Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add berkcangumusisik/claude-code-practices --skill error-handlergit clone --depth 1 https://github.com/berkcangumusisik/claude-code-practicesWrote 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/berkcangumusisik/claude-code-practices/error-handler)<a href="https://agentmods.dev/skills/berkcangumusisik/claude-code-practices/error-handler"><img src="https://agentmods.dev/badge/skills/berkcangumusisik/claude-code-practices/error-handler/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/berkcangumusisik/claude-code-practices/error-handler"><img src="https://agentmods.dev/badge/skills/berkcangumusisik/claude-code-practices/error-handler.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00016 | $0.00316 |
| Opus 5.5 | $0.00006 | $0.00126 |
| Sonnet 5.5 | $0.00003 | $0.00063 |
| Haiku 4.5 | $0.00002 | $0.00032 |
Grade A, and why
error-handler scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Generate Error Handling System
- Check existing error handling:
grep -rn "catch\|try\|throw\|Error(" src/ --include="*.ts" -l | head -10
grep -rn "class.*Error" src/ --include="*.ts" | head -10
- Generate typed error classes:
export class AppError extends Error {
constructor(
message: string,
public readonly statusCode: number,
public readonly code: string,
public readonly isOperational = true,
) {
super(message)
this.name = this.constructor.name
}
}
export class NotFoundError extends AppError {
constructor(resource: string) {
super(`${resource} not found`, 404, 'NOT_FOUND')
}
}
export class ValidationError extends AppError {
constructor(details: ZodIssue[]) {
super('Validation failed', 400, 'VALIDATION_ERROR')
}
}
export class UnauthorizedError extends AppError {
constructor() { super('Unauthorized', 401, 'UNAUTHORIZED') }
}
-
Generate global error handler middleware.
-
Add
Result<T, E>type for functions that can fail without throwing. -
Replace generic
try/catchblocks with typed errors throughout the codebase.
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.
- 1mo ago First seen · 53 lines · 16 tokens per session scan A d22959de1f88
error-handler is a skill published in the GitHub repository berkcangumusisik/claude-code-practices (11 stars, last pushed 6mo ago), licensed MIT. It adds 16 tokens to every session and 316 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 2026-08-31.
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