taxcredit-engine

Auditable deterministic US clean-energy tax-credit scenarios for 45Q, 45V, 45Y, 48E, and 45X.

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What it can do

  • Calculate Tax Credit: Calculate an auditable tax-credit scenario. credit is 45Q, 45V, 45Y, 48E, or 45X. facts must contain the explicit credit-specific eligibility facts; missing facts return indeterm
  • List Rule Packs: List supported credits and the current bundled rule-pack digest.
  • Get Rule Pack: Return the bundled rules and official source metadata for one credit.

What data it sees

Do you need an account

No: the server works without sign-in

Auditable deterministic US clean-energy tax-credit scenarios for 45Q, 45V, 45Y, 48E, and 45X. Versioned IRS rule packs, exact arithmetic, eligibility flags, audit hashes, and notary-ready proof.

Try it (copy-paste): calculate_tax_credit with {"credit":"45V","facts":{"tax_year":2026,"kg_hydrogen":"1000","lifecycle_kg_co2e_per_kg_h2":"0.44","greet_version":"45VH2-GREET-2025","pwa_met":true,"produced_in_us":true,...}} → returns credit_amount_usd: "3280.00" with a reproducible audit_sha256.

Pricing: 10 free calls/day, then $2.00/calculation. Pay as a human via Stripe (create_payment → redeem_payment) or as an agent via x402 escrow: fund an escrow payable to viridis:taxcredit-engine at mcp.viridisconservation.com/escrow/mcp, then retry with payment_ref=. The 402 envelope carries full instructions.

How to connect

How to connect taxcredit-engine to Claude

The server address to paste into Claude settings:

https://taxcredit-engine--hartjustin6.run.tools

  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 taxcredit-engine to ChatGPT

The server address to paste into ChatGPT settings:

https://taxcredit-engine--hartjustin6.run.tools

  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 taxcredit-engine to Cursor

The server address to paste into Cursor settings:

https://taxcredit-engine--hartjustin6.run.tools

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 (5)

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

calculate_tax_creditCalculate an auditable tax-credit scenario. credit is 45Q, 45V, 45Y, 48E, or 45X. facts must contain the explicit credit-specific eligibility facts; missing facts return indeterminate. This is not tax or filing advice.
list_rule_packsList supported credits and the current bundled rule-pack digest.
get_rule_packReturn the bundled rules and official source metadata for one credit.
verify_tax_credit_resultVerify an engine result's audit_sha256. Pass the prior result object as JSON; any changed amount, fact, rule step, or source digest fails.
describe_agentReturn fleet-standard capabilities, version, and pricing.