# Chassis

> Chassis is an embedded vector index for local semantic search: approximate nearest-neighbor search (HNSW) over embeddings kept in one file, inside your own process, with no server. Python: `pip install chassisdb`, `import chassisdb` (Python 3.11+). Rust: `cargo add chassisdb`. C: a library and `chassis.h` with each GitHub release.

Chassis stores vectors and integer ids only: keep text and metadata where the app keeps its data (SQLite, files) under the same id. An index's dimensions, metric, precision and `max_connections` are fixed when it is created and must be given again to reopen it. Adds and deletes are durable after `flush()`; closing or dropping an index without one discards them, as a crash would. One process writes a file at a time; readers take no lock, in any process, and see the last flush. Every error says what was wrong and, on a `help:` line, what to do.

## Docs

- [Everything below on one page](https://tanvincible.github.io/chassis/llms-full.txt): the guides, the Python, Rust and C references, the errors, and an example
- [Getting started](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/guide/getting-started.md): Rust, with pointers to Python and C
- [Python API](https://raw.githubusercontent.com/tanvincible/chassis/main/chassisdb/README.md): `VectorIndex`, `IndexOptions`, exceptions
- [Rust API](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/guide/api-reference.md): `VectorIndex`, `IndexReader`, `IndexOptions`
- [C API](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/guide/c-api.md): every `chassis_*` function
- [Errors](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/guide/errors.md): each kind, and what to do about it
- [Next to your database](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/guide/with-a-database.md): one id for both, the write order, what a crash leaves and how to mend it

## Integrations

- [LangChain](https://raw.githubusercontent.com/tanvincible/chassis/main/integrations/langchain-chassisdb/README.md): `pip install langchain-chassisdb`, a vector store with metadata filters and MMR
- [MCP memory server](https://raw.githubusercontent.com/tanvincible/chassis/main/chassisdb-mcp/README.md): `chassisdb-mcp`, long-term memory for coding agents

## Examples

- [Recipes](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/guide/recipes.md): search over notes, retrieval for a prompt, agent memory, "more like this", duplicates; each runs as written
- [Notes search](https://raw.githubusercontent.com/tanvincible/chassis/main/chassisdb/examples/notes_search.py): text in SQLite, vectors in Chassis, "more like this", deletes
- [Agent skill](https://raw.githubusercontent.com/tanvincible/chassis/main/plugins/chassis/skills/chassis/SKILL.md): the pattern and the rules, for coding agents

## Optional

- [How it works](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/architecture/overview.md)
- [Performance](https://raw.githubusercontent.com/tanvincible/chassis/main/docs/src/architecture/performance.md)
- [Changelog](https://raw.githubusercontent.com/tanvincible/chassis/main/CHANGELOG.md)