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@casys/mcp-erpnext

[!IMPORTANT] Installing the 3.1 beta: for npm/Node use npx -y @casys/mcp-erpnext@next; for Deno use deno run -A jsr:@casys/mcp-erpnext@^3.1.0-beta/server. Both follow the current prerelease — JSR has no dist-tags, hence the range there. Exact versions are in the CHANGELOG. The beta adds the generic document viewer and attachment workflows, so test it with the MCP host your users actually run before replacing a stable deployment.

Let any MCP-compatible AI agent operate your ERPNext / Frappe instance — documents, workflows, and interactive viewers inside the host (Claude Desktop, Claude Code, VS Code Copilot, or custom).

Works with self-hosted and ERPNext Cloud (frappe.cloud) instances.

Built on @casys/mcp-server — the MCP server framework (concurrency, auth, MCP Apps, observability) that powers this project.

Screenshots

Interactive viewers rendered inside an MCP host, driven entirely by tool results.

What’s New

See the CHANGELOG for the full release history, or the latest release for the current version’s highlights.

3.1 beta preview: the beta keeps the 3.0 tool surface and adds a generic document viewer, child tables, document attachments, in-view navigation, and active context. 3.1.0-beta.11 adds reversible context selection, compact Kanban details with distinct Timesheet counts, exact selected-document navigation, five more host languages, and correct generic Company columns. It also retains bounded metadata for unpriced Buy lines and adds offline demo import plans. Features remain capability-gated by the MCP host; Buy evidence does not purchase or qualify a live ERP.

Documentation

Organised by what you are doing, following Diátaxis:

Quick Start

Prerequisites

Generate API credentials in ERPNext:

1. Login to ERPNext → top-right menu → My Settings
2. Section API Access → Generate Keys
3. Copy API Key and API Secret

Claude Desktop / Claude Code (npm)

{
  "mcpServers": {
    "erpnext": {
      "command": "npx",
      "args": ["-y", "@casys/mcp-erpnext"],
      "env": {
        "ERPNEXT_URL": "http://localhost:8000",
        "ERPNEXT_API_KEY": "your-api-key",
        "ERPNEXT_API_SECRET": "your-api-secret"
      }
    }
  }
}

Works with ERPNext Cloud — set ERPNEXT_URL to your Frappe Cloud URL (e.g. https://mycompany.erpnext.com or https://mysite.frappe.cloud). API key authentication works the same way on self-hosted and cloud instances.

VS Code Copilot

Add to .vscode/mcp.json:

{
  "servers": {
    "erpnext": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@casys/mcp-erpnext"],
      "env": {
        "ERPNEXT_URL": "http://localhost:8000",
        "ERPNEXT_API_KEY": "your-api-key",
        "ERPNEXT_API_SECRET": "your-api-secret"
      }
    }
  }
}

Deno (stdio)

{
  "mcpServers": {
    "erpnext": {
      "command": "deno",
      "args": ["run", "--allow-all", "server.ts"],
      "env": {
        "ERPNEXT_URL": "http://localhost:8000",
        "ERPNEXT_API_KEY": "your-api-key",
        "ERPNEXT_API_SECRET": "your-api-secret"
      }
    }
  }
}

HTTP mode

For a shared, always-on server rather than one process per client: how to run the HTTP server. Note it is breaking for pre-2026 HTTP clients in 3.0.0.

Category filtering

Load only the categories you need:

npx -y @casys/mcp-erpnext --categories=sales,inventory

Fresh Instance Setup

A blank ERPNext instance has no master data, so business tools fail validation until it exists. See Seed a blank ERPNext instance.

UI Viewers

Nine interactive MCP Apps viewers, registered as ui://mcp-erpnext/{name}:

Navigation and active context

Viewers progressively select the best interaction supported by the host:

• serverTools opens typed list, record, and chart targets inside the current viewer through app.callServerTool(). Back and breadcrumb navigation restore the state of each level.
• downloadFile lets the host confirm and save an attachment returned as a bounded embedded resource. The viewer never opens an ERPNext file URL directly.
• updateModelContext lets chart, KPI, and funnel selections join a bounded active-context snapshot. The compact context chip keeps up to eight items and lets users remove one item or clear them all. The snapshot contains selected values, never hidden instructions for the model.
• message.text keeps app.sendMessage() as a conversational fallback when direct navigation or context replacement is unavailable.
• Without these capabilities, local inspection remains available and unsupported remote actions are omitted.
• The Buy evidence viewer is recorded-session only. It does not call server tools, refresh live documents, or mutate ERP state.

The server supplies typed navigation metadata and the exact _availableTools allowed for each viewer, so category-filtered deployments do not expose tools that are not loaded.

Refresh model

Read-only viewers revalidate on focus and through their refresh control. Mutations use an explicit read-only request to fetch committed state; a mutating tool is never replayed automatically. Overlapping or stale responses are ignored when a newer host payload or mutation has already won. A confirmed document change marks every potentially derived snapshot in the current navigation stack as stale; each marker is removed only when that surface has actually been read again. Separate MCP Apps are not synchronized automatically in the 3.1 beta.

Building UI viewers

cd src/ui
npm ci
node build-all.mjs

Buy evidence capture

One read-only tool and one recorded App. They do not purchase, create a BOM/RFQ/PO, refresh live documents, replace generic ERP viewers, or qualify a live ERPNext instance.

