io.
by physics-star-cat · remote · no sign-in to list tools · v1.0.0 · published by GitHub user physics-star-cat
Take-home pay after tax and social contributions for nine countries, with tax year.
1 tool: 1 do something that can't be undone.
Scanned Oct 21, 2026
- Deletes or cancels0Claude Code: deny
- Can't be undone1Claude Code: ask: see these tools
- Changes things0Claude Code: ask
- Only reads0Claude Code: allow
1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.
claude mcp add --transport http databutler-tax https://databutler.dev/api/mcp/taxFindings
Matches of fixed checks, with the text they matched.
- Warntake_home_pay
The server marks "take_home_pay" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
What this check looks forMatched text
annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The name "take_home_pay" says "pay": a word that usually means money moves, which cannot be taken back.
Tools
Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.
1 tool
Can't be undone 1Claude Code: ask
take_home_payNet salary after income tax and social contributions for an employee in one of ten countries (uk, us, ca, au, in, br, pl, fr, de, es), computed live by the LifeByNumbers salary cal…Reads text others write1 finding
Why it is in this group
- The name "take_home_pay" says "pay": a word that usually means money moves, which cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Findings
- Warn
The server marks "take_home_pay" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
What this check looks forMatched text
annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The name "take_home_pay" says "pay": a word that usually means money moves, which cannot be taken back.
Description, as the server wrote it Net salary after income tax and social contributions for an employee in one of ten countries (uk, us, ca, au, in, br, pl, fr, de, es), computed live by the LifeByNumbers salary calculators (same operator). Takes a gross salary in local currency (annual by default, or monthly with period) and a country code, plus optional state and filingStatus for the US, province for Canada, region (england|scotland) for the UK. Returns gross, net and total deductions (each annual and monthly), a line-by-line breakdown typed as tax / social / contribution / repayment, effectiveRate, the tax year the figures apply to, currency, the assumptions behind the estimate and the upstream calculator page as source. Spain (es) is listed but answers covered:false because lifebynumbers.net computes it client-side only.
Annotations the server declares
- title: Take-home pay
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.
Exfil surface
Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.
No private-data, untrusted-input, outbound path in this server alone: no tool is tagged private-data or outbound.
- Reads private data0
- Reads files, mail, messages, databases, secrets, calendars or repositories.
- Reads text others write1
- Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
- Can send data out0
- Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.
Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.
Remote posture
What anyone on the internet sees at the remote endpoint: an anonymous initialize and tools/list, and the public OAuth metadata.
Looked at Oct 22, 2026, 15:20 UTC, unchanged since Oct 22, 2026. No credentials were sent and no tool was called. What is looked at.
- Reachable
- yes
- HTTP status of an anonymous initialize
- 200
- tools/list served without credentials
- yes
- Tools that change things, listed without credentials
- 1
- Protocol version
- 2025-06-18
- WWW-Authenticate on 401
- not observed
- resource_metadata in WWW-Authenticate
- none
- RFC 9728 protected resource metadata
- none
- Authorization servers
- none
- Legacy HTTP+SSE transport
- no
- Dynamic client registration
- not observed
- Client ID metadata documents
- not observed
- HighThe whole server
The endpoint served tools/list without credentials, and the list has 1 tool that changes things (1 irreversible). Whether a call also works without credentials was not tested: tools are never called.
What this check looks forMatched text
https://databutler.dev/api/mcp/tax: tools/list returned 1 tool to an anonymous client, including take_home_pay (irreversible)
Install
Pinned to version 1.0.0. Values in angle brackets are yours to fill in.
claude mcp add --transport http databutler-tax https://databutler.dev/api/mcp/taxRun in a terminal.
Claude Code permissions
Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.
{
"permissions": {
"allow": [],
"ask": [
"mcp__databutler-tax__take_home_pay"
],
"deny": []
}
}Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as databutler-tax. Review it before you use it.
Capability tags behind 1 rule
- mcp__databutler-tax__take_home_pay untrusted-input