Integrations · MCP

Use Nefin in Claude

Add Nefin as a connector in Claude and ask about your books in an ordinary chat: who owes you, how last quarter went, or a draft invoice for a new client. It works on the web, in the desktop app and on your phone, with no terminal and no code.

Server URL

https://api-books.nefin.app/mcp

Paste this into Claude when you add the connector.

Before you start

A Claude account on any plan. Free accounts can add one custom connector; Pro, Max, Team and Enterprise can add more.
A Nefin account with two-step verification. If you haven’t set it up, Nefin walks you through it the first time you connect.
AI switched on for at least one company. An owner turns it on in Settings → Company. Claude can only reach companies where AI is on.
The Professional or Business plan in Nefin. Starter companies show up as locked, with an upgrade link.

Add Nefin to Claude

These steps are for Free, Pro and Max plans. On a Team or Enterprise plan an owner adds Nefin for everyone first. See Team and Enterprise plans.

Open your connectors

In Claude, go to Customize → Connectors and click Add custom connector. You may need to click + first.

Enter Nefin’s details

Name it Nefin and paste the server URL:

https://api-books.nefin.app/mcp

Choose how Claude signs in

What you see here depends on your account:

Name, URL and Advanced settings on one screen: leave the OAuth Client ID and Client Secret under Advanced settings empty.
A second step with sign-in options: for Authentication choose Sign in now. For OAuth client choose Register automatically.

Don’t pick “Use Claude’s published identity”. Nefin doesn’t support that option yet, so the connection fails. Register automatically works. Claude won’t let you change this after the connector is added, so if you picked the wrong one, remove the connector and add it again.

Click Add.

Connect and allow access

Click Connect next to Nefin. Nefin opens in a new window. Sign in as usual, including your two-step code. Nefin shows which companies Claude will reach and what it can do. The connection is read-only unless you turn on Allow changes, which lets Claude create and update invoices, bills, payments and journal entries. Click Allow access and you go back to Claude, where Nefin is now connected.

You only do this once. Nefin then shows up in Claude everywhere you sign in with the same Claude account: in the browser, in the desktop app and in the mobile app.

Team and Enterprise plans

An owner adds Nefin for the organization once. Each member then connects with their own Nefin login, so everyone keeps their own permissions and the audit log shows who did what.

Owner: add the connector

Go to Organization settings → Connectors.
Click Add, then Custom. If Claude asks for the connector type, choose Web.
Paste the server URL and choose the sign-in settings described in step 3 above: Sign in now and Register automatically, or leave the OAuth fields empty.
Click Add. Nefin now appears for every member with a Custom label.

Members: connect your own account

Go to Customize → Connectors and find Nefin.
Click Connect, sign in to Nefin and click Allow access.

Don’t share one Nefin login. Claude’s connector settings can also send a fixed token in request headers. Don’t put a Nefin token there. A token belongs to one person, so everyone in the organization would work as that person. Sign-in gives each member their own access.

Use it in a chat

In a conversation, click + at the bottom left, open Connectors and make sure Nefin is switched on. Then just ask:

“List my Nefin companies.”
“Which invoices in Acme Ltd are overdue, and who owes the most?”
“In Acme Ltd, run the profit and loss for last quarter and compare it with the quarter before.”
“In Acme Ltd, draft an invoice for Bardhi SHPK: 10 hours of consulting at 45.00, standard VAT.”
“In Acme Ltd, show me every bill from Bardhi SHPK this year and the total we paid.”
“Get Nefin's guide for bank statements, then reconcile this statement for Acme Ltd.”
“Get Nefin's guide for payroll, then show me last month's payroll run in Acme Ltd.”

Name the company in your request

Start with the company, such as “in Acme Ltd, …”. If you have only one company, Claude picks it for you. If you have several and don’t say which, Claude asks you before it does anything.

Every answer says which company it used and links to the record in Nefin, so you can check it in one click.

Ask for the workflow first

Bigger jobs take several steps in a fixed order. Nefin keeps those steps in short guides that Claude reads on demand with the get_guide tool. Nefin tells Claude to fetch one before bank statement, payroll or tax payment work, and you can ask for one yourself. Claude then follows the guide instead of guessing the order. The guides are:

bank_statements: importing a bank statement and reconciling it
payroll: running payroll
tax_payments: paying income tax, pension, VAT or a tax debt
errors: what to do when Nefin refuses something

For example: “Get Nefin’s guide for bank statements, then reconcile this statement for Acme Ltd.”

