cz.freelax/tax-engine
REMOTE · FREELAX.CZ · SCANNED SEP 24
Deterministic Czech OSVC tax tools for 2026: tax, insurance, deadlines, VAT and exchange rates.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security66
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 14 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC is configured correctly; the domain's records validate against the full chain to the root. View diagnostics → Pass
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability65
- AI-judged instruction clarity (good).Pass
- Context-footprint check failed: tool/resource definitions use about 2291 tokens (~163/item across 14 items; 14 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage82
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 45% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 14 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 14 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
How do I install the cz.freelax/tax-engine MCP server?
cz.freelax/tax-engine is a hosted endpoint at https://freelax.cz/api/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · freelax.cz
claude mcp add --transport http cz-freelax-tax-engine 'https://freelax.cz/api/mcp'
{
"mcpServers": {
"cz-freelax-tax-engine": {
"url": "https://freelax.cz/api/mcp"
}
}
} {
"servers": {
"cz-freelax-tax-engine": {
"type": "http",
"url": "https://freelax.cz/api/mcp"
}
}
} [mcp_servers.cz-freelax-tax-engine] url = "https://freelax.cz/api/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"cz-freelax-tax-engine": {
"type": "remote",
"url": "https://freelax.cz/api/mcp",
"enabled": true
}
}
} openclaw mcp add cz-freelax-tax-engine --url 'https://freelax.cz/api/mcp' --transport streamable-http
mcp_servers:
cz-freelax-tax-engine:
url: "https://freelax.cz/api/mcp" {
"McpServers": {
"cz-freelax-tax-engine": {
"Transport": "http",
"Url": "https://freelax.cz/api/mcp"
}
}
} assistant mcp add cz-freelax-tax-engine -t streamable-http -u 'https://freelax.cz/api/mcp'
{
"mcpServers": {
"cz-freelax-tax-engine": {
"type": "http",
"url": "https://freelax.cz/api/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 31 Aug 26 +1
- Stability: 0.97 → pass security
- 29 Aug 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.
- 27 Aug 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 83 to 87. That category is still filling its 30-day observation window: 25 days of observed history at the previous scan, 26 at this one. The score rises as the window fills, whether or not the server changes.
- 26 Aug 26 76
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 11 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 2 Aug 26 0
- Schema quality: unverified → fair ▲ functional
- Stability: unverified → 0.03 ▲ functional
- 1 Aug 26 0
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 24 Sept 2026 · Probed https://freelax.cz/api/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=freelax.cz | CN=YR2,O=Let's Encrypt,C=US | 13 Aug 2026 | 11 Nov 2026 | RSA 2048 | SHA256-RSA | 56f79f95cd81fa6d3e89426a5710205025b |
| SANs: freelax.cz, www.freelax.cz | ||||||
| CN=YR2,O=Let's Encrypt,C=US (CA) | CN=Root YR,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | RSA 2048 | SHA256-RSA | 4ebd24947e24d394802d84a52fd5b319 |
| CN=Root YR,O=ISRG,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | RSA 4096 | SHA256-RSA | f24b6d17f9d9ad7cb1c9fea78782699f |
Background: What to check on a remote MCP endpoint →
DNSSEC secure
Validation of freelax.cz. — Secure
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| cz. | present | 20237 | 13 | Verified |
| freelax.cz. | present | 33701 | 13 | Verified |
| freelax.cz. | Verified address RRset verified with the apex keys |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=31536000; includeSubDomains; preload |
| content-security-policy | default-src 'self'; script-src 'self' 'unsafe-inline' https://js.stripe.com https://plausible.io; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:; connect-src 'self' https://api.stripe.com https://js.stripe.com https://*.sentry.io https://*.ingest.sentry.io https://plausible.io; frame-src 'self' https://js.stripe.com https://hooks.stripe.com; frame-ancestors 'none'; base-uri 'self'; form-action 'self' https://checkout.stripe.com https://appleid.apple.com; worker-src 'self' blob:; object-src 'none' |
| x-content-type-options | nosniff |
| x-frame-options | DENY |
| referrer-policy | strict-origin-when-cross-origin |
| permissions-policy | camera=(), microphone=(), geolocation=(), interest-cohort=(), accelerometer=(), gyroscope=(), magnetometer=(), payment=(), usb=() |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://freelax.cz/api/mcp | Verified | 200 | |
| http (plaintext) | http://freelax.cz/api/mcp | HTTPS enforced | 301 | https://freelax.cz/api/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
calc_flat_tax_settlement Paušální daň year-end settlement ~160
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).
| Name | Type | Req | Description |
|---|---|---|---|
| actualAnnualIncome | number | yes | – |
| currentBand | string | yes | Band actually paid during the year |
| flatRatePercent | – | – | Flat-rate expense percentage as a decimal: 0.4 (other business), 0.6 (most freelancers / živnost volná), 0.8 (craft trades) |
| isProjection | boolean | – | True for a mid-year projection instead of a final settlement |
| monthsInRegime | integer | – | – |
No output schema declared.
