Why an addendum and not a new contract?
Most SaaS contracts were signed before the vendor added AI features. So the contract regulates nothing about data use for model training, liability for AI output, or the right to decline new AI features. Negotiating a whole new contract is rarely feasible — an addendum is. The natural moment is a renewal, expansion or price change: that's when you have room to negotiate.
Below are the six topics that belong in every AI addendum, each with a sample clause. The wording is a starting point for negotiation, not a ready-made legal product.
1. Data use and model training
The most important clause. Without an agreement, the vendor can use your data (prompts, documents, usage data) to train its models — putting your business information into a model that also serves your competitors.
2. Transparency and notice of new AI features
AI often arrives via a routine update ("shadow AI"). This clause forces the vendor to tell you before it's switched on.
3. Liability for AI output
Standard terms almost always exclude liability for AI output entirely. A full reversal is rarely achievable, but a reasonable middle ground is.
4. Sub-processors and third-party AI
Your vendor often sources its own AI from a third party (a model provider). Without an agreement, you don't know who is processing your data — and that can change without notice.
5. EU AI Act compliance
The regulation places obligations on the provider of the AI system, but you as a user must be able to demonstrate that your vendors comply. Put the burden of proof where it belongs.
6. Exit and data portability
AI features create new lock-in: prompts, configurations, trained variants and generated output. Settle upfront, in the addendum, what you take with you on exit.
How do you get the addendum signed?
- Take stock first — which vendors have added AI, and what does the contract currently say? You're negotiating blind without an overview.
- Prioritise by risk — start with vendors that process personal data or business-critical data.
- Pick the moment — a renewal, expansion or an announced price increase. That's when the vendor wants something from you.
- Be reasonable but specific — clause 1 (no training on your data) and clause 2 (advance notice) are acceptable to most vendors; start there.
Would you rather build AI requirements straight into the tender or selection instead of fixing things after the fact? See AI procurement. For ongoing monitoring of new AI features at your vendors — including a flag when an addendum is needed — there is VendorManager.nl.
Frequently asked questions
What is an AI addendum?
An addition to an existing (SaaS) contract that specifically governs AI functionality: data use, model training, transparency, liability, sub-processors, compliance with the AI Act, and exit. The rest of the existing contract remains unchanged.
Can I force an AI addendum onto a running contract?
Legally, that's usually not possible — it's a change that requires both parties' agreement. In practice it works at a renewal, expansion or price change, when you have room to negotiate. Large vendors increasingly have their own AI terms; scrutinise those critically rather than accepting them at face value.
Isn't a data processing agreement (DPA) enough?
No. A DPA governs personal data under the GDPR. An AI addendum also covers non-personal data (business data, prompts, output), model training, AI-specific transparency, and obligations under the AI Act. The two complement each other.
Which clause matters most?
The ban on training with your data (clause 1). That risk is irreversible: once data has been trained into a model, you can't get it back out.
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