> For the complete documentation index, see [llms.txt](https://developers.laws.africa/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.laws.africa/knowledge-bases/filters.md).

# Filters

Use filters to restrict which documents a Knowledge Base searches. Filters are most useful for legislation Knowledge Bases, especially provincial and municipal collections.

## Recommended legislation filters

For most legislation queries, start with:

```json
{
  "filters": {
    "principal": true,
    "repealed": false
  }
}
```

These filters exclude amendment or commencement works and repealed legislation.

## Place filters

Use `frbr_place` or `frbr_place__in` when you know the country, province, municipality or other locality you want to search.

```json
{
  "filters": {
    "frbr_place": "za-cpt"
  }
}
```

```json
{
  "filters": {
    "frbr_place__in": ["za-cpt", "za-jhb"]
  }
}
```

`frbr_place` is usually the safest place filter because it includes both the country and locality code.

## Other filters

The retrieve API also supports:

* `work_frbr_uri` and `work_frbr_uri__in`;
* `expression_frbr_uri` and `expression_frbr_uri__in`;
* `frbr_country`;
* `frbr_doctype` and `frbr_doctype__in`;
* `frbr_subtype` and `frbr_subtype__in`;
* `repealed`;
* `commenced`;
* `principal`.

Use exact filters only when your application already knows the relevant value. For exploratory search, start broad and then narrow the query.

## Example

```json
{
  "text": "informal trading permit",
  "top_k": 5,
  "filters": {
    "principal": true,
    "repealed": false,
    "frbr_place": "za-cpt"
  }
}
```

See the [retrieve endpoint reference](/knowledge-bases/reference/query-a-knowledge-base.md) for the full request schema.


---

# 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 dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://developers.laws.africa/knowledge-bases/filters.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.