The Swiss Code of Obligations (CO) has been the legal foundation for contracts in Switzerland for over a century. Today, AI tools - as used on platforms like CASUS - are changing how contract law is applied in practice. What the CO actually requires, where AI can help, and where human judgment remains indispensable are questions that matter equally to law firms and in-house legal teams.
The CO as the basis of Swiss contract law
The Code of Obligations governs the formation, content, and termination of contractual relationships in Switzerland. It applies as default law unless the parties agree otherwise. This means a large part of the CO can be modified or excluded by contract.
That has significant practical consequences. If a contract is silent on liability, termination, or warranty, the CO steps in as a fallback. This is not a weakness - it is a drafting tool. Leaving out a clause means accepting the statutory default.
This is one of the clearest areas where AI adds value in contract work: identifying gaps before they become problems.
Where AI fits into Swiss contract law practice
AI-assisted contract analysis is not a substitute for legal expertise. It is a tool that handles certain tasks faster and more systematically than a person working alone.
Identifying gaps and deviations
A common problem in contract work: a contract includes a liability clause but no liability cap. Or there is no provision for data protection responsibility. Finding these gaps manually takes time and requires good recall of standard requirements.
CASUS, a Swiss legal AI platform, addresses this with the Benchmark workflow. It checks a document against an internal playbook or established industry standards - for SPA, NDA, or DPA contracts, for example. The system shows which clauses are missing, incomplete, or deviating from the standard, and provides a concrete suggestion for each finding, including the option to insert a suitable clause directly at the right place in the Word document.
Structured risk prioritisation
A contract with twenty findings is hard to work through without a clear sense of what to address first. The CASUS Risk & Quality Review assigns each finding to a party and prioritises by severity: low, medium, or high. This makes it possible to identify negotiation potential quickly and manage the work in a targeted way.
Checking consistency and language
Long contracts are prone to subtle errors: a term is capitalised inconsistently; a cross-reference points to a section that does not exist; a placeholder was overlooked. The CASUS Proofread function checks spelling, grammar, terminology consistency, and structural elements such as numbering, cross-references, and annexes - without altering the legal meaning of any clause.
The regulatory framework: AI and law in Switzerland
Switzerland currently has no specific AI legislation. On 12 February 2025, the Federal Council mandated the Federal Department of Justice and Police (FDJP) to prepare a consultation draft for AI regulation by the end of 2026. Planned areas of regulation include transparency, data protection, non-discrimination, and oversight.
Until then, the Data Protection Act (DSG/nDSG), general liability law, and professional duty-of-care obligations set the relevant framework for AI use in legal practice.
What this means in practice
For law firms and legal teams, the position is: AI tools are not prohibited today, but the duty of care toward clients remains with the human professional. Lawyers remain responsible for reviewing and approving contract drafts, regardless of which AI tools were used in the process.
Data-compliant AI solutions therefore carry real weight. CASUS hosts data exclusively in Switzerland and the EU, transfers no data to the US, and retains no user data after a session (Zero Data Retention). There is also no manual access by third parties (No Human Review).
AI-assisted legal research on CO questions
Beyond contract analysis, AI can also support legal research on CO-related questions. The CASUS Legal Research module provides access to over 660,000 cantonal and federal court decisions as well as statutory law. Relevant reasoning sections from decisions are displayed directly within answers - no need to navigate to the original source.
This enables structured first assessments on questions such as: How does case law treat limitation-of-liability clauses in general terms? What are the requirements for extraordinary termination under CO 337? The outputs are source-based and traceable, not generated internet answers without legal grounding.
These assessments can be used directly in further work - as a rationale for a clause, as an internal memo, or as the basis for changes via Agent Mode in the chat.
Key CO clauses and their relevance for AI analysis
Some clauses in Swiss contract law are especially important in negotiations and come up regularly in AI-assisted contract review:
Exclusion and limitation of liability (CO 100/101): CO 100 restricts contractual exclusion of liability for intentional acts and gross negligence. Clauses that violate this are void. AI can identify whether a liability clause respects these limits and flag missing caps.
Termination (CO 266 ff., CO 337): In ongoing contractual relationships, notice periods and grounds for extraordinary termination play a central role. Without clear provisions, the default CO rules apply - which may not serve either party's interests.
Warranty (CO 197 ff.): Sales contracts carry statutory warranty obligations that can be modified by contract. Missing or unclear warranty provisions in supply contracts are a classic risk flag.
Data protection and GDPR compliance: Particularly in contracts with an international dimension or in DPAs, alignment with the revised nDSG and GDPR matters. AI can check whether standard clauses are in place.
Limits of AI in contract law
AI tools are well suited to recognising structured patterns, comparing clauses, and checking consistency. For complex transactions with unusual contract structures, unclear party interests, or heavily negotiated individual terms, automation reaches its limits.
Without a clear playbook or defined minimum positions, AI becomes a marking tool that lists findings without being able to assess which of them are genuinely critical to the negotiation. Human judgment remains irreplaceable - especially when weighing legal risk against commercial pragmatism.
CASUS for everyday contract work under Swiss law
Legal teams working with Swiss contracts who want a structured approach to AI can use CASUS directly in Microsoft Word or via the web app. The platform supports the full document lifecycle: from risk analysis and standards comparison through to language review before sending.
CASUS can be tested free of charge at app.getcasus.com/signup. Further details on data protection and hosting are available at /security.
FAQ
What does the Swiss CO govern in contract law?
The Code of Obligations (CO) governs the formation, content, and termination of contractual obligations in Switzerland. It applies as default law, meaning parties can agree to deviating rules. Where a contract is silent, the statutory CO provision applies.
Can AI apply Swiss contract law independently?
AI tools can identify clauses, compare them against standards, and flag gaps. The legal assessment of whether a clause is appropriate in a given situation - and what negotiation strategy makes sense - remains the responsibility of qualified lawyers.
Is using AI in Swiss contract work legally permitted?
Switzerland has no specific AI law. Using AI in contract work is permitted, provided professional duty-of-care obligations are met. Lawyers continue to bear responsibility for the quality of their work product.
Which CO clauses are most relevant for AI analysis?
The clauses most commonly reviewed are liability provisions (CO 100/101), termination rules (CO 266 ff., 337), warranty provisions (CO 197 ff.), and data protection clauses. These are often incomplete or deviating from standard in practice.
How does contract analysis differ from contract management?
Contract analysis covers the substantive review of a document: risk assessment, clause identification, and recommendations. Contract management, by contrast, covers the administration of contracts over their lifecycle - deadlines, renewals, and filing.
How does CASUS protect data when using AI?
CASUS hosts data exclusively in Switzerland and the EU, transfers no data to the US, retains no user data after a session (Zero Data Retention), and allows no manual access by third parties (No Human Review).
What is the difference between a benchmark and a risk review in AI tools?
A benchmark checks whether a contract meets a defined standard - for example, whether all standard clauses are present and complete. A risk review analyses the specific risks and weaknesses of a particular document from the perspective of one contracting party.
Can AI help with research on CO questions?
Yes. CASUS offers a Legal Research mode with access to over 660,000 cantonal and federal court decisions as well as statutory texts. Results are source-based and directly usable within the chat - for example, as a rationale when adjusting a clause.