Amounts come back as exact decimals, so nothing gets rounded along the way.

What Claude can do

Nefin gives Claude 26 tools. Each one works in one company at a time, so name the company in your request. With one company Claude uses it automatically. With several, Claude asks which one you mean.

Read

Never changes anything.

list_companies	See the companies you can work in and your role in each
get_guide	Read the step-by-step guide for a bigger job, such as a bank statement or payrolltopic: bank_statements · payroll · tax_payments · errors
run_report	Run a financial report, such as profit and loss, balance sheet or agingtype: trial-balance · profit-loss · balance-sheet · aging-receivable · aging-payable · general-ledger · tax-summary · cash-flow · budget-vs-actuals · cash-projection · sales-book · purchase-book
search_records	Find a contact, document, item or account by name or number
list_contacts	List customers and vendors with what they owe or are owed, or open onetype: customer · vendor
list_documents	List invoices and bills, or open one with its lines and paymentsdocType: invoice · bill
list_setup	List your accounts, items, VAT rates and stock levelskind: account · item · vat_rate · stock_level
list_journals	List journal entries, optionally for a date range or status
list_payments	List payments received and paid, including drafts waiting to be connected
list_bank_accounts	List your bank accounts with their balances and open statement lines
list_bank_transactions	List imported bank statement lines and whether each one is matched
get_bank_reconciliation	Check a bank account against its statement and see what explains the difference
get_payroll	Read salaries, adjustments, payroll runs and payslips, or calculate a salary

Create and update drafts

Records and drafts. Nothing reaches the ledger yet.

save_contact	Add a customer or vendor, or update an existing onetype: customer · vendor · both
create_setup	Add a ledger account, an item or a VAT ratekind: account · item · vat_rate
create_document	Create a draft invoice or billdocType: invoice · bill
import_bank_statement	Import bank statement lines for matching; nothing is posted yet
set_salary	Set or change how an employee is paid

Post, correct or delete

Flagged as destructive, so the AI app should confirm with you first.

update_document	Change an invoice or bill; new lines on an activated one reverse and re-post its entrydocType: invoice · bill
delete_document	Delete a draft or void invoice or billdocType: invoice · bill
activate_document	Finalize a draft invoice or bill and post it to the booksdocType: invoice · bill
record_payment	Record a payment received or paid and apply it to invoices or bills
manage_journal	Create a manual journal entry as a draft, or post a draft to the books
reconcile_bank_lines	Book imported statement lines as payments, transfers, fees or journal entries
mark_bank_period_reconciled	Mark a bank account as reconciled up to a statement date and lock that period
run_payroll	Create, approve and pay a payroll run, and manage recurring payroll adjustments

Tools that were renamed

Old names keep working for now, so saved prompts and scripts don’t break. Permissions and allowlist entries belong to a tool’s name, so set them again on the new tool.

get_contact → list_contacts
get_document → list_documents
list_accounts → list_setup
list_items → list_setup
list_vat_rates → list_setup
list_stock_levels → list_setup
list_draft_payments → list_payments
create_contact → save_contact
update_contact → save_contact
create_account → create_setup
create_item → create_setup
create_vat_rate → create_setup
create_invoice → create_document
create_bill → create_document
update_invoice → update_document
update_bill → update_document
delete_invoice → delete_document
delete_bill → delete_document
send_invoice → activate_document
receive_bill → activate_document
create_journal → manage_journal
post_journal → manage_journal
connect_draft_payment → record_payment

Staying in control

Your permissions, nothing more. Claude works as you in each company. If your role can’t post journals, neither can Claude.
Everything is on the record. Changes appear in the audit log under your name.
Claude asks first. When Claude wants to use a Nefin tool, it asks for your approval. Choose Always allow only for tools that read. Keep approving the ones that post to the ledger one at a time.
Block what you don’t need. In Customize → Connectors, select Nefin and set any tool to Blocked. To let Claude only read and prepare drafts, block every tool that posts, corrects or deletes: update_document, delete_document, activate_document, record_payment, manage_journal, reconcile_bank_lines, mark_bank_period_reconciled and run_payroll.

To cut off access, go to Account → AI connectors in Nefin and click Disconnect next to Claude. It takes effect immediately. To remove Nefin from Claude as well, click Remove next to it in Customize → Connectors.

