Arc & Ledger Tax Reference

Read-only US tax reference for notices, deadlines, filing screens, and clearly labeled estimates.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Read-only US tax reference for notices, deadlines, filing screens, and clearly labeled estimates.

    How to connect

    How to connect Arc & Ledger Tax Reference to Claude

    The server address to paste into Claude settings:

    https://mcp.arcandledger.com/directory/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect Arc & Ledger Tax Reference to ChatGPT

    The server address to paste into ChatGPT settings:

    https://mcp.arcandledger.com/directory/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect Arc & Ledger Tax Reference to Cursor

    The server address to paste into Cursor settings:

    https://mcp.arcandledger.com/directory/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (13)

    Raw names from tools/list. Only developers need these.

    decode_irs_noticeUse when a user provides the code from an IRS notice or letter and wants a general explanation, the usual response window, or the next procedural step. Do not request the notice itself or any taxpayer identifier.
    check_resolution_optionsUse to screen general IRS payment and collection alternatives from a rough balance, filing-compliance status, ability-to-pay category, and coarse tax-account type when known. This is an educational fit screen, not a promise that the IRS will approve an option.
    estimate_irs_penaltyUse to estimate selected federal failure-to-file, failure-to-pay, and underpayment amounts from nonidentifying figures. The result is an estimate and does not replace an IRS account transcript.
    explain_tax_documentUse when a user names a US tax form or information document and wants to understand its purpose, common fields, or usual return treatment. Do not request or accept the document itself.
    deadline_calendarUse to return common federal filing and payment dates for a selected filer or entity type. The user must verify the date for weekends, holidays, extensions, fiscal years, and special facts.
    check_fbar_fatcaUse to screen general FBAR and Form 8938 thresholds from aggregate balance, filing status, residence, and account-count facts. Do not request account numbers, institution names, or statements.
    check_treaty_withholdingUse to explain general US withholding rules, documentation, and supported US-Turkey treaty rates for a payment category. Treaty eligibility and source rules depend on the full facts.
    check_itin_eligibilityUse to screen general ITIN reason categories, whether a return is commonly attached, and supporting-document requirements. Never request or process an actual ITIN, passport, or identity document.
    check_5472_obligationUse to screen common Form 5472 triggers for a foreign-owned US disregarded entity or corporation. The result is a general filing screen and does not prepare or file the form.
    estimate_quarterly_taxesUse to estimate federal quarterly tax payments from nonidentifying income, entity, withholding, and prior-year tax figures. Return the assumptions, safe-harbor context, and due dates.
    estimate_accountable_planUse to estimate potentially reimbursable business expenses under an accountable-plan scenario, including the split 2026 business-mileage rates. The result does not establish a plan or determine substantiation.
    estimate_augusta_ruleUse to screen the fewer-than-15-days home-rental rule under IRC 280A(g) and calculate conditional amounts. Keep the owner-side income exclusion separate from the business-side requirements for ordinary and necessary use and reasonable rent.
    estimate_rental_incomeUse to estimate a basic rental-income result from nonidentifying figures and identify the modeled depreciation, passive-loss, and personal-use limitations.