Overview
KLARA MCP is a server built on the open Model Context Protocol (MCP), operated by ePost Service Ltd. It connects MCP-capable AI assistants – such as Claude or ChatGPT – to your KLARA company. The assistant can search and maintain customers and articles, create invoices with line items and recipients, record bookings with receipts, and add variable salary items to open payslips.
- Server address:
https://mcp.klara.ch/mcp - Transport: Streamable HTTP · Login: OAuth 2.0 with your personal KLARA API key
- 34 tools across four areas, see Available tools
Connect
Step 1 for every client: create an API key in KLARA. In KLARA, under Users, create a new API key. Give it only the roles you actually need – KLARA MCP reaches exactly what the key's role opens. Login works exclusively with an API key; enter your KLARA password only on KLARA itself, never anywhere else.
Connect with Claude
- In Claude, go to Settings → Connectors, choose Add custom connector and enter
https://mcp.klara.ch/mcp– or pick the KLARA entry in the connector directory. - Claude opens the KLARA MCP login page: paste your API key and connect.
Connect with ChatGPT
- Open chatgpt.com/plugins and click the plus “New plugin”. Enter the address
https://mcp.klara.ch/mcp. - On first connection the KLARA MCP login page opens: paste your API key and connect.
Start with the prompt “KLARA whoami” – the assistant then shows which company you're connected to and which areas your role opens.
Examples
Typical requests to your AI assistant look like this (all details are made up):
Capabilities
| Area | What the assistant can do | Access |
|---|---|---|
| Customers & articles | Search, create and update: customers with addresses, contacts, UID and VAT number; articles with prices, VAT and images; categories and filters. | Read Write |
| Invoices & orders | Create invoices with line items and recipients and fetch them as PDF; delivery via email, ePost, eBill or print; look up order documents. | Read Code |
| Accounting | Record manual bookings with receipts, look up the chart of accounts and VAT catalogues, read open bank-reconciliation positions and VAT reports. | Read Code |
| Payroll | Browse the employee directory and add variable salary items (hours, allowances, bonuses) to open payslips. | Read Code |
The confirmation gate
Everything irreversible runs in two steps: the assistant prepares the action and shows you a summary with a one-time confirmation code. Only when you provide the code is it executed – and each action exactly once. This always applies to: deletions, creating and sending invoices, bookings, receipts, salary items, number counters, company master data and subscriptions. Unconfirmed preparations expire on their own after 30 minutes.
Available tools
KLARA MCP provides 34 tools. Read only retrieves data, Write executes directly, Code requires your confirmation with the one-time code.
Context and reference data
| Tool | Purpose | Access |
|---|---|---|
klara_whoami | Connected company, login type and which areas your role opens | Read |
klara_reference_data | Chart of accounts, VAT catalogues and cases, booking types, templates, bank accounts, exchange rates, cities, article categories and filters | Read |
Customers and articles
| Tool | Purpose | Access |
|---|---|---|
klara_search_customers | Search customers by name, email, phone or customer number | Read |
klara_get_customer | One customer in detail, optionally with contacts and additional addresses | Read |
klara_search_articles | Articles via full-text search or list by product type | Read |
klara_article_details | One article with variants, set items and image | Read |
klara_lookup_articles | Articles by article numbers or as a resolved variant list | Read |
klara_prepare_customer | Create or update a customer – including UID, VAT and commercial register number | Write Delete: code |
klara_prepare_customer_contact | Create or update a customer's contact person | Write Delete: code |
klara_prepare_customer_address | Create or update a customer's additional address | Write Delete: code |
klara_prepare_article | Create or update an article – including VAT type, case and code | Write Delete: code |
klara_prepare_articles_bulk | Create several articles in one call | Write |
klara_prepare_article_catalog | Create and update article categories and filters, assign them to articles | Write Delete: code |
klara_prepare_article_image | Add or replace an article image (PNG/JPEG) | Write Delete: code |
Invoices and order documents
| Tool | Purpose | Access |
|---|---|---|
klara_get_invoice | One invoice with recipient, line items and booking status | Read |
klara_recent_invoices | Log of invoices created through KLARA MCP (the KLARA API has no invoice list) | Read |
klara_invoice_pdf | Fetch the invoice as PDF and extract its text | Read |
klara_order_documents | Look up order documents and read the numbering configuration | Read |
klara_prepare_invoice | Create an invoice with recipient and line items, or edit a draft | Code |
klara_prepare_send_invoice | Deliver a booked invoice: smart delivery or a fixed channel (email, ePost, eBill, print) | Code |
klara_prepare_next_number | Pull the next order or document number (advances the counter irreversibly) | Code |
Accounting
| Tool | Purpose | Access |
|---|---|---|
klara_bank_open_positions | Open positions of the bank reconciliation | Read |