Limits in each AI app

Every AI app has its own limits. This table shows what each one means for Nefin and what to do about it. The app on this page is first.

AI app	Tool names	Long instructions	Signing in	Approving actions	After a change
Claude apps	Nothing to set. Tool names are capped at 64 characters and every Nefin tool name fits.	Nothing to work around. For a long job, ask Claude to get Nefin's guide first.	Choose Register automatically when you add the connector. Do not pick Use Claude's published identity, which Nefin does not support yet.	Set each Nefin tool to Always allow, Needs approval or Blocked in Customize, Connectors.	Start a new chat after anything changes. Each conversation keeps the tool list it started with.
Claude Code	No limit to manage for Nefin's tools.	Server instructions and each tool description are cut at 2 KB, so Nefin keeps long workflows behind get_guide. Ask Claude to get the guide before a big job.	Run /mcp, choose nefin and pick Authenticate. Where no browser can open, send a personal token in the Authorization header instead.	Claude Code asks before each tool you have not allowed. Allow the ones you trust in .claude/settings.json.	Run /mcp and reconnect nefin after anything changes. A running session keeps the tool list it started with.
ChatGPT	Nothing to set for Nefin's tools.	Nefin keeps its most important rules in the first 512 characters of its instructions and puts long workflows behind get_guide. Ask ChatGPT to get the guide before a big job.	Choose OAuth and leave the client ID and secret empty, so ChatGPT registers itself with Nefin.	ChatGPT asks you to confirm actions that change data. Nefin marks its read tools as read-only, so lookups run without a prompt.	Refresh the app in ChatGPT's connector settings after anything changes, then start a new chat.
Cursor, VS Code, Gemini CLI	Cursor loads about 40 tools across all connected servers and drops the rest. Turn off Nefin tools you don't use, or other servers. VS Code and Gemini CLI have no such cap for Nefin.	Nothing to work around. For a long job, ask the agent to get Nefin's guide first.	Add the server URL and sign in when the app opens Nefin in your browser. A personal token in the headers works in all three.	Each app asks before it runs a tool unless you told it to trust or auto-run that tool. Leave that off for the tools that post.	Toggle the server off and on in Cursor or VS Code, or restart Gemini CLI, after anything changes.
Gemini	Gemini Enterprise recommends at most 100 enabled actions per server, well above what Nefin has.	No cut-off is documented. For a long job, ask Gemini to get Nefin's guide first.	Nefin registers the app for you where the console supports it. Where it asks for a client ID and secret, register one with the command in the guide.	The connection is read-only unless you turn on Allow changes when you connect. Check what Gemini proposes before you approve a change.	Disconnect and reconnect Nefin in the app's settings after anything changes.

Troubleshooting

Connecting fails straight after I click Connect: The connector was most likely added with “Use Claude’s published identity”. Remove it and add it again with Register automatically, or with the OAuth fields left empty.
The Nefin sign-in page says AI features are not enabled: None of your companies has AI switched on. Ask an owner to turn it on in Settings → Company, then click Connect again.
Claude answers without using Nefin: Check that Nefin is switched on under + → Connectors in that chat, and mention Nefin in your question.
Claude says it can’t find a company: Claude only sees companies where AI is on and where you are an active member. Ask Claude to list your Nefin companies to see exactly what it can reach.
Claude asked which company to use: You belong to more than one company, so Claude asks before it does anything. Name one, for example “in Acme Ltd, …”. With only one company Claude picks it for you.
Claude doesn’t see a tool or uses an old tool name: A chat keeps the tool list it started with. Start a new chat after you reconnect Nefin or after Nefin adds or renames a tool.
A tool I blocked or always allowed is asking again: Those settings belong to a tool’s name. If the tool was renamed (see the renamed tools), set Blocked or Always allow again on the new tool.
I can’t add a second custom connector: Free plans allow one custom connector. Remove another one first, or upgrade your Claude plan.
Nefin asks me to sign in again: That happens if you haven’t used the connector for 30 days, or if it was disconnected in Nefin. Click Connect next to Nefin in Customize → Connectors.

Using a different AI app?

The same server works elsewhere. Nefin has a setup guide for Claude Code, ChatGPT, Cursor, VS Code, Gemini CLI and Gemini. See all of them on the integrations page.