Chevalier

Chevalier is the runtime toolkit behind agentic products that need more than a chat completion call. It is Rust-first, with TypeScript and Python bindings where they make sense.

It currently covers four product-grade surfaces:

• model/provider runtime and tool calling
• MCP clients, servers, and app resources
• sandboxed computers backed by local vmd or OpenComputer
• optimized VFS storage with local, object-store, packed, Postgres-indexed, and gateway modes

Packages

Path	Package	What lives there
rust/	chevalier	Rust LLM runtime, provider clients, tool schemas, streaming, MCP/VFS/sandbox feature hooks
ts/	chevalier	Node/Bun bindings for runtime, MCP, and VFS client APIs
ts-sandbox/	chevalier-sandbox	Separate Node sandbox binding so normal TS users do not pull in the heavier sandbox client
py/	chevalier	Python bindings via PyO3/maturin
mcp/	chevalier-mcp	Rust MCP client/server/apps library
sandbox/	chevalier-sandbox, vmd, portproxy	Sandbox facade, local host daemon, OpenComputer adapter, control-plane plumbing
vfs/	chevalier-vfs	Optimized VFS primitives: manifests, packed storage, batch reads/writes, gateway client/server contracts
durable/	chevalier-durable	Small durable execution vocabulary: run, step, state, effect, wait, event

More detail:

• Component map
• Sandbox and VFS integration
• Contributing and verification expectations

How The Pieces Fit

Chevalier keeps product code above the infrastructure boundary:

Product runtime
  -> chevalier / TS / Python runtime APIs
  -> MCP, sandbox, VFS, durable primitives
  -> provider APIs, vmd/OpenComputer, object stores, databases

The important rule is that product policy stays in the product. Chevalier provides reusable runtime machinery: tool loops, provider clients, sandbox sessions, VFS storage interfaces, command mounts, packed file storage, and gateway clients. Ownership, authorization, billing, audit, and domain-specific path rules wrap these packages.

Development

This repo uses Rust 2024 and the local .tool-versions rust stable toolchain. Run checks from the package you changed:

# Rust agent runtime
cd rust
cargo test --all-features
cargo clippy --all-features -- -D warnings

# Sandbox facade, vmd, and portproxy
cd sandbox
make verify

# VFS
cd vfs
cargo test --all-features
cargo clippy --all-features -- -D warnings

# TypeScript bindings
cd ts
npm test
npm run build

# TypeScript sandbox binding
cd ts-sandbox
npm run build

# Python bindings
cd py
maturin develop

Some gates require live providers or real sandbox machinery. Do not treat a narrow unit test as proof that a provider, VFS gateway, or sandbox backend works end-to-end.

License

Apache-2.0