Holt

A native desktop coding agent built with Rust and GPUI.

Holt — transcript alongside a branch-changes diff

[!WARNING]
Holt is a work in progress — an experimental project under active
development. Expect rough edges and breaking changes.

Why Holt

Why not.

Holt is the agent. Model services plug in as providers; local coding-agent
CLIs are not interchangeable runtimes. One coherent agent loop drives every
chat. No cloud. No accounts, no sync, no telemetry. Chats, transcripts, and
credentials live under ~/.holt and nowhere else. No daemon, no CLI. A headed
desktop app that embeds its backend in-process over a typed memory-RPC
transport.

Quick start

cargo run --release -p holt

Then open Settings → Providers and add an API key before starting a run.

Data lives under ~/.holt; override with HOLT_DATA_DIR.

Architecture

gpui UI ── in-memory RPC (ndjson envelopes) ── LocalEngine + core agent loop

The UI never links backend logic. It talks the typed contract in crates/rpc;
crates/engine adapts pi-core-rs
behind the RpcService trait, so another backend can slot in without touching
the UI.

Crate	Role
`apps/holt`	The binary. No CLI.
`crates/ui`	The gpui viewport — agent-agnostic, renders `MessagePart`s from `holt-doc`.
`crates/engine`	The backend adapter: agent loop, providers, credentials, git, skills, terminals.
`crates/rpc`	The typed control plane: framing, dispatch, memory transport.
`crates/proto`	Shared protocol and domain types.
`crates/doc`	Loro-CRDT session docs and transcript types.
`crates/theme`, `crates/syntax`	Theme library and syntax highlighting.

See ARCHITECTURE.md for the full RPC contract and the design
decisions behind it.

Development

cargo check --workspace
cargo clippy --workspace
cargo fmt --all
cargo test --workspace

Contributing

See CONTRIBUTING.md — and please follow the
Code of Conduct. Found a security issue? Report it
privately via SECURITY.md.

Credits

The beautiful UI comes from comet ❤️