.md)
- [Privacy and costs](privacy-and-costs.md)