veryfront-code: Skill for Claude Code

.claude/skills/vf-testing/SKILL.md

vf-testing is a skill for Claude Code from veryfront/veryfront-code. It costs 36 tokens per session (958 once invoked), scanned A, original, Apache-2.0.

A testing guide for the Veryfront project using Deno's test runner and BDD-style tests. BDD means organising tests around observable behaviour, such as what a feature should do.

In plain words
What is it for?
Writing or debugging unit, integration, and end-to-end tests, choosing test locations, running the project's test commands, and following its test utilities and cleanup rules.
Why use it?
It helps tests remain isolated, properly cleaned up, and placed in the right location for their scope.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is veryfront/veryfront-code's own configuration. It tells Claude Code how to work on veryfront-code 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 veryfront-code configures →

Reuse

Borrowing it

Nothing to install: this file belongs to veryfront/veryfront-code. 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/veryfront/veryfront-code/main/.claude/skills/vf-testing/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/veryfront/veryfront-code

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 vf-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/veryfront/veryfront-code/vf-testing/github.svg)](https://agentmods.dev/skills/veryfront/veryfront-code/vf-testing)
Your own site
<a href="https://agentmods.dev/skills/veryfront/veryfront-code/vf-testing"><img src="https://agentmods.dev/badge/skills/veryfront/veryfront-code/vf-testing/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 vf-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/veryfront/veryfront-code/vf-testing"><img src="https://agentmods.dev/badge/skills/veryfront/veryfront-code/vf-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 958 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Tool Misuse · line 18
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
  • high Tool Misuse · line 21
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
  • medium MCP Rug Pull · line 123
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
Origin original 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 $0.00036 $0.00958
Opus 5.5 $0.00014 $0.00383
Sonnet 5.5 $0.00007 $0.00192
Haiku 4.5 $0.00004 $0.00096

Measured 2mo ago against content hash 0692a0157058, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

vf-testing 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 2mo 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/vf-testing/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Veryfront Testing Patterns

Overview

Veryfront uses Deno's test runner with BDD-style tests. Tests are either colocated unit tests or separate integration tests.

Core principle: Tests must be self-contained, use proper cleanup, and never share state.

Test Command

# Unit tests (colocated in src/)
VF_DISABLE_LRU_INTERVAL=1 SSR_TRANSFORM_PER_PROJECT_LIMIT=0 REVALIDATION_PER_PROJECT_LIMIT=0 NODE_ENV=production LOG_FORMAT=text deno test --no-check --allow-all --unstable-worker-options --unstable-net --parallel '--ignore=tests,src/ai/workflow/__tests__,src/cli/commands/*.integration.test.ts'

# All tests (unit + integration)
VF_DISABLE_LRU_INTERVAL=1 SSR_TRANSFORM_PER_PROJECT_LIMIT=0 REVALIDATION_PER_PROJECT_LIMIT=0 NODE_ENV=production LOG_FORMAT=text deno test --no-check --allow-all --unstable-worker-options --unstable-net

# Or use deno tasks
deno task test:unit
deno task test:integration
deno task test

File Placement

Type Location When
Unit test src/module/name.test.ts Pure functions, no I/O, no server
Integration test tests/integration/feature/name.test.ts Needs TestContext, server, filesystem
E2E test tests/e2e/ Full user flows (Playwright)
Index export test src/module/index.test.ts Verifies public API exports

Test Structure (BDD)

import { describe, it } from "#veryfront/testing/bdd";
import { assertEquals, assertThrows, assertRejects } from "#veryfront/testing/assert";

describe("ComponentName", () => {
  describe("methodName", () => {
    it("should return expected result when given valid input", () => {
      // Arrange
      const input = createInput();

      // Act
      const result = method(input);

      // Assert
      assertEquals(result, expected, "descriptive message");
    });
  });
});

Test Utilities

// Resource management (integration tests)
import { withTestContext } from "#veryfront/testing";

// TestContext provides:
// - context.allocatePort() — no hard-coded ports
// - context.createServer() — managed server lifecycle
// - Automatic cleanup on test end

// Filesystem isolation
import { withTempDir, withTempFile } from "#veryfront/testing";

// Environment isolation
import { withEnv } from "#veryfront/testing";

// Async helpers
import { delay, waitFor } from "#veryfront/testing";

// Cleanup registration
import { registerTestCleanup } from "#veryfront/testing";

Read the full file on GitHub · 130 lines

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. 2mo ago First seen · 130 lines · 36 tokens per session scan A 0692a0157058

Subscribe to this mod's changes

vf-testing is a skill published in the GitHub repository veryfront/veryfront-code (20 stars, last pushed yesterday), licensed Apache-2.0. It adds 36 tokens to every session and 958 once invoked, about $0.0001 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 2026-08-30.

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