Read-only US tax reference for notices, deadlines, filing screens, and clearly labeled estimates.
Copy the AI prompt to install this server into Claude Code, Cursor, or another agent β or use 1-click editor setup below.
π‘ Paste into ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows)
A public remote Model Context Protocol server for general US tax information, screening tools, estimates, and firm-specific service tools. It runs as a stateless Cloudflare Worker and requires no Arc & Ledger account or authentication.
The project exposes two surfaces:
| Edition | Endpoint | Scope |
|---|---|---|
| Complete server | https://mcp.arcandledger.com/mcp | 21 tools, 12 prompts, 4 read-only resources, and 4 optional ChatGPT cards. Some results include first-party firm or service links. |
| Directory edition | https://mcp.arcandledger.com/directory/mcp | 13 reviewed educational tools. No prompts, resources, cards, firm pricing, service matching, booking, payment, upload, purchase, or promotional handoff. |
Every result is general information, not tax advice, and creates no practitioner-client relationship. The tools do not file, transmit, sign, certify, authorize payment, or access a taxpayer account.
No API key, OAuth flow, or Arc & Ledger account is required. For the reviewed educational surface, use:
For local Claude Code testing:
The complete endpoint remains available to users who intentionally want the firm-specific public tools documented on the main MCP page.
The directory edition is the surface proposed for the OpenAI Plugins Directory and Anthropic Software Directory.
| Tool | General purpose |
|---|---|
decode_irs_notice | Explain a supported IRS notice code and usual response path. |
check_resolution_options | Screen general IRS payment and collection alternatives. |
estimate_irs_penalty | Estimate selected federal late-filing, late-payment, and underpayment amounts. |
explain_tax_document | Explain the purpose and common fields of a named US tax document. |
deadline_calendar | Return common federal filing and payment dates. |
check_fbar_fatca | Screen general FBAR and Form 8938 thresholds. |
check_treaty_withholding | Explain general withholding rules and supported US-Turkey treaty rates. |
check_itin_eligibility | Screen general ITIN reason categories without treating entity ownership as automatic eligibility. |
check_5472_obligation | Screen common Form 5472 triggers. |
estimate_quarterly_taxes | Estimate federal quarterly payments and show assumptions. |
estimate_accountable_plan | Estimate potentially reimbursable expenses, including split 2026 mileage rates. |
estimate_augusta_rule | Screen the fewer-than-15-days home-rental rule and calculate conditional amounts. |
estimate_rental_income | Estimate a basic rental-income result and modeled limitations. |
Each directory result:
The directory edition intentionally excludes firm quotations, consultations, document collection, service matching, formation-state comparisons, sales-tax nexus screens, and reasonable-compensation ranges. Those tools either have a commercial purpose, rely on changing state data, or need more professional judgment than a short deterministic screen should imply.
readOnlyHint: true, destructiveHint: false, and an
explicit openWorldHint.Cloudflare still processes ordinary request metadata as the infrastructure provider. The public privacy policy describes that boundary.
plugin/ is a Claude plugin bundle that points to the directory endpoint and
adds two procedural Skills:
respond-to-your-irs-noticeresolve-back-taxesThe Skills use only tools available on the directory edition. They lead with deadlines and filing-compliance gates, label estimates, retain official source links, request no sensitive identifiers or documents, and do not promote or sell a firm service.
The repository marketplace manifest lives at
.claude-plugin/marketplace.json.
@modelcontextprotocol/sdk protocol types and zod input schemas.src/registry.ts and the restricted
directory surface in src/directory.ts.DISABLED_TOOLS.GET /version.| Route | Purpose |
|---|---|
POST /mcp | Complete MCP surface. |
POST /directory/mcp | Restricted directory MCP surface. |
GET /healthz | Liveness. |
GET /version | Version, tax year, tool counts, and directory endpoint. |
GET /.well-known/mcp-registry-auth | MCP Registry domain proof. |
GET /.well-known/openai-apps-challenge | Exact OpenAI domain challenge when configured. |
npm run bundle-check runs a Cloudflare Worker dry deployment. The bundled
workerd binary does not support every local Windows ARM64 environment, so
the hosted CI result is the release gate when that platform limitation occurs.
Source-available for transparency and directory review. All rights reserved;
see LICENSE.
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