kuangren chu

Posted on Apr 18

A declarative CLI framework in Rust

#showdev #rust #tooling #cli

I built a declarative CLI framework in Rust (define your CLI in TOML)

Most Rust CLI tools are built with libraries like clap. They’re powerful—but also verbose.

After building a few internal tools, I kept running into the same problem:

Too much boilerplate for simple commands
Repeating argument parsing logic
Hard to manage growing CLI complexity

So I built tkucli — a declarative CLI framework for Rust.

🧠 The idea

Instead of writing Rust code to define commands, you describe your CLI in a TOML file.

You define:

commands
arguments
workflows

…and the framework handles execution.

✨ Example

Define a command:

[app]
name           = "vm-cli"
version        = "0.1.0"
description    = "A Tkucli-powered CLI"
default_output = "table"

[tui]
enabled        = true
theme          = "dark"

[[resource]]
name        = "vm"
description = "VM resource — replace with your own"

  [[resource.operation]]
  verb        = "create"
  description = "create a vm"
  args        = [{ name = "name", type = "string", required = true }]

  [[resource.operation]]
  verb        = "list"
  description = "List all examples"
  flags       = [
    { name = "limit", short = "n", type = "u32", default = "20", help = "Max results" },
  ]

  [[resource.operation]]
  verb        = "get"
  description = "Get a vm by name"
  args        = [{ name = "name", type = "string", required = true }]

  [[resource.operation]]
  verb        = "delete"
  description = "Get a vm by name"
  args        = [{ name = "name", type = "string", required = true }]

Run it:

tkucli vm-cli vm create --name first-vm

🚀 Why I built this

I wanted something that feels like:

Infrastructure-as-Code, but for CLI
Easy to extend (TUI, workflows, automation)
Great for internal tools / DevOps / homelabs

🔄 How it compares

clap → full control, but code-heavy
bash → quick, but messy at scale
tkucli → structured, declarative, fast to build

🧩 Use cases

Wrapping tools like Ansible / Terraform
Internal developer platforms
Automation CLIs
Homelab management

⚠️ What it’s NOT

This isn’t trying to replace low-level CLI frameworks.

If you need:

very custom parsing
maximum performance → use clap

💡 What I’m exploring next

Built-in TUI support (ratatui-style)
Better workflow composition
Git-backed CLI configs

🙌 Looking for feedback

I’m trying to answer a simple question:

What if building a CLI felt like writing a config, not a program?

Curious if this resonates with others building tools in Rust.

Does this solve a real pain for you?
Would you use something like this?

Happy to share repo / details if there’s interest.

DEV Community