How Sedes works, and how to use it.

You do this once per account. You need two things: your Sedes key, which starts with sedes_, and this address, in which you replace the dots with the rest of your key:

https://api.getsedes.com/mcp?key=sedes_…

ChatGPT

1. Check your plan. Custom connectors work with Plus, Pro, Business, Enterprise and Edu, not with free ChatGPT. On Business and Enterprise, an administrator first has to allow them in the workspace settings, under Permissions & roles.
2. Turn on developer mode. Click your name at the bottom left and choose Settings, Apps (sometimes Apps & Connectors), Advanced settings. Turn on Developer mode.
3. Create the connector. In Apps, choose Create. Enter: name Sedes, description “Dutch legislation, case law and reference checking”, and under MCP server URL the address above. Choose No authentication, tick that you trust the application and click Create. ChatGPT then shows the list of functions.
4. Turn Sedes on in a conversation. Open a new conversation, click +, then More and Developer mode, and choose Sedes. If ChatGPT asks whether it may use a function, allow it: every Sedes function only reads.
5. Save the instruction. Create a project for your legal work (Projects, New project) and put the text from Connect under Instructions. It then applies to every conversation in that project.

Claude

1. Check your plan. Custom connectors work with every plan. Free Claude lets you add one. On Team and Enterprise, the owner adds Sedes through Organization settings, Connectors, Add, Custom, Web. Each member then clicks Connect next to Sedes, and steps 2 and 3 fall away.
2. Open the connectors. Click your name at the bottom left and choose Settings, Connectors. In newer versions this sits under Customize. Choose + or Add custom connector.
3. Fill in the connector. Name Sedes, URL the address above. Leave the advanced OAuth settings empty and click Add.
4. Turn Sedes on in a conversation. Click + below the input field (or Search and tools), then Connectors, and turn on Sedes. If Claude asks permission for a function, choose Always allow.
5. Save the instruction. Create a project, open Project instructions and paste the text from Connect. The connector then also works in the desktop app and on your phone.

Working with Claude Code or your own software? Then the key goes in a header; see Connect. After setting up, test with the two questions under Check that it works.

Sedes is an MCP server. MCP (Model Context Protocol) is the open standard that lets ChatGPT, Claude and other AI apps use outside tools. Once set up, your AI sees fourteen Sedes functions, each with a description of what it does.

Ask “Is a non-compete clause in a fixed-term contract valid?” and the AI reads those descriptions and decides which functions it needs. A typical run:

1. get_legislation {"ref": "art. 7:653 BW"}

   The AI fetches the text of the article as it stands today, with the link to wetten.overheid.nl.

2. find_leading_cases {"target": "art. 7:653 BW", "limit": 5}

   The AI finds the rulings cited most often, and by the highest courts, for that article.

3. get_ruling {"ecli": "…", "part": "considerations"}

   The AI reads the considerations of the best-fitting ruling instead of relying on a summary.

4. verify_quote {"ref": "…", "quote": "…"}

   The AI checks that the sentence it wants to quote is in that ruling word for word.

5. format_citation {"ref": "…"}

   The AI puts the source in the format of the Leidraad voor juridische auteurs, the Dutch citation guide.

The AI then writes its answer with the sources Sedes returned. If your app shows the calls, you can expand them and see exactly what was requested and what came back.

Sedes calls no AI itself. Every function is a lookup in Sedes’s own database, updated every night from the official sources.

Source text, verbatim. Statutes, rulings and parliamentary papers come back as the official source publishes them, in the original Dutch. Sedes changes no words or punctuation.

A stable identifier and the official citation. Every source has an id you can use in a document: an ECLI for rulings, the BWB number and article for legislation, kst-36765-3 for parliamentary papers, stb-2026-188 for the Staatsblad, a CELEX number for EU law and CVDR728652 for local regulations. With it comes the link to the official publication.

A status per reference. When a text is checked, every reference gets one:

• Correct

  resolved Exactly one document. You get the identifier, the title and the official citation.

• Candidates

  ambiguous More than one document fits, for example “art. 162 BW” (which Book?) or a date on which the Supreme Court gave several judgments. You get every candidate with the reason. Sedes never chooses.

• Does not exist

  not_found Recognised as a reference, but no such document exists in the sources. An invented ECLI ends up here.

• Not a primary source

  unresolvable Recognised, but it points to a journal or publication outside the public sources, such as NJ 2020/123 or a JAR number. Search by ECLI instead.

A status per quotation. When a quotation is checked:

• Correct

  exact The passage is there word for word.

• Correct

  normalized_match Word for word, apart from white space and line breaks.

• Not verbatim

  partial Part of it matches. Sedes shows what it really says, so you can correct the quotation.

• Does not exist

  not_found The passage is not in this source. Often a paraphrase presented as a quotation.

Long texts in parts. One answer holds up to about 8,000 characters of source text. If a ruling is longer, the AI requests the next part. Ask for a specific part or numbered ground and you get what you need straight away.

You do not need to know the names of the functions. Ask in your own words; the AI picks the function. To make sure it goes through Sedes, start with “Use Sedes:”.

One example from start to finish. A tenant has severe mould in their home and wants a rent reduction. This is how you find the rulings that support the case, and the rulings the other side will cite. Ask the questions one after another in the same conversation; the AI builds on what it has already found.

