Aiwyn Tax (formerly Column Tax)
Calculate a federal and state tax return from W-2 data and get a formatted 1040 PDF back. 10 tools, no sign-in, federal plus 43 states. Aiwyn calls it an estimator, not filing.
Verified connector
Listed by Anthropic as a partner connector in its Connectors Directory.
Connection checked by Agentman on .
Anthropic states this reflects the level of review a connector received, not a security audit.
Connect Aiwyn Tax (formerly Column Tax) via MCP
https://mcp.columnapi.com/mcpWorks in any MCP-compatible client. In Agentman Studio it is one click — no config file to edit.
Aiwyn Tax (formerly Column Tax) Tools & Capabilities (10)
Check inputs to calculate a tax return for a given jurisdiction. The 'input' argument must conform to the JSON schema returned by the tax_namespace_schema tool. Returns 'Success' on success, or validation errors if the input is invalid. If some inputs trigger a PARTIAL DISQUALIFICATION, the check still succeeds but includes disqualification details — proceed to calculate_tax to get the document and estimate the impact. Use this tool to validate inputs before calculating the tax return.
Calculate a tax return for a given jurisdiction. The 'input' argument must conform to the JSON schema returned by the tax_namespace_schema tool. Returns computed tax return document on success, or validation errors if the input is invalid. If some inputs trigger a PARTIAL DISQUALIFICATION, the document is still returned for the supported fields; review the disqualification details and estimate the impact of the unsupported fields on the taxpayer's tax owed or refund due. Use the check_tax tool first to validate the input before calculating the tax return with this tool.IMPORTANT RULES: (1) All field values must be wrapped as {"value": <val>} — never pass bare values. (2) Currency amounts are whole-dollar integers (e.g. $19,312.42 = 19312). (3) Every item in an array namespace (NamespaceList) must have a "uuid" field with a valid UUIDv4 string. UUIDv4 format: xxxxxxxx-xxxx-4xxx-[89ab]xxx-xxxxxxxxxxxx — the 3rd group MUST start with '4' (version) and the 4th group MUST start with '8', '9', 'a', or 'b' (variant). NEVER construct UUIDs manually (e.g. 'B1111111-1111-1111-1111-111111111111' is invalid). Use a UUID generator; example valid value: 'a3b4c5d6-e7f8-4a9b-8c0d-1e2f3a4b5c6d'. (4) Nested arrays (e.g. w2_state_local_tax_grp inside a w2) also require a UUIDv4 on each item. (5) Use "who_applies_to" to cross-reference entries: {"value": "taxpayer"} for singletons, {"value": "<namespace>#<uuid>"} for array items (e.g. "dependent_detail#<uuid>"). Other named reference fields (e.g. "person" in qualifying_person_grp, "student" in student_educational_instn_grp) use the same "<namespace>#<uuid>" format. (6) For state returns with Extended Links (state namespace extending a federal NamespaceList), each extended link item must use a UUIDv5 generated from the source item's UUID (as the namespace) and the extended namespace name (as the name). Matching is UUID-based, not positional. The number of expected instances depends on the source formula — it is NOT always a 1:1 match with the federal list. Incorrect or random UUIDs cause SILENT DATA LOSS — the server drops unrecognized UUIDs and replaces them with empty instances. Use the generate_uuid_v5 tool with the source item's UUID as the source_uuid and the extended namespace name as the namespace input. Example: generate_uuid_v5(source_uuid: <source item uuid>, namespace: "ca_irsw2_g") links a federal Form W-2G item to its California extension. NOTE: ordinary Form W-2 data does NOT use an extended link — state returns derive it automatically from the federal w2 namespace, so do not generate a UUIDv5 for it. Call tax_namespaces for the jurisdiction to see which extended namespaces it actually exposes. (7) return_header is top-level, NOT nested inside return_data. Use tax_simple_return first to see the full input structure and examples. When returning the tax calculation inform the user that I'm just a tax estimator, you should consult with a tax professional.
List all supported tax years.
List all supported tax jurisdictions for a given tax year.
