Agent skill

Felt Construction

A skill your agent uses when constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved.

MITAuto-check passedDevelopment

Install Felt Construction

skills CLI

$ npx skills add 0xMiden/protocol --skill felt-construction -a claude-code

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

GitHub CLI

$ gh skill install 0xMiden/protocol felt-construction --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/0xMiden/protocol.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/felt-construction .claude/skills/felt-construction && 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 "felt-construction" agent skill from https://github.com/0xMiden/protocol/tree/next/.claude/skills/felt-construction into .claude/skills/felt-construction/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "felt-construction", 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/0xMiden/protocol/tree/next/.claude/skills/felt-construction

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 0xMiden/protocol --skill felt-construction -a codex

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

GitHub CLI

$ gh skill install 0xMiden/protocol felt-construction --agent codex

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

Manual copy

$ git clone --depth 1 https://github.com/0xMiden/protocol.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/felt-construction .agents/skills/felt-construction && 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 "felt-construction" agent skill from https://github.com/0xMiden/protocol/tree/next/.claude/skills/felt-construction into .agents/skills/felt-construction/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "felt-construction", 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 0xMiden/protocol --skill felt-construction -a cursor

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

GitHub CLI

$ gh skill install 0xMiden/protocol felt-construction --agent cursor

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

Manual copy

$ git clone --depth 1 https://github.com/0xMiden/protocol.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/felt-construction .cursor/skills/felt-construction && 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 "felt-construction" agent skill from https://github.com/0xMiden/protocol/tree/next/.claude/skills/felt-construction into .cursor/skills/felt-construction/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "felt-construction", 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/0xMiden/protocol.git --path .claude/skills/felt-construction

--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 0xMiden/protocol --skill felt-construction -a gemini-cli

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

GitHub CLI

$ gh skill install 0xMiden/protocol felt-construction --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/0xMiden/protocol.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/felt-construction .gemini/skills/felt-construction && 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 "felt-construction" agent skill from https://github.com/0xMiden/protocol/tree/next/.claude/skills/felt-construction into .gemini/skills/felt-construction/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "felt-construction", 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 0xMiden/protocol felt-construction

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 0xMiden/protocol --skill felt-construction -a github-copilot

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

Manual copy

$ git clone --depth 1 https://github.com/0xMiden/protocol.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/felt-construction .github/skills/felt-construction && 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 "felt-construction" agent skill from https://github.com/0xMiden/protocol/tree/next/.claude/skills/felt-construction into .github/skills/felt-construction/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "felt-construction", 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 0xMiden/protocol --skill felt-construction -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 0xMiden/protocol felt-construction --agent opencode

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

Manual copy

$ git clone --depth 1 https://github.com/0xMiden/protocol.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/felt-construction .opencode/skills/felt-construction && 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 "felt-construction" agent skill from https://github.com/0xMiden/protocol/tree/next/.claude/skills/felt-construction into .opencode/skills/felt-construction/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "felt-construction", 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: felt-construction
GitHub stars: 133
Token cost: ~439 tokens
SKILL.md length: 114 words
Files: 1
Skills in repo: 35
Repo updated: Oct 8, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

A skill your agent uses when constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved.

Constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved
SKILL.md covers Rule, Why and Examples
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Felt Construction is an agent skill from 0xMiden/protocol. Use when constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved.

Its SKILL.md is about 440 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. It works with Rust. The repository describes itself as: Core components of the Miden protocol. The licence is MIT.

When your agent uses it

Constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved

Example prompts

“/felt-construction”

What it can do on your machine

Read from SKILL.md and the folder at commit 5f6a246. 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
No scripts in the folder and no shell commands in SKILL.md (its code samples are rust).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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

Felt Construction loads about 439 tokens when it runs. Until then it costs about 38 tokens; SKILL.md has 114 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~38
When it runs · the whole SKILL.md, loaded when a task matches: ~439

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 passed

The automated check found no risky patterns in SKILL.md.

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 0xMiden/protocol at commit 5f6a246, republished under its MIT licence (© 0xMiden). 114 words, ~439 tokens.

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

name: felt-construction
description: Use when constructing a `Felt` from a numeric value in Rust — use checked construction unless the canonical bound is already proved.

Felt Construction From Untrusted Numeric Inputs

Rule

Felt::new(x) is checked and returns Result, rejecting values greater than or equal to Felt::ORDER. Use it when a u64 input may exceed the field modulus.

