Agent skill

Hare Lang

by mohitmishra786 in mohitmishra786/low-level-dev-skills

Hare language skill for simple systems programming. An agent skill from mohitmishra786/low-level-dev-skills.

MITAuto-check: notesDevelopment

Install Hare Lang

skills CLI

$ npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install mohitmishra786/low-level-dev-skills hare-lang --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/languages/hare-lang .claude/skills/hare-lang && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "hare-lang" agent skill from https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang into .claude/skills/hare-lang/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hare-lang", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install mohitmishra786/low-level-dev-skills hare-lang --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/languages/hare-lang .agents/skills/hare-lang && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "hare-lang" agent skill from https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang into .agents/skills/hare-lang/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hare-lang", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install mohitmishra786/low-level-dev-skills hare-lang --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/languages/hare-lang .cursor/skills/hare-lang && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "hare-lang" agent skill from https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang into .cursor/skills/hare-lang/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hare-lang", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/mohitmishra786/low-level-dev-skills.git --path skills/languages/hare-lang

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install mohitmishra786/low-level-dev-skills hare-lang --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/languages/hare-lang .gemini/skills/hare-lang && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "hare-lang" agent skill from https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang into .gemini/skills/hare-lang/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hare-lang", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install mohitmishra786/low-level-dev-skills hare-lang

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/languages/hare-lang .github/skills/hare-lang && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "hare-lang" agent skill from https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang into .github/skills/hare-lang/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hare-lang", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install mohitmishra786/low-level-dev-skills hare-lang --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/languages/hare-lang .opencode/skills/hare-lang && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "hare-lang" agent skill from https://github.com/mohitmishra786/low-level-dev-skills/tree/main/skills/languages/hare-lang into .opencode/skills/hare-lang/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hare-lang", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: hare-lang
GitHub stars: 253
Token cost: ~1.4k tokens
SKILL.md length: 333 words
Files: 1
Skills in repo: 138
Repo updated: Jun 27, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Hare language skill for simple systems programming. An agent skill from mohitmishra786/low-level-dev-skills.

Works in 9 steps: Install Hare → Hello world and build → Stdlib overview → …
Building with hare build/test/run
SKILL.md covers Purpose, When to Use, Workflow and Common Problems, plus 1 more section
Calls make and git; reaches git.sr.ht

What it does

Hare Lang is an agent skill from mohitmishra786/low-level-dev-skills. Hare language skill for simple systems programming. Use when building with hare build/test/run, Hare stdlib, C FFI with @extern, tagged union error handling, or comparing Hare vs C/Zig. Activates on queries about Hare language, hare build, @extern, tagged union, or Hare stdlib.

Its SKILL.md is about 1.4k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development, covering Error handling. The repository describes itself as: A curated suite of AI agent skills for systems and low-level programming with C/C++, Rust, and Zig toolchains, covering compilers, debuggers, profilers, build systems…. The licence is MIT.

When your agent uses it

Building with hare build/test/run
C FFI with @extern
Tagged union error handling
Comparing Hare vs C/Zig

Example prompts

“/hare-lang”

Workflow steps

9 steps, taken from the step headings in SKILL.md.

Install Hare
Hello world and build
Stdlib overview
Error handling
Type system
C FFI — @extern
Testing
Hare vs C vs Zig
Use cases

What it can do on your machine

Read from SKILL.md and the folder at commit bdc5847. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- make
- git
From the folder's file list and the shell code blocks in SKILL.md.
Network
Hosts in commands or code, which the agent is likely to contact:
- git.sr.ht
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Hare Lang loads about 1.4k tokens when it runs. Until then it costs about 72 tokens; SKILL.md has 333 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~72
When it runs · the whole SKILL.md, loaded when a task matches: ~1.4k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NoteRuns commands with sudoSKILL.md:30
```
sudo make install
```

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from mohitmishra786/low-level-dev-skills at commit bdc5847, republished under its MIT licence (© mohitmishra786). 333 words, ~1,416 tokens.

Download SKILL.mdSave it as .claude/skills/hare-lang/SKILL.md (or your agent's skills folder).

name: hare-lang
description: Hare language skill for simple systems programming. Use when building with hare build/test/run, Hare stdlib, C FFI with @extern, tagged union error handling, or comparing Hare vs C/Zig. Activates on queries about Hare language, hare build, @extern, tagged union, or Hare stdlib.

Hare

Purpose

Guide agents through the Hare programming language: design philosophy (simple, stable, compiled), hare build/test/run workflows, stdlib overview, C FFI with @extern, the type system (tagged unions, slices), error handling with (T | error!), and comparison with C and Zig for systems utilities.