No examples provided.
calc_set_aside Monthly tax set-aside calculator ~219
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.
| Name | Type | Req | Description |
|---|---|---|---|
| activityType | string | – | – |
| advanceExempt | boolean | – | – |
| employerCoversHealth | boolean | – | – |
| flatRatePercent | – | – | Flat-rate expense percentage as a decimal: 0.4 (other business), 0.6 (most freelancers / živnost volná), 0.8 (craft trades) |
| monthlyIncome | number | yes | Gross monthly business income in CZK (§ 7 ZDP) |
| reducedMinimumBase | boolean | – | New OSVČ in the first 2 years (lower social minimum) |
| rentalMonthlyIncome | number | – | Monthly rental income in CZK (§ 9 ZDP); triggers the mixed-income calculation |
| secondaryThresholdExceeded | boolean | – | – |
| taxRegime | string | – | – |
No output schema declared.
No examples provided.
check_flat_tax_eligibility Paušální daň eligibility check ~197
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.
| Name | Type | Req | Description |
|---|---|---|---|
| activityType | string | – | – |
| annualIncome | number | yes | Expected annual business income in CZK |
| citizenshipType | string | – | eu = EU/EEA citizen; non_eu_public = non-EU participating in Czech public health insurance (e.g. dočasná ochrana, employment); non_eu_private = non-EU with private/commercial insurance only |
| isVATRegistered | boolean | – | Full VAT payer (plátce DPH). Identifikovaná osoba is NOT blocking. |
| publicHealthStatus | string | – | – |
| rentalAnnualIncome | number | – | – |
No output schema declared.
No examples provided.
check_io_trigger Identified person (identifikovaná osoba) trigger check ~243
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.
| Name | Type | Req | Description |
|---|---|---|---|
| foreignSales | array | – | Year-to-date foreign client income for the sales-side (§ 6i) check |
| foreignServicePurchase | string | yes | Foreign service purchases: none_confirmed = verified none, possible = maybe (e.g. runs online ads), qualifying_confirmed = a qualifying purchase from a non-CZ supplier is confirmed |
| foreignServicePurchaseConfirmedAt | string | – | – |
| purchaseDate | string | – | Date of the qualifying purchase; drives the 15-day § 97 registration deadline |
| today | string | – | Evaluation date; defaults to today |
| vatStatus | string | yes | Current VAT status of the OSVČ |
| vatStatusConfirmedAt | string | – | When the VAT status was last confirmed (freshness window 180 days) |
No output schema declared.
No examples provided.
check_thresholds Statutory income threshold monitor ~78
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.
| Name | Type | Req | Description |
|---|---|---|---|
| annualIncome | number | yes | – |
No output schema declared.
No examples provided.
compare_regimes Standard vs paušální daň comparison ~184
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.
| Name | Type | Req | Description |
|---|---|---|---|
| annualIncome | number | yes | Gross annual business income in CZK |
| deductions | object | – | – |
| flatRatePercent | – | – | Flat-rate expense percentage as a decimal: 0.4 (other business), 0.6 (most freelancers / živnost volná), 0.8 (craft trades) |
| hasChildUnder3 | boolean | – | – |
| isMarried | boolean | – | – |
| numberOfChildren | integer | – | – |
| rentalAnnualIncome | number | – | – |
| spouseIncomeUnderLimit | boolean | – | Spouse annual income under the credit limit (sleva na manžela/manželku) |
No output schema declared.
