LoCode

A Rust-based custom coding agent: the sample → dispatch → append loop, a typed tool registry, faithful per-harness tool packs, and a provider/wire abstraction — shipped as a set of library crates plus the locode binary (run locode -p "say hi" for a headless rollout, or locode without -p for an experimental interactive TUI).

Why

LoCode is a distilled re-implementation of the agent cores of four studied coding harnesses (Claude Code, Codex, Grok Build, opencode). Each harness pack reproduces its harness's real tools and system prompt — names, schemas, caps, quirks — so different harness designs can be compared honestly, A/B, on the same engine and the same provider wire. The tool packs are also a first-class library surface: downstream consumers can drop the tools into their own agent loop without using our engine.

The reproduction is deliberately scoped. What each pack faithfully mirrors is its harness's system prompt and its tool behavior — and the tool surface is the six core tools every coding agent shares (shell, read, write, edit, list, search). Everything above that line — memory files (AGENTS.md and friends), skills, and the fancier engine behaviors — is implemented once and shared across all packs rather than reproduced per harness, so the fancier per-harness features are not modeled. That core is enough to run most coding-benchmark evaluations and everyday tasks, but it is not exhaustive: LoCode is built for evaluation and research, not as an end-user product.

Install

Prebuilt locode binaries for macOS and Linux (one command to install, re-run it to update):

curl -fsSL https://raw.githubusercontent.com/luolc/locode-core/main/install.sh | bash

The script installs to ~/.locode/bin (override with LOCODE_BIN_DIR), verifies the sha256 checksum, and puts the binary on your PATH. Pass a version for a specific release: … | bash -s 0.1.10. Then run locode for the interactive agent or locode -p "task" for a headless one-shot. The search tools shell out to ripgrep — have rg on PATH or point LOCODE_RG_PATH at a binary.

Or build from source: cargo install --git https://github.com/Luolc/locode-core locode-app.

Quick start

export LOCODE_API_KEY=…      # required (except with --api-schema mock)
export LOCODE_BASE_URL=…     # optional: provider endpoint override
export LOCODE_MODEL=…        # optional: model id override

# One task, headless: one JSON report on stdout, diagnostics on stderr.
locode -p "summarize this repo" --harness grok
# …or from a source checkout, without installing:
cargo run -p locode-app -- -p "summarize this repo" --harness grok

Select the provider wire with --api-schema (anthropic | openai-responses | mock, where mock runs keyless) and the stdout artifact with --output-format (json | stream-json | text). See locode --help for the full surface.

LOCODE_BASE_URL defaults to the wire's native endpoint (https://api.anthropic.com for anthropic, https://api.openai.com for openai-responses); point it at any compatible gateway (e.g. OpenRouter) to reach other providers over the same schema. LOCODE_API_KEY must match whichever endpoint you target.

Interactive app (`locode`)

LoCode is primarily a headless engine for evaluation and data pipelines. It also ships an experimental interactive terminal UI, built in this repo as separate crates (locode-tui = components/library, locode-app = the locode binary) layered on the core (ADR-0019). It drives one session interactively: type a prompt, watch tool calls and the reply stream in, approve or deny tool calls, cancel a turn with Esc, and continue the conversation. Treat it as a convenience for exploring the engine, not a supported product.

# Keyless demo (scripted mock wire — no API key):
locode --api-schema mock

# Against a real wire, with tool approvals prompted:
LOCODE_API_KEY=… locode

# …or skip approvals (auto-allow every tool, lift the path jail):
LOCODE_API_KEY=… locode --yolo

Development

To build and test everything:

cargo fmt --all -- --check
cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspace
RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps

Custom providers

The provider surface is open: implement the Provider trait for any backend, register it under a name, and your own binary crate gets the entire CLI — flags, report envelope, exit codes — with your provider selectable at run time:

use locode_exec::{ProviderRegistry, main_with};

fn main() -> std::process::ExitCode {
    let registry = ProviderRegistry::builtin()
        .register("my-wire", |init| my_wire::build(init));
    main_with(registry)
}

--api-schema my-wire then selects it; unknown names fail before the run starts, listing what's registered.

Disclaimer

This is a personal project and is not affiliated with any company. The content does not reflect any specific company's projects, products or internal work.

locode-host 0.1.10