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

# Use Milvus storage

The `milvus` backend stores knowledge-chunk embeddings in a Milvus collection. It can connect to Milvus or Zilliz Cloud, or use a local Milvus Lite file. This backend is available in VeADK 1.0.3 and later.

## Dependencies

```bash lines theme={null}
pip install "veadk-python[extensions]"
```

## Use Milvus Lite

For local validation, point `DATABASE_MILVUS_URI` to a Milvus Lite data file and configure an embedding model:

```bash lines theme={null}
export DATABASE_MILVUS_URI="./data/product_docs.db"
export MODEL_EMBEDDING_API_KEY="your-ark-api-key"
```

The first run creates the data file. Later runs can retrieve existing content by using the same file and collection name.

## Example

```python lines theme={null}
from veadk import Agent
from veadk.knowledgebase import KnowledgeBase

kb = KnowledgeBase(
    backend="milvus",
    index="product_docs",
    backend_config={
        "index": "product_docs",
        "milvus_config": {
            "uri": "https://milvus.example.com",
            "token": "your-milvus-token",
            "db_name": "default",
        },
    },
)
kb.add_from_directory("./docs")

agent = Agent(knowledgebase=kb)
```

## Parameters

| Parameter | Type | Default | Description |
| - | - | - | - |
| `index` | `str` | None | Milvus collection name. It must start with a letter or underscore, contain only letters, digits, and underscores, and be at most 255 characters. |
| `milvus_config` | `MilvusConfig` | Read from `DATABASE_MILVUS_*` | Milvus connection and collection settings. |
| `embedding_config` | `EmbeddingModelConfig` | Read from `MODEL_EMBEDDING_*` | Embedding model used to vectorize knowledge chunks. |

### Milvus configuration

| Setting | Environment variable | Type | Default | Description |
| - | - | - | - | - |
| `uri` | `DATABASE_MILVUS_URI` | `str` | `""` | Remote Milvus URI or local Milvus Lite file path. Required. |
| `token` | `DATABASE_MILVUS_TOKEN` | `str` | `""` | Milvus token; takes precedence over username and password. |
| `user` | `DATABASE_MILVUS_USER` | `str` | `""` | Username, used with `password`. |
| `password` | `DATABASE_MILVUS_PASSWORD` | `str` | `""` | Password. |
| `db_name` | `DATABASE_MILVUS_DB_NAME` | `str` | `default` | Database name. |
| `overwrite` | `DATABASE_MILVUS_OVERWRITE` | `bool` | `false` | Whether to replace an existing collection during initialization. |
| `timeout` | `DATABASE_MILVUS_TIMEOUT` | `float \| None` | `None` | Request timeout in seconds. |
| `output_fields` | `DATABASE_MILVUS_OUTPUT_FIELDS` | `list[str] \| str` | Empty | Fields returned with search results; use a comma-separated value or JSON array in the environment variable. |

<Warning>
  Enabling `overwrite` can remove existing data from a collection with the same name. Use it only when the knowledge base can be rebuilt.
</Warning>