b4: Skill for Claude Code

.claude/skills/b4-ui/SKILL.md

b4-ui is a skill for Claude Code from DanielLavrushin/b4. It costs 128 tokens per session (1,707 once invoked), scanned A, original, GPL-3.0.

A guide for changing b4's web interfaces, including the router UI, moderation console, and shared design package. It covers React-based screens, shared components, local development, and the two supported languages.

In plain words
What is it for?
Use it to modify b4 web pages, moderation screens, shared UI components, or the interface development loop.
Why use it?
It helps keep related interfaces and shared components consistent while accounting for the development setup and translated text.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is DanielLavrushin/b4's own configuration. It tells Claude Code how to work on b4 itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything b4 configures →

About the project

B4 is a Linux network packet-processing service that changes network traffic so deep packet inspection systems cannot identify or block its connections. It is used on routers, servers, and desktops to bypass DPI-based blocking, and a router installation can cover devices across the local network. The catalogue lists 12 skills associated with B4.

DanielLavrushin/b4 · 1,848 stars · on GitHub · docs.b4core.app

Reuse

Borrowing it

Nothing to install: this file belongs to DanielLavrushin/b4. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/DanielLavrushin/b4/main/.claude/skills/b4-ui/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/DanielLavrushin/b4

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for b4-ui

README.md
[![agentmods](https://agentmods.dev/badge/skills/daniellavrushin/b4/b4-ui/github.svg)](https://agentmods.dev/skills/daniellavrushin/b4/b4-ui)
Your own site
<a href="https://agentmods.dev/skills/daniellavrushin/b4/b4-ui"><img src="https://agentmods.dev/badge/skills/daniellavrushin/b4/b4-ui/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for b4-ui

Your own site · 80×15
<a href="https://agentmods.dev/skills/daniellavrushin/b4/b4-ui"><img src="https://agentmods.dev/badge/skills/daniellavrushin/b4/b4-ui.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,707 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00128 $0.01707
Opus 5.5 $0.00051 $0.00683
Sonnet 5.5 $0.00026 $0.00341
Haiku 4.5 $0.00013 $0.00171

Measured 6d ago against content hash 4995f7a446fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

b4-ui scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/b4-ui/SKILL.md · 96 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 96 lines · 128 tokens per session scan A 4995f7a446fa

Subscribe to this mod's changes

b4-ui is a skill published in the GitHub repository DanielLavrushin/b4 (1,848 stars, last pushed 4d ago), licensed GPL-3.0. It adds 128 tokens to every session and 1,707 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-31.

Related

b4-ui compared with skills from other repositories

b4-ui next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
b4-uiDanielLavrushin/b4Skill1.8k4d agoGPL-3.0A128Claude Code
build-ghost-appTryGhost/GhostSkill56ktodayMITA44Claude Code, Codex
chakra-ui-builderchakra-ui/chakra-uiSkill41kyesterdayMITA214Claude Code, Codex
material-ui-tailwindmui/material-uiSkill99kyesterdayMITA67Claude Code, Codex
fuzzy-rankingTanStack/tableSkill29k4d agoMITA62Claude Code, Codex
r3f-best-practiceszebbern/claude-code-guideSkill4.7k3d agoMITA74Claude Code, Codex
git-safetytamagui/tamaguiSkill14ktodayMITA0Claude Code