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Tallyfern Rates (Canada)

com.tallyfern/ratestallyfern.comstreamable-httpv0.2.0Scanned

Read-only Canadian GST/HST rates, small-supplier check and CRA allowance rates, with CRA sources.

5 tools: 5 change things.

Tools: 0 delete, 0 irreversible, 5 write, 0 read.
  • Reads private data · 0
  • Reads text others write · 0
  • Can send data out · 0
  • 1 finding

Tools listed without sign-in. Remote posture

Anlyon alternative

5 of these tools change something. Run those as governed actions.

Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.

Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.

Import an OpenAPI spec →

Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

5 tools

Changes things 5Claude Code: ask
  • cra_automobile_allowance_rateCRA reasonable per-kilometre allowance rates for employer-paid vehicle allowances (2026 default; 2025 also available): first 5,000 km and after, provinces vs territories.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    CRA reasonable per-kilometre allowance rates for employer-paid vehicle allowances (2026 default; 2025 also available): first 5,000 km and after, provinces vs territories. Optionally calculates the allowance for a number of business kilometres.

    Annotations the server declares

    • title: CRA automobile allowance rate
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • cra_meal_travel_allowanceCRA simplified-method rates (latest published tax year): flat meal rate per meal and maximum per day, and vehicle cents/km by province or territory where travel begins.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    CRA simplified-method rates (latest published tax year): flat meal rate per meal and maximum per day, and vehicle cents/km by province or territory where travel begins. These apply to moving expenses, northern residents deductions and medical travel, not to employer per-diems. Optionally calculates amounts.

    Annotations the server declares

    • title: CRA meal and vehicle rates
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • gst_hst_rate_by_provinceCurrent GST/HST rate for a Canadian province or territory (or all 13), with the PST/QST rate CRA lists for reference.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Current GST/HST rate for a Canadian province or territory (or all 13), with the PST/QST rate CRA lists for reference. From CRA's 'Charge and collect the GST/HST' table.

    Annotations the server declares

    • title: GST/HST rate by province
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • gst_hst_small_supplier_checkApply the CRA's $30,000 small-supplier tests (single calendar quarter and four consecutive calendar quarters) to taxable revenue by calendar quarter.1 finding

    Why it is in this group

    • The description's first verb is "apply": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "gst_hst_small_supplier_check" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The description's first verb is "apply": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Apply the CRA's $30,000 small-supplier tests (single calendar quarter and four consecutive calendar quarters) to taxable revenue by calendar quarter. Says whether the person must register for the GST/HST, when they stop being a small supplier, the effective date of registration, and headroom for next quarter. Most businesses only (not charities/public service bodies).

    Annotations the server declares

    • title: GST/HST small supplier check
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • ontario_hst_basicsPlain-language basics for Ontario businesses: the 13% HST rate, the $30,000 small-supplier threshold, the 29-day registration deadline and place-of-supply rule, with CRA sources.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Plain-language basics for Ontario businesses: the 13% HST rate, the $30,000 small-supplier threshold, the 29-day registration deadline and place-of-supply rule, with CRA sources.

    Annotations the server declares

    • title: Ontario HST basics
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false

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 untrusted-input or outbound.

Reads private data0
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write0
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.

Tools listed without sign-in

Looked at Oct 22, 2026, 14:42 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
5
Protocol version
2025-06-18
WWW-Authenticate on 401
not observed
resource_metadata in WWW-Authenticate
not observed
RFC 9728 protected resource metadata
not observed
Authorization servers
not observed
Legacy HTTP+SSE transport
no
Dynamic client registration
not observed
Client ID metadata documents
not observed
  • WarnThe whole server

    The endpoint served tools/list without credentials, and the list has 5 tools that change things (5 write). Whether a call also works without credentials was not tested: tools are never called.

    Matched text

    https://mcp.tallyfern.com/mcp: tools/list returned 5 tools to an anonymous client, including gst_hst_small_supplier_check (write), gst_hst_rate_by_province (write), cra_automobile_allowance_rate (write), cra_meal_travel_allowance (write), ontario_hst_basics (write)

    What this check looks for

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • The server marks "gst_hst_small_supplier_check" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The description's first verb is "apply": a word for a change.

    What this check looks for

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

Install

Pinned to version 0.2.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http rates https://mcp.tallyfern.com/mcp
claude mcp add --transport http rates https://mcp.tallyfern.com/mcp

Run 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.

.claude/settings.json
{
  "permissions": {
    "allow": [],
    "ask": [
      "mcp__rates__gst_hst_small_supplier_check",
      "mcp__rates__gst_hst_rate_by_province",
      "mcp__rates__cra_automobile_allowance_rate",
      "mcp__rates__cra_meal_travel_allowance",
      "mcp__rates__ontario_hst_basics"
    ],
    "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 rates. Review it before you use it.

Pin

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/com.tallyfern/rates/verify?hash=ab4b1410e9d305d90ea17bd8559aa3ed7264957a4a493db125fe19e88af1a7b1" | jq -e '.changed == false'

Pinned hash ab4b1410e9d3, from Oct 21, 2026, 18:56 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/com.tallyfern/rates/changes.xml

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Badge

anlyon.dev badge for com.tallyfern/rates
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Source: MCP Registry. Synced Oct 21, 2026, 18:06 UTC.