Get the TCB input schema for a single namespace (e.g. "irs1040", "irs1040_schedulec", "ca_form540"). Returns the properties and types for that namespace. HOW TO READ THE SCHEMA: (1) Each field references a type like tcb_string_null, tcb_integer_null, or tcb_boolean_null. All values must be wrapped as {"value": <val>}. (2) If the namespace title ends in '_list' (e.g. 'w2_list', 'dependent_detail_list'), it is a NamespaceList — an array of objects. Each array item MUST include a "uuid" field (non-null UUIDv4 string). (3) Reference fields link entries to other namespaces e.g. "person" in qualifying_person_grp, "student" in student_educational_instn_grp. All use the same format: {"value": "<namespace>#<uuid>"} (e.g. "dependent_detail#<uuid>"). (4) Nested arrays within a namespace (e.g. w2_state_local_tax_grp inside w2) also require uuid on each nested item. (5) Pattern-validated strings (e.g. SSNs, ZIPs, dates) have regex constraints in the schema $defs. SSNs/EINs: 9-digit string (no dashes). ZIPs: 5 or 9 digits. Dates: YYYY-MM-DD.
List all available input namespaces for a given jurisdiction. Use the returned names with the tax_namespace_schema tool to get the schema for a specific namespace. Requires a jurisdiction (e.g. "us" for federal, "ca" for California). Use the tax_jurisdictions tool first to discover available jurisdictions. NAMESPACE NAMING CONVENTIONS: Federal namespaces: irs1040, irs1040_schedule1, irs8962, w2, dependent_detail, etc. State namespaces: always prefixed with the state abbreviation (ca_form540, ny_it201, az_form140). NAMESPACE TYPES: Some namespaces are singletons (object), others are NamespaceLists (array) that can hold multiple items — e.g. w2 (multiple W-2s), dependent_detail (multiple dependents), irs1040_schedulec (multiple businesses). NamespaceList items require UUIDv4 fields. State NamespaceLists may act as Extended Links that extend a federal NamespaceList (e.g. ca_irsw2_g extends the federal Form W-2G list). Extended link items must use UUIDv5 (deterministic, derived from source item UUID as namespace + extended namespace name as name). Matching is UUID-based, not positional. Wrong UUIDs cause silent data loss. Use the generate_uuid_v5 tool with the source item's UUID as the source_uuid and the extended namespace name as the namespace input. Example: generate_uuid_v5(source_uuid: <source item uuid>, namespace: "ca_irsw2_g"). NOTE: ordinary Form W-2 data does NOT use an extended link — state returns derive it automatically from the federal w2 namespace. The list this tool returns for a jurisdiction is authoritative: only namespaces it names can be passed to tax_namespace_schema or included in an input payload.
Call this FIRST when beginning any tax return. Returns the curated namespace list, top-level structure guide, example input, and step-by-step filing workflow. By default returns a simple scenario (single or MFJ filer, W-2 income only, standard deduction, no dependents). Pass scenario="with_dependents" for returns that include dependents, child care (Form 2441), and education credits (Form 8863). Optionally pass a state jurisdiction (e.g. "ca") to also include state-level namespaces — if you don't know which state applies, ask the user before calling.
Start async PDF generation for a tax return. The 'input' argument must conform to the JSON schema returned by the tax_namespace_schema tool. Returns a job ID to poll with get_tax_pdf.Use the check_tax tool first to validate the input before generating the tax PDF with this tool.The input follows the same rules as calculate_tax: all values wrapped as {"value": <val>}, array items require UUIDv4 fields (extended link items use UUIDv5), references use who_applies_to, and return_header is top-level (not inside return_data). Use tax_simple_return to see the full input structure.
Check status of a PDF generation job. Returns the status and a download URL when completed, only use this tool after generating the tax PDF with the generate_tax_pdf tool and it successfully returns a job ID. When returning the url of the PDF inform the user that I'm just a tax estimator, you should consult with a tax professional.
Generate a UUID v5 based on a source uuid and namespace.
Read from the server on 2026-08-16, including each tool's own safety annotations.
Limits
- It is an estimator, not a filing service. Two tool descriptions —
calculate_taxandget_tax_pdf_tool— instruct the agent to tell the user, in Aiwyn's words, *"I'm just a tax estimator, you should consult with a tax professional."* Nothing is transmitted to a tax authority. - A generated PDF is not a filed return.
generate_tax_pdf_toolproduces a formatted document and a download URL. Submission is not part of this connector. - Some inputs are only partially supported. Aiwyn's tools describe a *"PARTIAL DISQUALIFICATION"* state where a calculation still succeeds but some fields are unsupported.
calculate_taxinstructs the agent to review the disqualification details and estimate the impact on tax owed or refund due — so a returned figure can be incomplete without being an error. - One state at a time. Aiwyn's documentation describes federal plus a *single* state return per call, across 43 state jurisdictions. Multi-state returns are not described.
