# O04: Automatic Prefix Caching

- Publisher: vLLM
- URL: [Primary source](https://docs.vllm.ai/en/latest/features/automatic_prefix_caching/)
- Published: not stated
- Updated/version date: 2026-10-13
- Accessed: 2026-10-22
- Type: official runtime documentation, rolling latest
- Verification: opened source, rather than relying on a search excerpt

## Supported finding

Shared-prefix KV reuse avoids repeated prefill. It does not reduce the decoding work needed to generate new tokens.

## Limits and transfer

Requires matching reusable prefixes. No financial saving is guaranteed for a fixed-capacity deployment.

## Use in the session

Mechanism and decision conditions. Retain the qualifications when translating the finding into slide copy. No source establishes Knauf's savings.