1. From facts to legal terms

   My client has rented a home since 2019 with severe mould in the bedroom and bathroom. The landlord does nothing, despite three letters. Which articles and legal concepts apply to this case? Do not search for rulings yet.

   Dutch judges write “gebrek” (defect) and “huurprijsvermindering” (rent reduction), not “my house is damp”. With their terms and the articles (here art. 7:204, 7:206 and 7:207 BW) you find far more.

2. Start with the article

   What are the leading rulings on art. 7:207 BW? Give the ECLI, the court, the date and the summary for each.

   find_leading_cases ranks by how often, and by which courts, a ruling is cited. You start with the rulings others build on too.

3. Search on the facts

   Find rulings since 2020 on rent reduction for mould in a rented home. Also search with the Dutch words judges use, such as schimmel, vochtoverlast, vochtproblemen and gebrek. Run several queries and combine the results.

   search filters by court, area of law and date and returns up to 20 results at a time. A few short queries with different words find more than one long one. The rulings are in Dutch, so search in Dutch.

4. Compare the facts

   Read the facts and considerations of the five rulings that look most like our case. How long did the defect last, how serious was it, and how much rent reduction did the court award? Put it in a table, with the numbers of the grounds.

   A summary says what a ruling is about, not whether its facts resemble yours. Have the AI read the ruling itself.

5. Look at the other side too

   Find rulings in which the tenant got no or a smaller rent reduction, for example because the mould was caused by the tenant’s behaviour or because the landlord did not know of the defect in time. What was the reason each time?

   These are the rulings the other side will rely on. Better that you know them first.

6. Follow the references

   Which later rulings cite the most important ruling in the table, and in which passage? And which rulings does that ruling cite itself?

   get_citations works both ways. That is how you find the line in the case law, including rulings that do not contain your search terms.

7. Check where it stands

   Was any of the rulings in the table later changed on appeal or in cassation? Note it for each ruling.

   The search results already mark an overturned ruling. get_case_chain shows the whole procedural history.

Whether it is a writ of summons, defence, statement of case, notice of appeal, pleading notes or advice: the steps are always the same. For each step, a question you can copy and adapt.

1. Facts and reference date

   The employment contract was concluded on 1 March 2018 and terminated on 15 May 2021. For every statutory provision, use the text in force on those dates.

   Give the dates from the file. Sedes then returns the law as it stood then, with its period of validity, instead of the current text.

2. The legal framework

   Which articles apply to summary dismissal for theft? Retrieve the text of each article with Sedes.

   The AI finds the articles and retrieves the verbatim text. You decide which ones to use.

3. Case law that supports it

   What are the leading rulings on art. 7:678 BW concerning theft of small value? Read the relevant considerations of each ruling and summarise per ruling what the court decided, with the numbers of the grounds.

   Ask for the numbers of the grounds. Then you can check every point in the ruling yourself.

4. Does the ruling still stand?

   Check with get_case_chain, for every ruling I use, whether it was overturned on appeal or in cassation.

   A judgment overturned on appeal does not belong in your document as support.

5. Legislative history and EU law

   What did the legislator say about the reasonableness of a non-compete clause in art. 7:653 BW? Give the parliamentary papers with their citation.

   Useful for an interpretation that goes beyond the text, and for an interpretation in line with a directive.

6. Quoting and citing

   Check every quotation in this section with verify_quote and cite every source under the Leidraad.

   Let the AI quote only what verify_quote has confirmed as verbatim.

The biggest gain is in the last step: having the draft checked before it goes out. Paste your text into the conversation with this question:

Check this draft with Sedes. Use resolve_citation for every reference to a statute, ruling or parliamentary paper and verify_quote for every passage in quotation marks. Give a list per reference: correct, does not exist, not verbatim or ambiguous, with the official citation and, for an error, the correct text. Do not change anything in the draft yourself.

You get a verdict per reference, as in the example on the home page:

Correct Does not exist Not verbatim Candidates

Documents from the other side are checked the same way. Do the rulings they rely on hold up, and are the quotations really there?

Below are the references from the other side’s statement of defence. Check with Sedes whether each ruling exists, whether the date and court are right, whether the ruling was overturned on appeal or in cassation, and whether the quoted passages are in the source word for word.

• No legal advice. Sedes checks whether a source exists and what it says verbatim. Whether a ruling supports your position is for you to judge.
• No commentaries, handbooks or journals. Only the public primary sources: legislation, case law, legislative history, official publications, local regulations, EU law and disciplinary law.
• Only published rulings. Rechtspraak.nl publishes a share of all rulings. A ruling that is not there is not in Sedes either.
• An AI can still misread the source. Even with the right text, a model can read a consideration too broadly. Read the passages you rely on yourself; the citation is always given.
• Updated every night, not every minute. A ruling from this morning is in tomorrow. Local regulations and disciplinary law are updated weekly.

If your AI does not use the Sedes functions, you are back to answers from the model’s memory. So save this instruction in your project:

Only cite statutes, rulings and parliamentary papers that you retrieved or checked with Sedes (resolve_citation, verify_quote), and give the official citation for every source.