Aiwyn Tax (formerly Column Tax) MCP server and Claude connector: what it does, access, how to connect

Aiwyn Tax runs one hosted MCP server, also a Claude connector, that calculates US federal and state tax and builds a 1040 PDF. It needs no sign-in and has no access to firm data. Verified 21 Oct 2026.

Official remote MCP · calculation only, no writes to your systems
Claude connector · calculation only, no writes to your systems

Hosting: Remote HTTP only, hosted by Aiwyn at https://mcp.columnapi.com/mcp (the domain dates from the Column Tax name). No local server or public repo.
Auth: None. The Claude directory listing says no sign-in is required.
Read / write: Calculation only. The tools take the figures you supply, return a computed return and can generate a 1040 PDF. Aiwyn says the connector does not access firm or client systems, so there is nothing in your books for it to change.
Works with: Claude.ai and Claude Desktop (directory connector); Claude Code and other MCP clients through the remote URL.
Plan requirement: Not documented by the vendor. Aiwyn publishes no price for the server or connector.
Last changed: 2026-04-13: Aiwyn announced the connector as live in Claude
Verification: Verified 21 Oct 2026 by theFinanceStack · confidence: high

What can an agent do with Aiwyn Tax through MCP?

It calculates a US individual (Form 1040) return from figures you give it and produces a PDF of the completed forms. Aiwyn's docs list federal plus 43 state jurisdictions.

This is a stateless tax-calculation engine. It does not connect to a practice-management or tax-prep system.

What the agent does

Looks up supported years, jurisdictions and schemas.
Validates inputs.
Calculates.
Can start a PDF job and fetch its link.

Where it runs

Source	Tools
Aiwyn's docs	10
Claude directory	9 (it omits the PDF polling tool)

Good to know

Aiwyn says its engine has processed over 1 million 1040 returns.
Aiwyn's own article calls it "a low-risk way to explore" AI-supported tax work and does not present it as a production workflow.

Can

List supported tax years, jurisdictions and input namespaces, and return each input schema (tax_years, tax_jurisdictions, tax_namespaces, tax_namespace_schema)
Return a worked example and workflow guide for a simple scenario (tax_simple_return)
Validate inputs and flag errors before calculating (check_tax)
Compute federal and state tax and return the result as text (calculate_tax)
Start a 1040 PDF job and fetch its download link (generate_tax_pdf_tool, get_tax_pdf_tool)
Generate the deterministic IDs that state items need (generate_uuid_v5)

Cannot

File or e-file a return, or deliver anything to a client (per Aiwyn)
Read or change firm, client or practice-management records; Aiwyn says the connector does not access internal systems
Cover every form, scenario and jurisdiction yet; Aiwyn says coverage is still expanding
Replace CCH, UltraTax or other production tax software; Aiwyn positions it alongside them

What access does it get?

It gets no access to your systems. There is no sign-in and no OAuth scope. The server receives whatever the agent sends in its tool calls: figures you type, documents you attach, and anything the agent pulled from other connectors in the same chat.

Where	Scopes and permissions (as documented)	Admin requirement
Aiwyn Tax MCP server (remote)	No scopes. No authentication is required, per the Claude directory listing; Aiwyn's docs don't describe any. Aiwyn says firm authentication is planned for a later phase.	Not documented by the vendor. Any MCP client that supports remote HTTP servers can add the URL.
Claude connector (directory)	No scopes; the listing says no sign-in is required.	Claude Team/Enterprise: an Owner adds connectors for the organisation and may restrict Claude Code MCP servers.

How do I connect it?

In Claude, add Aiwyn Tax from the connector directory; elsewhere, add the remote URL https://mcp.columnapi.com/mcp. There is no account to create and no sign-in step.

Team/Enterprise first: an Owner or Primary Owner goes to Organization settings › Connectors › Browse connectors, selects Aiwyn Tax and clicks Add to your team.
Open https://claude.com/connectors/aiwyn-tax and click Connect, or in Claude go to Customize › Connectors and search for "Aiwyn Tax".
No sign-in is required; the connector is ready once added.
Ask Claude what it can do with Aiwyn Tax, then describe a scenario or supply test figures.

Calculation only; it cannot reach your firm's systems.

What should a finance team watch for?

The server has no sign-in, so anything you paste goes to an external service. Treat it as a calculator for test or anonymised data and keep client files out of it.