Use one of:

Felt::from_u8(x), Felt::from_u16(x) or Felt::from_u32(x) for u32-or-smaller inputs. They are infallible and const, so prefer them to define constants.
Felt::from(x) for u32-or-smaller inputs in non-const code (infallible).
Felt::new(x) or Felt::try_from(x) for u64 inputs; both return Result and check the bound.
Felt::new_unchecked(x) only when x < Felt::ORDER has already been proved.

Why

The field modulus sits just below 2^64, so out-of-range inputs occupy a narrow band that tests can miss. Checked construction makes those inputs explicit errors; new_unchecked skips that protection.

Examples

rust

// Good: const constructor for a small constant
const NUM_SLOTS: Felt = Felt::from_u8(4);

// Good: u32 input, infallible conversion
let f = Felt::from(slot_index as u32);

// Good: untrusted u64 input, checked conversion returning Result
let f = Felt::new(user_value).map_err(|_| Error::FeltOverflow)?;

// Good: unchecked construction only after proving the canonical bound
assert!(bounded_value < Felt::ORDER);
let f = Felt::new_unchecked(bounded_value);

// Bad: unchecked construction on an untrusted value
let f = Felt::new_unchecked(user_value);

// Bad: new_unchecked for a constant that a const from_u* constructor covers
const NUM_SLOTS: Felt = Felt::new_unchecked(4);

Files

Just SKILL.md in .claude/skills/felt-construction of 0xMiden/protocol.

Open the folder on GitHubat commit 5f6a246

Compare with similar skills

Felt Construction 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.

Felt Construction compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Felt Construction this skill0xMiden/protocol	133	—	~439	Automated safety check: Pass	MIT	yesterday
Migrate Core Code to Submodulestinyhumansai/openhuman	42k	—	~2.6k	Automated safety check: Pass	GPL-3.0	today
OpenLogi macOS Permissions TriageAprilNEA/OpenLogi	23k	—	~2.5k	Automated safety check: Notes	Apache-2.0	today
Rust Best Practicesfarm-fe/farm	5.6k	3 repos	~1.1k	Automated safety check: Pass	MIT	17 days ago
RTK Rust Design Patternsrtk-ai/rtk	83k	—	~1.9k	Automated safety check: Pass	Apache-2.0	yesterday
Release Skillsnexmoe/eve	421	3 repos	~3.3k	Automated safety check: Pass	None	6 mo ago

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Works with

Rust

Questions about Felt Construction

What does Felt Construction do?

A skill your agent uses when constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved. Felt Construction is an agent skill from 0xMiden/protocol. Use when constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved.

When should I use Felt Construction?

Felt Construction fits situations like: constructing a Felt from a numeric value in Rust — use checked construction unless the canonical bound is already proved.

How do I install Felt Construction in Claude Code?

Run `npx skills add 0xMiden/protocol --skill felt-construction -a claude-code`. Or copy the skill folder (.claude/skills/felt-construction in 0xMiden/protocol) into .claude/skills/felt-construction in your project. Claude Code loads it when a task matches its description.

How do I install Felt Construction in Codex?

Run `npx skills add 0xMiden/protocol --skill felt-construction -a codex`. Or copy the skill folder (.claude/skills/felt-construction in 0xMiden/protocol) into .agents/skills/felt-construction in your project. Codex loads it when a task matches its description.

Can I use Felt Construction 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 0xMiden/protocol --skill felt-construction -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/felt-construction, .gemini/skills/felt-construction, .github/skills/felt-construction and .opencode/skills/felt-construction in your project.

What does Felt Construction need to run?

SKILL.md names no scripts, command-line tools or credentials: Felt Construction is instructions for the agent only.

Does Felt Construction access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Felt Construction safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Felt Construction use?

Felt Construction 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 Felt Construction use?

About 439 tokens (SKILL.md is roughly 1.8k 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 Felt Construction?

Skills that share tags, products or a category with Felt Construction: Migrate Core Code to Submodules (tinyhumansai/openhuman, 42k stars), OpenLogi macOS Permissions Triage (AprilNEA/OpenLogi, 23k stars), Rust Best Practices (farm-fe/farm, 5.6k stars) and RTK Rust Design Patterns (rtk-ai/rtk, 83k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Felt Construction?

0xMiden (a GitHub organization) maintains it in 0xMiden/protocol, which has 133 GitHub stars. The repository holds 35 skills in this directory. The repository was last updated on October 8, 2026.

Source: 0xMiden/protocol on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Felt Construction

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Felt Construction From Untrusted Numeric Inputs

Rule

Why

Examples

Files

Compare with similar skills

Similar skills

More from 0xMiden/protocol

Related

Questions about Felt Construction