Smelt

Smelt is an open-source, Rust-based terminal AI coding agent developed by Leonard Cser. Designed for command-line developers, it provides an interactive terminal user interface (TUI) paired with an extensible runtime engine to assist with codebase navigation, code generation, and developer automation tasks. Operating directly in the terminal, Smelt features a responsive TUI that handles agent prompt execution, status monitoring, and background task animations. Under the hood, Smelt incorporates a dedicated runtime and a Lua scripting engine, enabling developers to interact with the agent interactively or orchestrate multi-step automated skills through custom scripts. Smelt distinguishes itself through its native Rust implementation, prioritizing low resource overhead, robust grapheme/unicode rendering in terminal emulators, and deep scriptability via a documented Lua API. This modular architecture allows developers to define custom agent behaviors and triage skills directly in repository configuration folders. Smelt is an open-source project distributed publicly on GitHub, free to clone, build, and adapt to custom development workflows.

Tags: ai agent, cli, coding agent, developer tools, terminal

Visit Smelt

Key features

• Rust-Native Core — Built as a high-performance modular Rust workspace with clean runtime separation and fuzz-tested stability. - Interactive Terminal UI — Delivers a terminal-native interface with smooth prompt rendering and real-time task progress feedback. - Lua Scripting Runtime — Provides a comprehensive Lua API and runtime engine to extend agent functionality and automate multi-step operations. - Modular Agent Skills — Supports custom agent skills organized within .agents/skills for domain-specific automation like fuzz triage. - Precise Unicode & Grapheme Handling — Tested to preserve complex graphemes and unicode formatting reliably across terminal input and output streams.

Use cases

Use Case: Interactive Terminal Development Developers working in terminal-first environments can launch Smelt to run interactive coding sessions, inspect repository contents, and execute code changes without leaving the command line.

Use Case: Custom Lua Workflow Automation Engineers can write custom Lua scripts using Smelt's Lua API to automate repository-specific maintenance tasks, code checks, or custom tool integrations.

Use Case: Automated Skill Execution and Triage Teams can configure predefined skills in the .agents/skills directory, enabling the agent to handle structured diagnostic workflows such as fuzz triage and test failure analysis.

Who it is for

Smelt is aimed at terminal-centric developers, Rust programmers, and automation engineers who require a lightweight, hackable CLI coding agent with Lua extensibility. It is not designed for users looking for GUI-bound IDE plugins or out-of-the-box closed-source SaaS integrations.

Install guide

Installation Smelt is built in Rust and can be installed from source using Cargo: bash # Clone the repository git clone https://github.com/leonardcser/smelt.git cd smelt # Build and install using Cargo cargo install --path crates/smelt

First Run Ensure that your terminal supports modern TUI rendering. Launch the application from within your target project repository: bash smelt If configuring custom skills or Lua extensions, ensure your .agents/skills/ definitions or .config settings are placed at the root of your workspace.

Example Session Launch Smelt in interactive mode within your repository to trigger code tasks: bash smelt # Within the Smelt TUI prompt: > Refactor the error handling in src/parser.rs to use custom error enums

Part of CLI Coding Agents

Categories: AI Coding Agents, Code Assistants, Developer Tools

Related CLI agents

• Warp — Warp is an AI-integrated terminal emulator and CLI workspace built by warpdotdev. Engineered in Rust with native GPU rendering, Warp…
• Amazon Q Developer CLI — Amazon Q Developer CLI is an open-source command-line coding assistant developed by Amazon Web Services (AWS). Built primarily in Rust,…
• CLAII — CLAII is an open-source terminal-based AI coding assistant developed by agencyswarm. Built in Python, it serves as a lightweight CLI…
• Even — Even is an agent-native desktop workspace and orchestration environment developed by Todience, Inc. It integrates a native terminal, an embedded…
• Repomon — Repomon is an open-source developer harness and repository companion tool created by Ali Hamza Azam. Built with a Rust core…
• Construct — Construct is an open-source terminal-based orchestrator and multi-harness manager developed by the construct-worlds organization. It functions as a meta-tool and…