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.
curl -O https://raw.githubusercontent.com/veryfront/veryfront-code/main/.claude/skills/vf-error-handling/SKILL.mdgit clone --depth 1 https://github.com/veryfront/veryfront-codeWrote 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.
[](https://agentmods.dev/skills/veryfront/veryfront-code/vf-error-handling)<a href="https://agentmods.dev/skills/veryfront/veryfront-code/vf-error-handling"><img src="https://agentmods.dev/badge/skills/veryfront/veryfront-code/vf-error-handling/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.
<a href="https://agentmods.dev/skills/veryfront/veryfront-code/vf-error-handling"><img src="https://agentmods.dev/badge/skills/veryfront/veryfront-code/vf-error-handling.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00030 | $0.01058 |
| Opus 5.5 | $0.00012 | $0.00423 |
| Sonnet 5.5 | $0.00006 | $0.00212 |
| Haiku 4.5 | $0.00003 | $0.00106 |
Grade A, and why
vf-error-handling 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.
How it starts
The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Veryfront Error Handling
Overview
Veryfront uses a centralized error registry with slug-based identification. All errors extend VeryfrontError and are created via defineError().
Core principle: Never throw raw Error. Use the registry. Never identify errors by class name. Use slugs.
Error Registry Pattern
Defining New Errors
// In src/errors/error-registry.ts
import { defineError } from "./types.ts";
export const MY_NEW_ERROR = defineError({
slug: "my-new-error", // kebab-case, unique
category: "RUNTIME", // CONFIG | BUILD | RUNTIME | ROUTE | MODULE | SERVER | BOUNDARY | DEV | DEPLOY | AGENT | GENERAL
status: 500, // default HTTP status
title: "Something went wrong", // human-readable
suggestion: "Try doing X instead", // actionable fix
});
Throwing Errors
import { MY_NEW_ERROR } from "#veryfront/errors";
throw MY_NEW_ERROR.create({
detail: "Specific description of what happened",
context: { key: "value", relevantData: data },
cause: originalError, // optional: chain the original error
});
Catching Errors
import { VeryfrontError } from "#veryfront/errors";
try {
riskyOperation();
} catch (error) {
if (error instanceof VeryfrontError && error.slug === "my-new-error") {
// Handle specific error
console.log(error.context.relevantData);
}
throw error; // Re-throw unknown errors
}
Migrating Class-Based Errors to Registry
When replacing class FooError extends Error:
Step 1: Define in Registry
// src/errors/error-registry.ts
export const FOO_ERROR = defineError({
slug: "foo-error",
category: "RUNTIME",
status: 500,
title: "Foo operation failed",
suggestion: "Check the foo configuration",
});
Step 2: Update Usage Sites
// Before
throw new FooError("something failed", { details: data });
// After
throw FOO_ERROR.create({
detail: "something failed",
context: { details: data },
});
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.
- 2mo ago First seen · 153 lines · 30 tokens per session scan A 8ef54cba13ad
vf-error-handling is a skill published in the GitHub repository veryfront/veryfront-code (20 stars, last pushed yesterday), licensed Apache-2.0. It adds 30 tokens to every session and 1,058 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.
vf-error-handling compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| vf-error-handlingveryfront/veryfront-code | Skill | 20 | yesterday | Apache-2.0 | A | 30 | Claude Code |
| investigateAbyssCN/oh-my-dag | Skill | 44 | 26d ago | MIT | A | 77 | Claude Code, Codex |
| bugfix-triageAbyssCN/oh-my-dag | Skill | 44 | 26d ago | MIT | A | 37 | Claude Code, Codex |
| typescript-testingComposioHQ/composio | Skill | 31k | yesterday | MIT | A | 92 | Claude Code, Codex |
| cli-e2eComposioHQ/composio | Skill | 31k | yesterday | MIT | A | 62 | Claude Code, Codex |
| ios-simulatorcallstack/agent-device | Skill | 5.3k | yesterday | MIT | A | 69 | Claude Code, Codex |
| cvm-ai-doctorTencentCloud/Octop | Skill | 12k | yesterday | MIT | A | 70 | Claude Code, Codex |