Tax facts MCP server

What it is

Every rate, threshold, cap and rule the member sites calculate with is recorded alongside the official page or instrument it came from, the exact words that page uses, the date it was read, and when it is next due for review. The connector serves those records to AI assistants. It answers lookups; it does not calculate anyone's tax, store anything a user sends beyond what is described in the privacy policy, or need an account.

Countries covered: the United States, the United Kingdom, Canada, Australia and New Zealand. The official body remains the source; the connector's job is to hand the assistant its words and its link so an answer can cite them.

Connect it to Claude

Server URL:

https://taxtools.network/mcp/tax

1. In Claude, open Customize → Connectors.
2. Choose Add → Add custom connector.
3. Name it TaxTools Network Tax Facts and paste the server URL.
4. Leave authentication on No sign-in: the data is public and the tools only read.

The server speaks MCP over Streamable HTTP and answers POST requests only, so opening the URL in a browser shows an error by design.

Use it with other MCP clients

The server is not tied to Claude. Any client that supports remote MCP servers over Streamable HTTP can use it: add a remote (HTTP) server with the URL above and no authentication. Examples for clients whose documentation describes this setup:

Claude Code

claude mcp add --transport http taxfacts https://taxtools.network/mcp/tax

VS Code (Copilot agent mode), .vscode/mcp.json

{ "servers": { "taxfacts": { "type": "http", "url": "https://taxtools.network/mcp/tax" } } }

Cursor, ~/.cursor/mcp.json

{ "mcpServers": { "taxfacts": { "url": "https://taxtools.network/mcp/tax" } } }

OpenAI Codex CLI, ~/.codex/config.toml

[mcp_servers.taxfacts]
url = "https://taxtools.network/mcp/tax"

Gemini CLI

gemini mcp add --transport http taxfacts https://taxtools.network/mcp/tax

Client settings change between versions; if one of these no longer matches, follow that client's own MCP documentation for a remote HTTP server without sign-in. The answers are the same whichever client asks, and the same terms and rate limits apply.

Tools

All four tools are read-only.

find_tax_facts

Searches one country's facts by words such as "standard deduction" or "personal allowance", optionally for one tax year, and returns up to ten matches with their id, value, tax year and status. Search results carry no quotes; fetch a fact for its source.

get_tax_fact

Returns one fact by id: its value, tax year, status, the official source's URL and words, the source type (statute, regulation, agency guidance…), when it was verified, when it is next reviewed, what changes it, and the member-site pages that use it.

check_tax_claim

Checks a statement against wrong versions of a rule that have been found and corrected before. It answers contradicted, with the correct fact and its source, or no known contradiction, with related facts to compare. It never confirms that a statement is correct.

get_upcoming_changes

Lists one country's facts whose review date falls in a window of up to 18 months, grouped by the release that moves them or by month, with a count per month and an optional topic filter. A review date is when a successor value is expected, not a promise that it changes then.

Prompts

Three prompts appear in the client's slash menu. Each takes a country (au, ca, nz, uk or us), runs one of the read-only tools above and asks for the source URL in the answer.

tax_fact_with_source

A figure or rule by topic, with an optional tax year, quoted with its official source.

check_tax_statement

A statement checked against recorded corrections.

upcoming_tax_changes

Facts due for review in the next 12 months, with an optional topic.

How to read an answer

• status is current, or due-for-review once a fact has passed its review date and may have changed since it was last verified.
• tax_year is written as the country writes it (2026, 2026-27). A fact with no year is a standing rule, verified as in force on its verification date; earlier years are not claimed. An older year that has a newer one says so in later_year.
• kind separates official figures from projections, figures carried forward until the official one is published, and figures derived from others. Each non-official kind says how it was arrived at.
• not_in_kb means nothing matched. The connector never substitutes a nearby figure.
• Only official sources are served. Figures the member sites quote from non-government pages (party policy statements, think tanks) stay on those pages and are not returned here.

How the data is kept current

The connector reads the same records the member sites are built from, and it picks up a new version within minutes of a site publishing one. Each record carries its own review date; the process behind it is set out in the methodology, and errors are handled under the corrections policy.

Limits

Lookups are capped per request so the connector answers questions rather than exporting the dataset, and heavy automated use from a single address is rate-limited. Use is covered by the terms of use. Answers are general information, not tax advice.

Early access to a paid tier

The connector described above is free and live. A paid tier is planned and not available yet: there is nothing to buy today. As currently planned it would add an API key, higher limits, and a change feed that sends a webhook or an email when a figure changes, with the effective date and the official source. The proposed price is US$29 per month; it may change before anything launches.

To hear when it opens, email [email protected] with the subject “Tax Facts early access” and three lines: what you are building, which countries you need, and what you use today. Joining is not a commitment, and nothing is charged. See the privacy policy for how the email is kept.

Support

Problems, wrong figures and questions: [email protected]. For a wrong figure, include the fact id and the official source that says otherwise.