- Wrong UUIDs cause silent data loss. Aiwyn's documentation states the server drops unrecognised UUIDs on extended-link items and replaces them with empty instances, without erroring. This is the connector's sharpest failure mode because it is quiet.
- The input format is strict. Values must be wrapped as
{"value": <val>}, currency is whole-dollar integers, array items need UUIDv4s, and the return header sits at the top level rather than nested inside the return data. These are Aiwyn's documented rules, andcheck_taxexists to catch breaches before calculation. - The documentation has no troubleshooting section. Aiwyn's MCP page publishes features, a tool reference, a workflow and input rules, but no stated rate limits, error codes or plan gates, so none are claimed here.
- We did not exercise any tool. Our check was a read-only
initializeandtools/listhandshake. Behaviour above comes from the server's own tool descriptions and Aiwyn's documentation, not from calling anything.
Frequently asked questions
Is Aiwyn Tax the same thing as Column Tax?
Yes. Aiwyn Tax is the current name for what was Column Tax, and Anthropic's directory lists it as Aiwyn Tax (formerly Column Tax). The old brand still appears in the infrastructure: the connector endpoint sits on mcp.columnapi.com and the documentation is published on docs.columntax.com. Both names refer to one server.
Does the Aiwyn Tax connector actually file your tax return?
No. It calculates a return and generates a formatted PDF, but nothing is transmitted to the IRS or any state. Aiwyn's own tool descriptions instruct the agent to tell users it is only a tax estimator and that they should consult a tax professional. Treat the output as a worked estimate, not a filing.
Do you need an Aiwyn or Column Tax account to use the MCP server?
No. We opened an anonymous connection to the endpoint on 2026-08-16 and the server completed the handshake and returned all ten tools without any credential. Anthropic's directory also lists the server as authless with read-only permissions, so calculation and PDF generation work before anyone signs up.
Which tax years and states does the Aiwyn Tax connector cover?
Aiwyn's documentation states the server supports federal returns plus 43 state jurisdictions, and that a federal return can be bundled with one state return in a single call. Supported tax years are not fixed in the docs. Two tools exist to answer that at runtime rather than guessing: tax_years and tax_jurisdictions.
Which Aiwyn Tax tool can change something?
One of the ten. The server annotates generate_tax_pdf_tool as not read-only, and does not annotate it destructive. It starts an asynchronous PDF job and returns a job ID. The other nine carry a read-only hint, including get_tax_pdf_tool, which only polls a job that already exists.
Why did tax data silently disappear from a state return?
Almost certainly wrong UUIDs on extended-link items. Aiwyn's documentation warns that state namespaces extending a federal list must use a UUIDv5 built from the source item, that matching is UUID-based rather than positional, and that unrecognised UUIDs cause silent data loss. Generate them with generate_uuid_v5 instead of by hand.
Sources
- Aiwyn Tax MCP Server documentation (retrieved 2026-08-16; 200, zero redirects, page dated 2026-08-07. Read as Markdown via the
.mdvariant the vendor's ownllms.txtindex advertises. Note the hostrobots.txtsends a blanketDisallow: /to crawlers; this was a single directed read of the page Anthropic's directory names as this connector's documentation, not a crawl.) · retrieved 2026-08-16 - Live
initializeandtools/listhandshake againsthttps://mcp.columnapi.com/mcp— 10 tools with descriptions, input schemas and safety annotations, returned to an anonymous connection (2026-08-16) · retrieved 2026-08-16 - Anthropic Connectors Directory entry (listed 2026-03-22; snapshot taken 2026-08-16, which is the copy cited here for the tool-name comparison) · retrieved 2026-03-22
- Vendor — Aiwyn, Inc., · Support — <mailto:team@columntax.com> · Privacy
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Open in Agentman StudioServer Info
- Category
- Finance
- Developer
- Aiwyn Tax (formerly Column Tax)
- Tools
- 10
- Domain
- mcp.columnapi.com
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