When to Use

Writing small system utilities with C-like control and modern safety
Building CLI tools or daemons with minimal dependencies
Calling C libraries from Hare or exporting Hare functions to C
Preferring explicit error handling over exceptions
Evaluating Hare vs C or Zig for a new project
Needing a stable, auditable codebase without heavy runtime

Workflow

1. Install Hare

bash

# Linux/macOS — build from source
git clone https://git.sr.ht/~sircmpwn/hare
cd hare
make check   # builds and runs tests
sudo make install

hare version

bash

# Create project (Hare has no project generator — lay out manually)
mkdir -p mytool && cd mytool
cat > hare.mod << 'EOF'
module mytool
EOF

2. Hello world and build

hare

// main.ha
use fmt;

export fn main() void = {
	fmt::println("Hello, Hare!")!;
};

bash

hare build -o mytool
./mytool

hare run .        # build and run
hare test         # run tests

3. Stdlib overview

Module	Purpose
`fmt`	Formatted I/O (`printf`, `println`)
`io`	Reader/writer interfaces
`os`	Files, environment, args
`strings`	String manipulation
`bufio`	Buffered I/O
`encoding`	JSON, hex, etc.
`net`	TCP/UDP networking
`time`	Dates and durations
`mem`	Memory helpers
`types`	Platform integer types

hare

use os;
use fmt;
use strings;

export fn main() void = {
	const args = os::args;
	for (let i = 0z; i < len(args); i += 1) {
		fmt::println(args[i])!;
	};
};

4. Error handling

hare

// Errors are tagged union values — explicit propagation with !
fn read_file(path: str) (str | os::error) = {
	const file = os::open(path)?;
	defer os::close(file);
	let buf: []u8 = [];
	io::readall(file, &buf)?;
	return strings::fromutf8(buf)!;
};

export fn main() void = {
	match (read_file("config.txt")) {
	case let s: str =>
		fmt::println(s)!;
	case let err: os::error =>
		fmt::fatalf("error: {}", err)!;
	};
};

? propagates errors; ! asserts success in infallible context; match for handling.

5. Type system

hare

// Tagged union
type color = (u8 | u16 | void);

fn get_color(c: color) u16 = {
	match (c) {
	case let v: u8 => return v: u16;
	case let v: u16 => return v;
	case => abort();
	};
};

// Slices — pointer + length
fn sum(nums: []i32) i32 = {
	let total = 0i32;
	for (let i = 0z; i < len(nums); i += 1) {
		total += nums[i];
	};
	return total;
};

No implicit conversions — explicit casts required.

6. C FFI — @extern

hare

// Link against C library
use c;

@extern("c") fn strlen(s: *const u8) size;

export fn main() void = {
	const s = "hello";
	fmt::println(len(s))!;  // Hare strlen via strings module
};

Export Hare to C:

hare

// Exported C ABI function
export fn my_add(a: i32, b: i32) i32 = {
	return a + b;
};

bash

hare build -o libmytool.a
# Link from C with generated headers or manual declarations

hare

// cgo-style module linking in hare.mod
module mytool
require (
    libc
)

7. Testing

hare

@test fn test_add() void = {
	assert(sum(&[1i32, 2, 3]) == 6);
};

@test fn test_error() void = {
	match (read_file("/nonexistent")) {
	case => abort("expected error");
	case let err: os::error => void;
	};
};

bash

hare test -v

8. Hare vs C vs Zig

Aspect	Hare	C	Zig
Memory safety	Some (no null, tagged errors)	Manual	Manual + optional safety
Compile time	Fast	Fast	Comptime heavy
Stdlib	Minimal, stable	libc	Extensive
C interop	`@extern`	Native	`@cImport`
Generics	No (comptime limited)	No	Comptime generics
Best for	Utilities, tools	Everything	Systems with metaprogramming

9. Use cases

Good Hare fits
├── CLI utilities (grep-like, init tools)
├── Build tools and scripts replacing shell
├── Network daemons with simple protocol
└── Auditable security-sensitive code

Consider C/Zig instead when
├── Heavy generic metaprogramming needed (Zig)
├── Existing massive C ecosystem glue
└── GPU/kernel domains with immature Hare support

Common Problems

Symptom	Cause	Fix
`unknown type`	Missing import	Add `use module;`
FFI link error	Library not in hare.mod	Add require; correct `-l` flags
Error not handled	Missing `?` or match	Propagate or handle all cases
UTF-8 error	Invalid bytes in string	Validate with `strings::fromutf8`
Test not found	Missing `@test`	Name fn with `@test` attribute
Platform syscall missing	Hare stdlib gap	Use `@extern` to libc

skills/zig/zig-compiler — Zig as alternative systems language
skills/zig/zig-cinterop — Zig C interop comparison
skills/compilers/gcc — C toolchain alongside Hare
skills/languages/carbon-lang — other emerging systems languages
skills/build-systems/make — integrating Hare into Makefiles
skills/runtime-safety/sanitizers — C interop safety testing

Files

Just SKILL.md in skills/languages/hare-lang of mohitmishra786/low-level-dev-skills.