No examples provided.
compute_year Full-year OSVČ tax computation ~368
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.
| Name | Type | Req | Description |
|---|---|---|---|
| activityType | string | – | – |
| annualBusinessIncome | number | – | Exact annual business income in CZK; takes precedence over the monthly figure |
| children | array | – | – |
| citizenshipType | string | – | – |
| deductions | object | – | – |
| disabilityGrade | string | – | – |
| employerCoversHealth | boolean | – | – |
| flatRatePercent | – | – | Flat-rate expense percentage as a decimal (0.4 / 0.6 / 0.8) |
| hasChildUnder3 | boolean | – | – |
| hasReducedSocialMinimum | boolean | – | – |
| hasZTP | boolean | – | – |
| isCzechTaxResident | boolean | – | – |
| isExemptFromMonthlyZalohy | boolean | – | – |
| isMarried | boolean | – | – |
| isNewOsvc | boolean | – | – |
| isVATRegistered | boolean | – | – |
| monthlyBusinessIncome | number | – | Gross monthly business income in CZK (§ 7 ZDP) |
| publicHealthStatus | string | – | – |
| rentalMonthlyIncome | number | – | – |
| spouseIncomeUnderLimit | boolean | – | Spouse annual income under the sleva na manžela limit |
| targetRegime | string | – | Simulate a different regime without changing the stored facts |
| taxRegime | string | – | – |
| taxYear | number | – | Only 2026 is supported because the engine currently has a 2026 ruleset |
No output schema declared.
No examples provided.
convert_eur_czk EUR → CZK conversion (ČNB rate) ~79
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.
| Name | Type | Req | Description |
|---|---|---|---|
| amountEur | number | yes | Amount in EUR |
No output schema declared.
No examples provided.
czech_working_days Czech holidays and working-day shifts ~76
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.
| Name | Type | Req | Description |
|---|---|---|---|
| date | string | – | Optional date (YYYY-MM-DD) to test for working-day status |
| year | integer | yes | – |
No output schema declared.
No examples provided.
estimate_penalty Late-payment penalty estimate ~213
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.
| Name | Type | Req | Description |
|---|---|---|---|
| daysOverdue | integer | yes | – |
| dueDate | string | – | Original due date (YYYY-MM-DD); anchors the correct half-year repo rate |
| gracePeriodActive | boolean | – | – |
| obligationType | string | yes | Obligation family: health/social insurance debt, tax_advance (záloha na daň), pausal (paušální daň payment), tax_return (late filing), prehled_* (late Přehled), annual_social (doplatek) |
| owedAmount | number | yes | Outstanding amount in CZK |
No output schema declared.
No examples provided.
get_filing_deadlines DPFO filing deadline (daňové přiznání) ~129
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.
| Name | Type | Req | Description |
|---|---|---|---|
| route | string | – | Filing route: standard_deadline = paper/no extension (1 April), self_electronic_extension = filed electronically after 1 April (+1 month), advisor_extension = filed by a tax advisor (1 July) |
| taxYear | integer | yes | The tax year the return is FOR (e.g. 2025 return is filed in 2026) |
No output schema declared.
No examples provided.
get_flat_tax_band Paušální daň band lookup ~106
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.
| Name | Type | Req | Description |
|---|---|---|---|
| annualIncome | number | yes | – |
| flatRatePercent | – | – | Flat-rate expense percentage as a decimal: 0.4 (other business), 0.6 (most freelancers / živnost volná), 0.8 (craft trades) |
No output schema declared.
No examples provided.
get_prehled_deadlines Přehled deadlines (ČSSZ + zdravotní pojišťovna) ~122
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).
| Name | Type | Req | Description |
|---|---|---|---|
| route | string | – | Filing route: standard_deadline = paper/no extension (1 April), self_electronic_extension = filed electronically after 1 April (+1 month), advisor_extension = filed by a tax advisor (1 July) |
| taxYear | integer | yes | – |
No output schema declared.
No examples provided.
get_rule_source Rule citation and verification lookup ~117
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.
| Name | Type | Req | Description |
|---|---|---|---|
| locale | string | – | – |
| topic | string | yes | – |
No output schema declared.
No examples provided.
What is the cz.freelax/tax-engine MCP server?
cz.freelax/tax-engine is an MCP server listed in the public MCP registry as cz.freelax/tax-engine. Deterministic Czech OSVC tax tools for 2026: tax, insurance, deadlines, VAT and exchange rates. This page covers its hosted endpoint (https://freelax.cz/api/mcp).
Is the cz.freelax/tax-engine MCP server safe to use?
cz.freelax/tax-engine scores 79 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the cz.freelax/tax-engine MCP server expose?
cz.freelax/tax-engine exposes 14 tools: compute_year, calc_set_aside, compare_regimes, calc_flat_tax_settlement, estimate_penalty, and 9 more. Their descriptions and schemas cost roughly 2,291 tokens of context every time the server is loaded.
Does the cz.freelax/tax-engine MCP server require authentication?
No. We connected to cz.freelax/tax-engine without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the cz.freelax/tax-engine MCP server still maintained?
cz.freelax/tax-engine is still listed as active in the MCP registry. We last reached this channel on 24 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.