Arc & Ledger Tax Reference
Read-only US tax reference for notices, deadlines, filing screens, and clearly labeled estimates.
Open source Repository Open in the app JSON README (API)
About
Read-only US tax reference for notices, deadlines, filing screens, and clearly labeled estimates.
Details
- Kind
- MCP servers
- Topic
- Finance & crypto
- Publisher
- com.arcandledger
- Origin
- official
- Category
- ferramentas
- Transport
- http
- Version
- 0.15.1
- Last push
- 2026-07-31T01:31:24Z
- Repository state
- ativo
- Language
- TypeScript
- License
- NOASSERTION
- Added
- 2026-08-29 03:00:59
- Updated
- 2026-08-29 03:00:59
- Origin id
com.arcandledger/tax-tools
README
# Arc & Ledger Tax Help MCP server 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. | - Complete docs: https://www.arcandledger.com/mcp/ - Directory docs: https://www.arcandledger.com/mcp/directory/ - MCP privacy policy: https://www.arcandledger.com/mcp/privacy/ - Support: https://www.arcandledger.com/mcp/support/ 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. ## Connect No API key, OAuth flow, or Arc & Ledger account is required. For the reviewed educational surface, use: ```text https://mcp.arcandledger.com/directory/mcp ``` For local Claude Code testing: ```bash claude mcp add --transport http arc-ledger-tax-reference https://mcp.arcandledger.com/directory/mcp ``` The complete endpoint remains available to users who intentionally want the firm-specific public tools documented on the main MCP page. ## Directory tool set 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: - cites an official IRS or FinCEN page; - includes a shared general-information limitation; - tells the calling model to preserve exact returned figures and dates; - contains no Arc & Ledger service, contact, booking, payment, or upload link. 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. ## Privacy and safety - Tool inputs are processed in memory to answer the request. - The Worker writes no tool-call inputs, outputs, tool names, or per-call analytics to application logs. - Cloudflare Worker observability is disabled. - The server uses the request's network address temporarily as a rate-limit key. It is not written to application storage or paired with the tool body. - There is no MCP request database, user history, tax-return store, or document upload surface. - Users are instructed not to send SSNs, ITINs, EINs, tax account numbers, bank details, passwords, or documents. - All tools carry `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. ## Claude plugin `plugin/` is a Claude plugin bundle that points to the directory endpoint and adds two procedural Skills: - `respond-to-your-irs-notice` - `resolve-back-taxes` The 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`. ```text /plugin marketplace add Bgenc48/arc-ledger-mcp /plugin install arc-ledger-irs@arc-ledger ``` ## Architecture - Stateless Streamable HTTP JSON-RPC handler, with no sessions or Durable Objects. - Official `@modelcontextprotocol/sdk` protocol types and `zod` input schemas. - Two registries: the complete server in `src/registry.ts` and the restricted directory surface in `src/directory.ts`. - A 65,536-byte request-body cap, JSON content-type enforcement, batch limits, CORS handling, and per-network-address rate limiting. - Per-tool kill switch through `DISABLED_TOOLS`. - Version, tax-year, and active-tool counts exposed by `GET /version`. - Apps SDK widgets are bound only on the complete server. The directory edition exposes standard MCP results with no UI resource. ## Routes | 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. | ## Commands ```bash npm ci npm run typecheck npm test npm run dev npm run bundle-check npm run gen:products node scripts/gen-examples.mjs ``` `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. ## Layout ```text src/ index.ts Worker routes, request limits, and registry selection registry.ts Complete 21-tool and 12-prompt registry directory.ts Restricted 13-tool directory registry and output scrubber pricing.ts Adapter over the published pricing data source rates.ts Adapter over reviewed tax-year constants resources.ts Complete-server read-only resources lib/ MCP, response, rate-limit, tax, date, and schema helpers tools/ One module per tool ui/ Complete-server Apps SDK widgets plugin/ Claude plugin bundle test/ Protocol, HTTP, tax, directory, privacy, and governance tests ``` ## License Source-available for transparency and directory review. All rights reserved; see `LICENSE`.