Connect Claude and other AI agents to your books
Nidhi Books has a built-in MCP server. Give Claude, Cursor or any MCP-capable agent a personal API key and it can answer questions from your real ledger: who owes you, what you owe suppliers, what was billed last month, what your GST looks like this period. Read-only, limited to what your role can see, and included in ₹399/month.
What an agent can do
The MCP server exposes thirteen tools. Your agent picks the right one from your question, so "which customers are more than 60 days overdue?" becomes a receivables-ageing call and "what did we bill Sharma Traders in August?" becomes an invoice search.
| Tool | What it returns |
|---|---|
| whoami | Which user, organisation and role the key acts as |
| search | Customers, items and invoices matching one term, in one call |
| list_customers / get_customer | Customers, and what one customer owes right now |
| list_items / get_item | Goods and services, with stock on hand by warehouse |
| list_invoices / get_invoice | Sales invoices with line items, tax breakdown and amount due |
| list_bills / get_bill | Supplier bills with tax, TDS and what is still payable |
| list_payments | Payments actually received, by date, customer or method |
| report_receivables_ageing | Money owed to you, bucketed current / 1–30 / 31–60 / 61–90 / 90+ days |
| report_gst_summary | Your GST position for a period, in the shape of GSTR-3B |
How to connect
- In Nidhi Books, open Settings → Account → API keys, name the key and pick an expiry (30, 90 or 365 days). Copy it; it is shown once.
- Add the server to your MCP client. The endpoint is
https://books.399apps.com/mcpand the key goes in anAuthorization: Bearerheader. - Ask the agent to call
whoamifirst. It confirms which organisation and role the key acts as.
Claude Code:
claude mcp add --transport http nidhi-books https://books.399apps.com/mcp \
--header "Authorization: Bearer YOUR_KEY"Cursor, or any client that reads an mcp.json:
{
"mcpServers": {
"nidhi-books": {
"url": "https://books.399apps.com/mcp",
"headers": {
"Authorization": "Bearer YOUR_KEY"
}
}
}
}
Self-hosting? The same server runs at /mcp on your own Nidhi Books domain.
What it will not do
Today the server reads Nidhi Books data only. It cannot raise an invoice, record a payment or change anything, and it does not reach the other Nidhi apps yet. We would rather say that plainly than have an agent promise you something it cannot do.
Access and safety
- One person, one organisation. A key carries its owner's role. A viewer's key sees what a viewer sees in the app, and no more.
- No cross-company reach. The organisation comes from the key, never from what the agent sends.
- Expiring, revocable keys. 30, 90 or 365 days, revoke any time, stored hashed.
- Rate limited per key and per organisation, so one runaway agent cannot slow the account down.
Common questions
Does 399Apps have an MCP server?
Yes. Nidhi Books has a built-in MCP (Model Context Protocol) server at https://books.399apps.com/mcp. Any MCP client that can send a bearer token, such as Claude Code, Cursor or Claude Desktop, can connect to it with a personal API key and query your books in plain language. It is included in the ₹399/month Nidhi Books plan at no extra cost.
What can an AI agent do with my Nidhi Books data?
Read it. The agent can search and look up invoices, supplier bills, payments, customers and items, and pull two reports: receivables ageing and a GSTR-3B-shaped GST summary. It cannot create, edit or delete anything today. Write access and the other Nidhi apps are not on the MCP server yet, and this page will say so when they are.
Is it safe to give an AI agent access to my accounts?
Each key belongs to one person and one organisation, and it can never see more than that person's role already allows in the app. The organisation comes from the key itself, not from anything the agent sends, so a key cannot reach another company's data. Keys expire after 30, 90 or 365 days, can be revoked at any moment, and are stored hashed, so the full key is shown only once.
How do I connect Claude to Nidhi Books?
Create a key in Nidhi Books under Settings → Account → API keys. In Claude Code, run: claude mcp add --transport http nidhi-books https://books.399apps.com/mcp --header "Authorization: Bearer YOUR_KEY". For Cursor or any client that reads an mcp.json, add a server with that URL and an Authorization header. Then ask the agent to call whoami first, which confirms whose books it is reading.
Does it cost extra to use Nidhi Books with AI?
No. API keys and the MCP server are part of Nidhi Books at ₹399/month with unlimited users. You pay your AI provider for your own agent as usual; 399Apps charges nothing per call.
Books your AI agent can actually read.
GST accounting with a built-in MCP server, included at no extra cost.