Tax Engine is answering right now. Last checked 7 min ago. It exposes 14 tools.
Deterministic Czech OSVC tax tools for 2026: tax, insurance, deadlines, VAT and exchange rates.
Uptime history
91 days of history · worst day 0%
91 days agonow
100.0%
Uptime 24h
91 of 91 checks
14
Tools
read from the server
245 ms
Response time
average over 24h
open, no key
Access
streamable-http
Nothing serious here today
Today is the operative word: we check Tax Engine every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
Connect this server
Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 7 min ago.
run in your terminal
claude mcp add tax-engine --transport http https://freelax.cz/api/mcpSettings → Connectors → Add custom connector, then paste this address
https://freelax.cz/api/mcp~/.codex/config.toml
[mcp_servers.tax-engine]
url = "https://freelax.cz/api/mcp".cursor/mcp.json
{
"mcpServers": {
"tax-engine": {
"url": "https://freelax.cz/api/mcp"
}
}
}.vscode/mcp.json
{
"servers": {
"tax-engine": {
"type": "http",
"url": "https://freelax.cz/api/mcp"
}
}
}Available tools 14
Read directly from the server with tools/list, grouped by what they act on.
If a tool disappears, we record the date.
calc
calc_flat_tax_settlement
Given the paušální daň band you paid and the actual annual income, computes whether you owe a doplatek (top-up), get a vratka (refund), or must exit the flat-tax regime (income above 2,000,000 CZK).
calc_set_aside
How much of a monthly OSVČ income to set aside for Czech income tax, social and health insurance, and what remains safe to spend. Supports mixed §7 business + §9 rental income and the paušální daň (flat tax) regimes.
flat
check_flat_tax_eligibility
Screens whether an OSVČ may enter or stay in the paušální daň (flat tax) regime: public health insurance participation (decisive for foreigners), VAT-payer status, income ceiling 2,000,000 CZK, side income and secondary activity. Returns reasons with severity.
get_flat_tax_band
Which paušální daň band (pásmo 1/2/3) an annual income falls into given the expense flat-rate, the current monthly payment for that band, and the next income threshold to watch.
compare
compare_regimes
Compares the standard OSVČ regime against paušální daň (flat tax) for a yearly income, including tax credits that would be lost with the flat tax (children, spouse), and recommends the cheaper regime.
compute
compute_year
Computes a full Czech OSVČ tax year from personal facts: income tax with credits (children, spouse, deductions), social and health insurance, monthly set-aside, safe-to-spend, flat-tax band and regime-eligibility evaluation. All figures come from the deterministic Freelax engine, never from the model.
convert
convert_eur_czk
Converts an EUR amount to CZK using the Czech National Bank daily exchange rate (the rate used for Czech tax purposes). Reports the rate, its publication date and whether a stale cached ČNB publication had to be used. Fails closed when no verified ČNB rate is available.
czech
czech_working_days
Czech public holidays for a year (including movable Easter feasts) and, for a specific date, whether it is a working day and the next working day a statutory deadline would shift to.
estimate
estimate_penalty
Estimates the Czech penalty/interest for a late payment or filing: repo rate + 8 p.p. for insurance and tax interest (3.5% H1 / 3.75% H2 2026), 3 grace days for tax payments, 200 CZK health aggregation floor and the 1,000 CZK tax non-assessment threshold. A dated estimate is rejected when its required rate period falls outside the implemented history.
filing
get_filing_deadlines
Deadline for the Czech personal income tax return (DPFO) for a given tax year, per filing route: paper, self-filed electronic, or via tax advisor. Weekend and holiday shifts are applied.
prehled
get_prehled_deadlines
Filing deadlines for the annual OSVČ Přehled o příjmech a výdajích for both social insurance (ČSSZ) and the health insurer, per tax-return filing route, plus the payment due date (8 calendar days after the filing deadline).
rule
get_rule_source
For a Czech OSVČ tax topic, returns the governing rule with current values, primary-source citations (zákon, ČSSZ, VZP, Finanční správa) with verification dates, and related Freelax articles. Topics: pausalni_dan, identifikovana_osoba, dph_registrace, zalohy, prehledy, penale, danove_pasmo_23, vedlejsi_cinnost.
thresholds
check_thresholds
Checks an annual income against the four statutory thresholds: VAT registration 2,000,000 CZK, immediate VAT registration 2,536,500 CZK, the 23% higher tax bracket, and the paušální daň eligibility ceiling. Reports approaching (90%), exceeded and remaining amounts.
trigger
check_io_trigger
Checks whether buying services from abroad (Google Ads, Meta, ChatGPT, hosting…) or selling services to EU businesses has made an OSVČ an identifikovaná osoba under § 6h/§ 6i ZDPH, with the 15-day registration deadline (§ 97) and fact-freshness handling. Verdict: ok / check / act_now.
Endpoints
| URL | Transport | State | Latency | Checked |
|---|---|---|---|---|
| https://freelax.cz/api/mcp | streamable-http | answering | 238 ms | 7 min ago |
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Tax Engine — questions
Answers built from our own checks of this server.
What can Tax Engine do?
It exposes 14 tools, read directly from the server on our last check. Among them: calc_flat_tax_settlement, calc_set_aside, check_flat_tax_eligibility, check_io_trigger, check_thresholds, compare_regimes and 8 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README.
How MCP servers expose tools in the first place →
What is Tax Engine mostly used for?
Its tools cluster around calc and flat. That is what this server is built to work with — the grouping comes from the actual tool names, not from a category we assigned.
Is Tax Engine working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 91 of 91 checks got a reply (100.0%), average response time 245 ms. The bar chart above shows every period we have measured.
How do I connect Tax Engine?
Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does Tax Engine need an API key?
No. Tax Engine completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 14 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is Tax Engine?
It answers our handshake in 245 ms on average, which is faster than 56% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.