• Tool: erpnext_buy_capture. Closed DocTypes only (Item, BOM, Item Price, Supplier Quotation, Supplier, Price List, UOM, Currency Exchange). Two skipCache reads must agree on modified and the closed projection fingerprint. Return is ephemeral canonical JSON + SHA-256 + byte count. The caller cannot pass sourceInstance, URL, credentials, capturedAt, or a digest. Digital Thread stores those bytes in its own CAS; this server does not keep a second CAS.
• App: io.casys.mcp-erpnext.buy-evidence 3.1.0-beta.11, resource ui://mcp-erpnext/buy-evidence-viewer (text/html;profile=mcp-app), manifest ui://mcp-erpnext/buy-evidence-manifest (application/json), acceptedActions = viewer.session.apply only. Complete, partial, unresolved, and unavailable projections stay labelled. No live DocViewer refresh, mutation, or app.callServerTool. Session anchor is the sealed Digital Thread artefact (provenance.bundleRef), not a hash of the displayed projection.
• Schemas: io.casys.mcp-erpnext.buy-source-capture/1.0, io.casys.mcp-erpnext.buy-recorded-result/1.0 and /2.0, io.casys.mcp-erpnext.buy-recorded-session/1.0.
• Result /2.0 carries bounded excludedLines metadata for selected lines absent from priced lines: exact line ID, quantity, unit, and stated reason. It carries no amount, currency, or price source; covered subtotals remain sealed values and unresolved lines remain visible.
• The viewer is built with the other MCP Apps (cd src/ui && npm ci && node build-all.mjs). Published JSR/npm artifacts include src/ui/dist/ and the Buy TypeScript module; the HTML resource and generated manifest are what a published installation serves.

Digital Thread owns configuration/seal (buy-configuration/1.0, buy-cost-bundle/1.0, buy.capture-configuration-cost@1, buy.seal-configuration-cost@1). A qualified commerce.read-erpnext-buy-source@1 binding is required before dispatch.

Tools

Record _list tools return interactive results via the doclist-viewer with row click, inline detail, and cross-viewer navigation. The attachment-specific erpnext_file_list tool does not render doclist-viewer. Generic and dedicated document reads use doc-viewer, except Sales Order, Sales Invoice, and Quotation, which retain the specialized invoice surface.

• Sales — Customers, Sales Orders, Invoices, and Quotations with full CRUD, Submit, and Cancel.
• Purchasing — Suppliers, Purchase Orders, Purchase Invoices, Receipts, and Supplier Quotations.
• Inventory — Items, Stock Balance, Warehouses, and Stock Entries.
• Accounting — Chart of Accounts, Journal Entries, and Payment Entries.
• HR — Employees, Attendance, Leave Applications, Salary Slips, Payroll Entries, and Expense Claims.
• Project — Projects, Tasks (with native assignment), and Timesheets.
• Delivery — Delivery Notes and Shipments.
• Manufacturing — BOMs, Work Orders, and Job Cards.
• CRM — Leads, Opportunities, Contacts, and Campaigns.
• Assets — Assets, Movements, Maintenance records, and Categories.
• Operations — Generic CRUD, native assignment, attachment listing, upload, host-mediated download, and deny-by-default Frappe method calls (erpnext_doc_*, erpnext_file_*, erpnext_method_call).
• Kanban — Read-write boards for Task, Opportunity, and Issue with drag-and-drop.
• Analytics — Charts (bar, area, treemap, radar, scatter, P&L…), KPIs with sparklines, and a sales funnel.
• Buy — Read-only sealed capture of closed commercial documents (erpnext_buy_capture) and an immutable recorded-session evidence viewer. Not a purchase, BOM/RFQ/PO, or live ERP qualification.
• Setup — Company creation and assignable user listing.

Full per-tool reference with parameters: docs/tools.md.

Environment Variables

MRTR is opt-in. Without this key, or when the client does not advertise elicitation, ambiguous links keep returning the existing actionable ambiguity error instead of prompting for a selection.

Do not run MRTR behind a load balancer with this configuration. The signing key proves a retry token is authentic; it does not make it single-use. That is the job of a replay store, and the default one is process-local. Share the key across two instances and the same signed retry validates on both — creating the purchase order, leave application or expense claim twice, irreversibly once submitted.

A multi-instance deployment must pass a shared atomic mrtr.replayStore to McpApp (Redis satisfies the contract with SET key 1 NX EXAT). The framework logs a warning at startup whenever MRTR is enabled without one — that warning is not noise, it is this paragraph.

Architecture

Tools are grouped by business domain under src/tools/, the Frappe REST client is dependency-free, and each UI viewer is a separate build under src/ui/. Full layout: repository layout.

npm Package

The npm package (@casys/mcp-erpnext) is a single self-contained bundle with zero runtime dependencies. UI viewers are embedded. Requires Node >= 20.

Contributing

Contributions are welcome — see CONTRIBUTING.md to get started, and AGENTS.md for the full architecture and conventions.

License

MIT

Viewers and Buy result fields use the host locale: English, French, Simplified Chinese, Traditional Chinese, Hindi, Bengali, Tamil and Urdu. Chinese script tags take precedence over region tags; zh-TW, zh-HK and zh-MO select Traditional Chinese when no script is specified. Urdu uses right-to-left document direction, and a later host locale change updates the language and direction without reloading the viewer. App-level waiting and rejection screens retain English labels in this beta; host-context support for those shared surface screens remains an upstream MCP View follow-up.