ccpcrate — Canadian CCPC corporate tax

Deterministic Canadian CCPC rate stack: small business deduction and grinds, Part IV, RDTOH.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Deterministic Canadian CCPC rate stack: small business deduction and grinds, Part IV, RDTOH.

    How to connect

    How to connect ccpcrate — Canadian CCPC corporate tax to Claude

    The server address to paste into Claude settings:

    https://ccpcrate.ca/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 ccpcrate — Canadian CCPC corporate tax to ChatGPT

    The server address to paste into ChatGPT settings:

    https://ccpcrate.ca/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 ccpcrate — Canadian CCPC corporate tax to Cursor

    The server address to paste into Cursor settings:

    https://ccpcrate.ca/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 (4)

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

    ccpcrate_resolveCompute the federal Part I / Part IV / refundable / RDTOH / dividend-refund lines and the provincial layer for one CCPC and one taxation year. Returns a readable summary plus the structured result: lines (rounded, as printed), unrounded audit values, facts, warnings, layers, balances carried forward, the inputs still missing, engine and rules versions and a request hash. Deductions are negative, taxes positive. A missing required input is an error, not a default. Paid: 0.25 USD per call in USDC over x402 (Base); without a payment the call returns the x402 payment requirements.
    ccpcrate_groupCompute a whole associated group (s.256) in one call: federal line 417 as the sum of the members' prior-year adjusted investment income, the Schedule 23 allocation of the business limit, and every member's return in payer-before-recipient order so that a connected dividend's Part IV under s.186(1)(b) is filled in from the payer's own refund instead of being asked for. Returns each member's lines plus what the grind costs the group and which member causes it — the case a single-corporation computation cannot show. 0.25 USDC covers the group and its first 2 computed members, then 0.05 per additional member, never more than 1. Members that only contribute line 417 are free.
    ccpcrate_explainFree diagnostic pass over the same input as ccpcrate_resolve: which layers run, the defaults the engine would apply, every warning with its meaning (grind binding, provincial asymmetries, missing inputs), the rule rows in force for the year with sources and verification status, the open verifications, and what the paid computation would return. Contains no computed amounts — the numbers are in ccpcrate_resolve.
    ccpcrate_rulesThe statutory rates and parameters the engine uses (14 jurisdictions, effective dates, application modes, sources, verification status), filterable by jurisdiction, key and date. Free.