There is no sign-in, so Aiwyn cannot tie calls to a user, and Aiwyn doesn't document any logging or audit trail. Any audit record has to come from your AI client (for example Claude Enterprise audit logs).
Keep other connectors that hold client data (Drive, email, document stores) out of Aiwyn Tax sessions, or the agent may forward that data in a tool call.
Aiwyn says it "does not store firm or client data from Claude sessions" and recommends anonymised, redacted or test data. Aiwyn notes that inputs are processed within Anthropic's environment. That statement covers Claude sessions only; Aiwyn says nothing about calls from other clients (Claude Code, ChatGPT developer mode) that use the raw URL.
Column Tax's privacy policy (updated 6 Jan 2026) does not mention the MCP server or model training; read it and your AI provider's terms before sending real taxpayer data.
Coverage is partial: federal plus 43 state jurisdictions per Aiwyn's docs, and only some forms and scenarios. Check tax_years and tax_jurisdictions before relying on a result.
Aiwyn's docs say SSNs and EINs are 9-digit strings in the return header. Use dummy values for both, because the endpoint accepts calls with no authentication.
Aiwyn's docs warn that wrong IDs on list items cause silent data loss, so an input can drop out of the calculation without an error. Compare totals with your inputs.
Results are estimates for review. Aiwyn says outputs need firm review and approval, and nothing is filed.
The endpoint returned an HTTP 503 overload error during verification on 21 Oct 2026; Aiwyn publishes no uptime or rate-limit figures.

How could finance teams and accounting firms use it?

It suits questions and scenario checks on test or anonymised figures. It does not touch a ledger or a tax-prep system.

Inside a company

Estimate the federal and state tax effect of a bonus or relocation scenario with test figures, to frame a question for your tax adviser.
Compare filing-status or state scenarios side by side in plain language before a planning meeting.
Check an individual's estimated annual liability against their withholding, using test figures.
Ask the agent to explain each step of a calculation.

At an accounting firm

Run what-if scenarios on anonymised client figures before the preparer works the return in production software.
Cross-check a simple return from CCH or UltraTax by recalculating it with redacted inputs.
Generate a sample 1040 PDF for staff training or internal review, using test data.
Explore AI-assisted tax workflows in a sandbox, as Aiwyn itself frames the connector.

Treat every figure as an estimate for a qualified person to review. Production tax software stays the system of record, and real client data stays out unless your firm's policy allows it.

Want Aiwyn Tax connected to Claude for your team?

We set up the connection with a data rule (test or anonymised figures only) and a review step for every calculated result. Fixed fee.

Book a 30-minute setup call

Change log

Date	Change	Source
2026-08-07	Aiwyn Tax MCP server docs page updated; lists 10 tools, including get_tax_pdf_tool	docs.columntax.com/page/aiwyn-tax-mcp-server
2026-04-13	Aiwyn press release: connector live within Claude for 1040 calculations and scenario analysis	digital-release.wowktv.com/business/press-releases/cision/20
2026-03-26	Aiwyn article describes the connector, its limits and its data handling; firm authentication listed for a later phase	www.aiwyn.ai/resources/articles/aiwyn-claude-helping-firms-n
2026-03	Aiwyn Tax connector added to the Claude connector directory (Anthropic verified), using https://mcp.columnapi.com/mcp	claude.com/connectors/aiwyn-tax

FAQ

Is this official?

Yes. Aiwyn, Inc. publishes the server and the Claude connector, which Claude's directory marks as Anthropic verified. Aiwyn Tax is the former Column Tax, which is why the server sits on columnapi.com.

Is it free?

Aiwyn doesn't publish a price, and the Claude listing says no sign-in or account is required. Your Claude or other AI plan still applies.

Does it change data in Aiwyn Tax?

No. It calculates from the figures you supply and can generate a PDF. Aiwyn says it does not access firm or client systems, and it cannot file returns.

Is my data used to train models?

Aiwyn says it does not store firm or client data from Claude sessions. Column Tax's privacy policy doesn't address model training, so check it and your AI provider's terms, and use anonymised data.

Can my accountant use it on my behalf?

Aiwyn doesn't document delegated use. There is no sign-in and it holds no account or records of yours, so an accountant would run calculations in their own AI client. Aiwyn says outputs need firm review.

Something wrong or out of date? Tell us and we'll email you when it's fixed.

Sources

Verified by theFinanceStack, 21 Oct 2026. Vendor list on the CFO Software Market Map courtesy of Jason Staats; AI connectivity data by theFinanceStack. Not tax, compliance or financial advice.