klara_vat_report | Read the VAT report of a period (without recalculation) | Read |
klara_prepare_booking | Record a manual booking, optionally with a receipt PDF; debit/credit is checked upfront | Code |
klara_prepare_receipt_attachment | Attach a receipt PDF to an existing booking | Code |
Payroll
| Tool | Purpose | Access |
|---|---|---|
klara_search_employees | Employee directory with search, filter and sorting | Read |
klara_addable_salary_items | Which salary types may be added to a person's open payslip | Read |
klara_payroll_export | Generate the payroll interface file (content only on explicit request) | Read |
klara_prepare_salary_item | Record a variable salary item (hours, allowances, bonuses) on an open payslip | Code |
Company and confirmation gate
| Tool | Purpose | Access |
|---|---|---|
klara_prepare_profile | Update or create your own company's master data | Code |
klara_prepare_subscription | Create a KLARA subscription (paid, own contractual terms) | Code |
klara_pending_actions | Show prepared actions that are not yet confirmed | Read |
klara_confirm | Execute a prepared action with the confirmation code | Code |
klara_cancel_pending | Discard a prepared action | Write |
Security & data
- Login via OAuth 2.0, exclusively with an API key. The AI assistant never receives your KLARA API key – it stays encrypted on the KLARA MCP server (operated by ePost Service Ltd, hosted in Frankfurt) and is used only for calls to KLARA. There is deliberately no login with KLARA username and password: your password belongs only on KLARA's own login page.
- Your role determines access. KLARA MCP reaches exactly the areas that your API key's role opens in KLARA – nothing more.
- Data minimisation. Social security numbers, birth dates and personnel numbers never leave the server. Email addresses are masked in lists. Payroll export files return only format and size by default, not the content.
- What the AI assistant sees. Tool results – such as found customers or an invoice summary – flow into your conversation and are processed by the respective provider (e.g. Anthropic or OpenAI) like the rest of your chat content.
- Voluntary add-on service. The AI connector is not part of normal KLARA usage – you activate it deliberately and decide yourself which AI service to connect KLARA to. The chosen provider processes the retrieved content under its own terms, possibly outside Switzerland. The login page points this out when you connect.
- Deletion periods. Login links and one-time codes are deleted when they expire. Receipt content of prepared actions is removed immediately after execution, cancellation or expiry, their summaries after 30 days. Connections unused for 180 days are deleted together with the encrypted API key; the invoice log after one year.
- Privacy. Details on data processing at KLARA are set out in the privacy statement.
- Ending access. Delete the API key in KLARA under Users – access ends immediately and completely. You can additionally remove the connector in your AI assistant.
Troubleshooting
“Access denied” or an area is missing
Your API key's role lacks the permission, or your company lacks the matching KLARA subscription – without it, a function stays closed even for administrators. Ask the assistant for “KLARA whoami”: the answer shows which areas are open. For more access, create a key with the right role in KLARA under Users and reconnect.
A city is rejected when creating a record
KLARA validates cities against its own registry and knows some only with the canton suffix – for example “Studen BE” instead of “Studen”. Adjust the spelling and retry; the error message points this out.
Creating an invoice demands a document number
Your company numbers invoices manually. KLARA MCP then deliberately pulls no number from the counter – tell the assistant the next number in your series, and it is used as the document number. With automatic numbering this happens by itself.
No invoice PDF is created on booking
That's KLARA API behaviour: unlike the UI, it renders no document when booking. Ask the assistant to create the PDF afterwards – on request it attaches it to the booking.
New features don't show up
AI assistants memorise a server's tool list when connecting. After KLARA MCP updates, disconnect once and reconnect.
The first answer takes long
After a longer pause the server restarts (cold start). The first request can therefore take a few seconds; after that it's fast.
“This action is no longer valid”
Prepared actions expire after 30 minutes without confirmation – for safety. Simply ask the assistant to prepare the action again.
Server error with an incident id on booking, PDF or sending
Known issues in the KLARA interface (as of August 2026, reported to KLARA): booking invoices, rendering PDFs and sending can fail through the interface with a server error, while the same action works in the KLARA user interface. Perform the action in KLARA; the incident id from the message helps support.
Support
Questions, problems or security concerns about KLARA MCP: support@klara.ch
Helpful for a quick answer: the error message from your AI assistant – for KLARA errors it contains an incident id that makes the case unambiguous. Never include API keys or passwords.
More about KLARA: klara.ch · For developers: developer.klara.ch