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 VincentChuWaiChow/vanguard-frontier-agentic --skill indirect-tax-einvoicing-advisorgit clone --depth 1 https://github.com/VincentChuWaiChow/vanguard-frontier-agenticWrote 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/vincentchuwaichow/vanguard-frontier-agentic/indirect-tax-einvoicing-advisor)<a href="https://agentmods.dev/skills/vincentchuwaichow/vanguard-frontier-agentic/indirect-tax-einvoicing-advisor"><img src="https://agentmods.dev/badge/skills/vincentchuwaichow/vanguard-frontier-agentic/indirect-tax-einvoicing-advisor/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/vincentchuwaichow/vanguard-frontier-agentic/indirect-tax-einvoicing-advisor"><img src="https://agentmods.dev/badge/skills/vincentchuwaichow/vanguard-frontier-agentic/indirect-tax-einvoicing-advisor.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 | $0.00050 | $0.07299 |
| Opus 5 | $0.00025 | $0.03649 |
| Sonnet 5 | $0.00010 | $0.01460 |
| Haiku 4.5 | $0.00005 | $0.00730 |
Grade A, and why
indirect-tax-einvoicing-advisor 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.
How it starts
The opening of the file, as written. The whole thing — 482 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Indirect Tax & E-Invoicing Advisor — Reference Skill
Purpose
Provide the complete multi-jurisdiction framework for indirect tax (VAT/GST) compliance and mandatory electronic invoicing advisory — from mandate status and technical format requirements through VAT treatment analysis, cross-border supply rules, and common compliance gap patterns.
Part 1: EU VAT Framework and ViDA Reform
EU VAT Directive 2006/112/EC — Core Structure
The EU VAT Directive (Council Directive 2006/112/EC) is the foundational legal instrument governing VAT across all 27 EU member states.
Key structural elements:
- Taxable persons (Art. 9): Any person carrying out economic activity independently
- Taxable transactions (Art. 2): Supply of goods, supply of services, intra-community acquisition, import
- Place of supply — goods (Art. 31–39): Generally where goods located at time of supply; special rules for dispatched/transported goods
- Place of supply — services (Art. 43–59b): B2B general rule — where customer established (reverse charge); B2C general rule — where supplier established; special rules for land, events, transport, digital services
- VAT rates (Art. 96–106): Standard rate ≥ 15%; reduced rates ≥ 5% for listed categories; zero rates permitted in specific cases
- Invoice requirements (Art. 226): 15 mandatory fields including date, sequential number, supplier/customer VAT number, description, amount, VAT rate, VAT amount
- Reverse charge (Art. 194–199b): Recipient accounts for VAT instead of supplier; mandatory for cross-border B2B services and optional for domestic supplies in certain sectors
ViDA — VAT in the Digital Age (Adopted March 2025)
ViDA (Council Directive amending Directive 2006/112/EC) was adopted by the EU Council in March 2025 and introduces three pillars:
Pillar 1 — Digital Reporting Requirements (DRR) and e-Invoicing:
| Timeline | Requirement |
|---|---|
| 2024 (member state option) | Member states may introduce domestic mandatory e-invoicing without EU derogation |
| 2028 | Intra-EU B2B transactions: structured e-invoice mandatory (EN 16931 compliant) |
| 2030 | Mandatory real-time digital reporting of intra-EU B2B transaction data to EU central system |
| 2030 | Domestic B2B e-invoicing harmonization with DRR standard |
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 12d ago First seen · 482 lines · 50 tokens per session scan A 7e60515bed15
indirect-tax-einvoicing-advisor is a skill published in the GitHub repository VincentChuWaiChow/vanguard-frontier-agentic (22 stars, last pushed yesterday), licensed Apache-2.0. It adds 50 tokens to every session and 7,299 once invoked, about $0.0003 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 2026-08-30.
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