loonheffingen-en-werkkosten

loonheffingen-en-werkkosten is a skill for Claude Code from johnhout/knowledge-work-belastingzaken. It costs 75 tokens per session (318 once invoked), scanned A, original, MIT.

A workflow assistant for Dutch payroll taxes, called loonheffingen, and the WKR, a scheme that governs certain employee benefits and expenses. It checks payroll records and supporting evidence.

In plain words
What is it for?
Use it for payroll-period checks, wage-tax evidence reviews, social-contribution controls, WKR attention points, reconciliation, and follow-up lists.
Why use it?
It helps reveal missing evidence, unusual changes, and classification questions before a payroll tax process is finalized.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the belastingadviseur plugin — 8 skills, 8 commands, 5 MCP servers shipped together

Good fit Use it for payroll-period checks, wage-tax evidence reviews, social-contribution controls, WKR attention points, reconciliation, and follow-up lists.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten
Install

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.

Any agent
npx skills add johnhout/knowledge-work-belastingzaken --skill loonheffingen-en-werkkosten
Clone the repo
git clone --depth 1 https://github.com/johnhout/knowledge-work-belastingzaken

Made for: Claude Code.

Or install belastingadviseur, the plugin that ships this one along with the rest of its 8 skills, 8 commands, 5 MCP servers.

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 loonheffingen-en-werkkosten

README.md
[![agentmods](https://agentmods.dev/badge/skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten/github.svg)](https://agentmods.dev/skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten)
Your own site
<a href="https://agentmods.dev/skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten"><img src="https://agentmods.dev/badge/skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten/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 loonheffingen-en-werkkosten

Your own site · 80×15
<a href="https://agentmods.dev/skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten"><img src="https://agentmods.dev/badge/skills/johnhout/knowledge-work-belastingzaken/loonheffingen-en-werkkosten.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 318 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 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 $0.00075 $0.00318
Opus 5 $0.00037 $0.00159
Sonnet 5 $0.00015 $0.00064
Haiku 4.5 $0.00007 $0.00032

Measured 12d ago against content hash ed55b6d9865d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

loonheffingen-en-werkkosten 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 12d 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.

skills/loonheffingen-en-werkkosten/SKILL.md · 47 lines

What it actually says

Loonheffingen en Werkkosten

Use this skill to prepare payroll tax processes and WKR-oriented checks.

Scope

  • Payroll period control workflow
  • Loonheffing evidence checks
  • WKR attention point tracking

Boundaries

  • Do not provide final legal or payroll advice.
  • Do not conclude compliance without verified evidence.
  • Keep unresolved classification issues explicit.

Workflow

  1. Confirm employer entity and period scope.
  2. Reconcile payroll administration figures with source exports.
  3. Check for unusual deviations and categorization issues.
  4. Prepare filing-readiness and follow-up checklist.

Official Source Verification

  1. Verify payroll filing requirements and timing on belastingdienst.nl.
  2. Verify article-level references on wetten.overheid.nl where needed.
  3. Include URL and retrieval date.
  4. Mark claims as unverified if official references are unavailable.

Escalation Points

Escalate when:

  • Employee/tax classification is unclear
  • WKR treatment has high financial impact
  • Reconciliation gaps remain unresolved
  • Significant corrections are required

Safety

This skill supports payroll tax workflows and does not replace professional advice.

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. 12d ago First seen · 47 lines · 75 tokens per session scan A ed55b6d9865d

Subscribe to this mod's changes

loonheffingen-en-werkkosten is a skill published in the GitHub repository johnhout/knowledge-work-belastingzaken (6 stars, last pushed 7mo ago), licensed MIT. It adds 75 tokens to every session and 318 once invoked, about $0.0004 per session on Opus 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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