Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/johnhout/knowledge-work-belastingzakennpx agentmods add commands/johnhout/knowledge-work-belastingzaken/btw-aangifteWrote 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/commands/johnhout/knowledge-work-belastingzaken/btw-aangifte)<a href="https://agentmods.dev/commands/johnhout/knowledge-work-belastingzaken/btw-aangifte"><img src="https://agentmods.dev/badge/commands/johnhout/knowledge-work-belastingzaken/btw-aangifte/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/commands/johnhout/knowledge-work-belastingzaken/btw-aangifte"><img src="https://agentmods.dev/badge/commands/johnhout/knowledge-work-belastingzaken/btw-aangifte.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 | $0.00007 | $0.00409 |
| Opus 5 | $0.00003 | $0.00204 |
| Sonnet 5 | $0.00001 | $0.00082 |
| Haiku 4.5 | $0.00001 | $0.00041 |
Grade A, and why
btw-aangifte 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 10d 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
BTW Aangifte / VAT Filing
If placeholders are unclear, see CONNECTORS.md.
Important / Belangrijk: This workflow support is not legal or fiscal advice. Require review by a qualified Dutch tax professional.
Prepare VAT filing workflow for monthly, quarterly, or annual reporting periods.
Usage
/belastingadviseur:btw-aangifte <tijdvak> [ondernemingsvorm]
Workflow
- Confirm reporting scope:
- Period and filing frequency
- Entity type and VAT registration context
- Gather VAT evidence:
- Sales and purchase data
- Intra-EU/extra-EU relevant transactions
- Corrections and prior period adjustments
- Build filing draft controls:
- Output VAT vs input VAT mapping
- Exception checks (missing invoices, reverse-charge patterns, unusual balances)
- Reconciliation against bookkeeping totals
- Official-source verification:
- Verify period deadlines, reporting rules, and procedural requirements on
belastingdienst.nl - Verify legal references as needed on
wetten.overheid.nl - Record URL and retrieval date per date/rule-sensitive item
- Fallback behavior:
- If
~~boekhoudingis unavailable, request manual exports and invoice summaries - If mandatory figures are missing, do not provide filing-ready conclusions
- If official verification fails, label relevant items as unverified
Required Output Format (Use Exactly)
Context / ContextAssumptions / AannamesRequired Documents / Benodigde stukkenStep-by-step / StappenplanChecks & Risks / Controles en risico'sNext Actions / Volgende actiesSources (official) / Bronnen (officieel)Professional Review Disclaimer / Disclaimer deskundige beoordeling
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.
- 10d ago First seen · 56 lines · 7 tokens per session scan A dd3276b33fb3
btw-aangifte is a command published in the GitHub repository johnhout/knowledge-work-belastingzaken (6 stars, last pushed 6mo ago), licensed MIT. It adds 7 tokens to every session and 409 once invoked, about $0.0000 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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tax-planning
Optimize tax liability or ensure tax compliance.
child-support-calc
A calculator for Japanese child support and marital living costs, using the revised standard calculation method published in 2019. Child support is money paid for a child after divorce; marital living costs are shared living expenses while spouses live apart.