smelt

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Warning

smelt is in active development. main is mid-refactor, so code and docs are not fully in sync and some features are unfinished. Use the latest pre-release tag and update often. The last stable release is significantly behind and not recommended.

Why

Most coding agents are bloated and hard to customize. smelt is small, fast, and scriptable in Lua like Neovim. Built from scratch, with care for the details.

What's inside

• Terminal renderer. Its own grid and layout engine, not ratatui.
• Vim editor. Motions, text objects, registers, undo.
• Lua plugins. Keymaps, commands, autocmds, custom tools.
• Deterministic fuzzing. Fixed clock and stubbed I/O, so any crash can be replayed.
• No config needed. Run with flags, or smelt auth for ChatGPT and Copilot.

Install

Prebuilt binaries on the Releases page, or from source:

cargo install --git https://github.com/leonardcser/smelt.git

Upgrade

smelt checks for a new build hourly and shows a pill in the status bar when one's available. Run /upgrade to install — no confirmation dialog, just a notification: the install runs in the background, so you keep working while it happens; another notification fires when it's done and reminds you to restart. Overwriting an in-use binary is safe on Unix (the running process keeps its inode, future launches pick up the new one). /upgrade --check forces a fresh poll without installing; /changelog opens the release notes for the cached latest build; /version shows the running build identity.

smelt --version prints the same string surfaced by /version, shaped {tag}-{commits}-g{sha}[-dirty] (e.g. 0.5.0-alpha.2-80-g827e6646) so bug reports always pin down the exact source commit.

Two channels controlled by smelt.settings.autoupgrade_channel:

• "stable" (default) — latest tagged release, including alpha/beta prereleases. Installs by downloading the prebuilt tarball from GitHub Releases (seconds; no toolchain required).
• "unstable" — latest commit on the main branch. Installs via cargo install --branch main (a few minutes; requires cargo).

The polling behaviour is smelt.settings.autoupgrade: "off", "notify" (default, show pill but don't install), or "auto" (install in the background as soon as an update is detected). The poll cadence is smelt.settings.autoupgrade_interval (seconds, default 3600, floored at 60).

Run

API key providers (any OpenAI-compatible endpoint):

# local model via Ollama
smelt --model qwen3.5:0.8b --api-base http://localhost:11434/v1

# OpenAI, Anthropic, OpenRouter, etc.
smelt --model gpt-5.5 --api-base https://api.openai.com/v1 --api-key-env OPENAI_API_KEY

Subscription providers (ChatGPT Pro/Plus, GitHub Copilot):

smelt auth                          # one-time login
smelt --model gpt-5.4               # Codex
smelt --model claude-sonnet-4-6     # Copilot

Or just run smelt with no arguments and follow the wizard.

Docs

Full documentation for configuration, Lua API, keybindings, permissions, providers, and plugin authoring lives at leonardcser.github.io/smelt.

License

MIT, see LICENSE. Inspired by Claude Code and Neovim.