What is an MCP server
Model Context Protocol (MCP) is an open standard through which an AI assistant calls external tools: it searches a register, opens an article of a law, reads a court decision. An MCP server is the program that gives the assistant these tools.
What MCP is
Anthropic created MCP and opened it as a standard. Claude, ChatGPT and other AI assistants now support it.
The standard has three parts. The client is the assistant you talk to. The server is the program that gives tools. A tool is one action with a description and parameters, for example "find the article of a law in its edition on a date".
You connect a server once. Then the assistant decides when to call a tool, and shows which calls it made.
ua_law__get_unit_in_force The tool gives the text of the article in force on that date, the date of the edition and a link to the act in the database of the Verkhovna Rada.
How an assistant calls a tool
1. You ask a question in plain words.
2. The assistant sees the list of the tools of the server with their descriptions and picks one.
3. It fills in the parameters: a case number, an ЄДРПОУ code, an article number, a date.
4. The server searches the source and gives the data with the date of the source (as_of).
5. The assistant answers from these data and names the source.
ua_court_hearings__search The tool gives the hearings from the schedule of the court: date, time, judge and room, with the date of the schedule.
Why a model makes mistakes without MCP
With no tools, a model answers from memory. Its knowledge ends on the date of its training, and the editions of laws and the case law change every week.
So a model can quote an edition that is no longer in force, or give a case number that does not exist. Such a text looks convincing, and you see the mistake only when you check.
With an MCP server, the model takes the article, the decision or the register entry from the primary source. The answer shows the source and its date, so a check takes seconds.
An empty result does not mean "there is none". It means that the query found nothing, and a good assistant says so.
ua_lpd__searchua_edrsr__search The tools give the legal positions of the Supreme Court and the decisions of the court register with case numbers that you can open and check.
Security and data
Read only. The tools of the Merit MCP server change nothing and send nothing in your name.
Sign-in, not a key. Claude and ChatGPT connect through a sign-in to the Merit account (OAuth). You do not copy a key.
You revoke each connection separately in the account. Then the server accepts no request of that connection.
A log with no content. For each call we record the connection key, the time, the tool name and the IP address. The log does not keep search words, case numbers or ЄДРПОУ codes.
The vendor of the assistant processes your conversations, not us. Do not send to the chat what your professional secrecy does not allow.
ua_edr_companies__lookupua_enforcement_proceedings__searcheu_sanctions__searchofac_sanctions__searchuk_sanctions__searchun_sanctions__search The tools read the company register (ЄДР), the enforcement system and the sanctions lists of the EU, the USA, the UK and the UN. Each list answers only for itself.
Which assistants support MCP
Claude: claude.ai, Claude Desktop, the mobile apps and Claude Code. How to connect: the Merit MCP server in Claude.
ChatGPT: custom MCP servers in ChatGPT Business and Enterprise workspaces. How to connect: the Merit MCP server in ChatGPT.
Other MCP clients connect with a key from the Merit account.
ua_legal_indicators__get The tool gives the rate on that date and the act that set it.
Questions
How is an MCP server different from an API?
An API is an interface for a programmer: to use it, you write code. An MCP server describes its tools so that the assistant itself knows when and how to call them. A lawyer does not need to program anything.
Does the MCP server see my conversations with the assistant?
No. The server gets only the tool call with its parameters, and gives back the data of the source. The vendor of the assistant sees the conversation.
Does it replace a lawyer?
No. An assistant with MCP finds primary sources faster, but the model makes the conclusion, and it can be wrong. Check each reference. A lawyer makes the decision in a case.
What does the Merit MCP server give?
The legislation of Ukraine with its editions on any date, case law, the company register, the registers of advocates and notaries, enforcement proceedings, debts, bankruptcy and sanctions lists, in one connection.
Ukrainian law and registers in your assistant
The Merit MCP server gives Claude and ChatGPT the legislation, the case law and the state registers of Ukraine. Each answer comes with its source and date.