Open the folder on GitHubat commit bdc5847

Compare with similar skills

Hare Lang next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Hare Lang compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Hare Lang this skillmohitmishra786/low-level-dev-skills	253	—	~1.4k	Automated safety check: Notes	MIT	3 mo ago
Mole Bug Patternstw93/Mole	70k	—	~2k	Automated safety check: Pass	GPL-3.0	today
Native Data FetchingCherryHQ/cherry-studio-app	4k	6 repos	~2.9k	Automated safety check: Notes	MIT	today
Rust Best Practicesfarm-fe/farm	5.6k	3 repos	~1.1k	Automated safety check: Pass	MIT	17 days ago
R Function Input Validationtidyverse/dplyr	5.1k	1 repos	~2.3k	Automated safety check: Pass	Custom licence	4 mo ago
Next Best Practicesvercel-labs/openreview	1.7k	18 repos	~1k	Automated safety check: Pass	None	7 mo ago

Similar skills

Mole Bug Patterns
tw93/Mole
A catalog of recurring bug shapes in the Mole Mac cleaner, used to review safety-sensitive diffs for deletion safety, unbounded commands, shell traps and weak tests.
70k GitHub stars~2k tokensUpdated today
DevelopmentAuto-check passed
Native Data Fetching
CherryHQ/cherry-studio-app
A skill your agent uses when implementing or debugging ANY network request, API call, or data fetching.
4k GitHub starsUsed in 6 repos~2.9k tokens
DevelopmentAuto-check: notes
Rust Best Practices
farm-fe/farm
Guide for writing idiomatic Rust code based on Apollo GraphQL's best practices handbook.
5.6k GitHub starsUsed in 3 repos~1.1k tokens
DevelopmentAuto-check passed
R Function Input Validation
tidyverse/dplyr
Validates arguments of exported R functions with the standalone check_* type checkers from rlang, in tidyverse style with clear error messages.
5.1k GitHub starsUsed in 1 repo~2.3k tokens
DevelopmentAuto-check passed
Next Best Practices
vercel-labs/openreview
Official
Next.js best practices - file conventions, RSC boundaries, data patterns, async APIs, metadata, error handling, route handlers, image/font optimization, bundling
1.7k GitHub starsUsed in 18 repos~1k tokens
DevelopmentAuto-check passed
Error Handling
microsoft/data-formulator
Official
统一错误处理系统。在添加 API 端点、修改错误处理、添加前端 API 调用、编写错误相关测试时使用. An agent skill from microsoft/data-formulator.
18k GitHub stars~3.8k tokensUpdated yesterday
DevelopmentAuto-check passed

Questions about Hare Lang

What does Hare Lang do?

Hare language skill for simple systems programming. An agent skill from mohitmishra786/low-level-dev-skills. Hare Lang is an agent skill from mohitmishra786/low-level-dev-skills. Hare language skill for simple systems programming.

When should I use Hare Lang?

Hare Lang fits situations like: building with hare build/test/run; C FFI with @extern; tagged union error handling; comparing Hare vs C/Zig.

How do I install Hare Lang in Claude Code?

Run `npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a claude-code`. Or copy the skill folder (skills/languages/hare-lang in mohitmishra786/low-level-dev-skills) into .claude/skills/hare-lang in your project. Claude Code loads it when a task matches its description.

How do I install Hare Lang in Codex?

Run `npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a codex`. Or copy the skill folder (skills/languages/hare-lang in mohitmishra786/low-level-dev-skills) into .agents/skills/hare-lang in your project. Codex loads it when a task matches its description.

Can I use Hare Lang in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add mohitmishra786/low-level-dev-skills --skill hare-lang -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/hare-lang, .gemini/skills/hare-lang, .github/skills/hare-lang and .opencode/skills/hare-lang in your project.

What does Hare Lang need to run?

Going by SKILL.md and its folder, Hare Lang needs the command-line tools its instructions call (make and git).

Does Hare Lang access the network?

SKILL.md names 1 domain. In commands or code: git.sr.ht; the agent is likely to contact it when it follows the instructions. This is read from the text; nothing was executed.

Is Hare Lang safe to install?

Our automated static check of SKILL.md found notes only (runs commands with sudo), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.

What licence does Hare Lang use?

Hare Lang is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Hare Lang use?

About 1.4k tokens (SKILL.md is roughly 5.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Hare Lang?

Skills that share tags, products or a category with Hare Lang: Mole Bug Patterns (tw93/Mole, 70k stars), Native Data Fetching (CherryHQ/cherry-studio-app, 4k stars), Rust Best Practices (farm-fe/farm, 5.6k stars) and R Function Input Validation (tidyverse/dplyr, 5.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Hare Lang?

mohitmishra786 (a GitHub user) maintains it in mohitmishra786/low-level-dev-skills, which has 253 GitHub stars. The repository holds 138 skills in this directory. The repository was last updated on June 27, 2026.

Source: mohitmishra786/low-level-dev-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Hare Lang

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Hare

Purpose

When to Use

Workflow

1. Install Hare

2. Hello world and build

3. Stdlib overview

4. Error handling

5. Type system

6. C FFI — @extern

7. Testing

8. Hare vs C vs Zig

9. Use cases

Common Problems

Related Skills

Files

Compare with similar skills

Similar skills

More from mohitmishra786/low-level-dev-skills

Related

Questions about Hare Lang