Terms of Service Language Ontology

Authors:
Elena Molino Peña
José María Cruz
José María García
Antonio Ruiz Cortés
Feedback:
GitHub isa-group/tosl (pull requests, new issue, open issues)
Download Serialization
License
CC-BY 4.0

Copyright © 2025 ISA-GROUP & SCORE-LAB

Abstract

This document presents an ontology designed to represent the contractual terms of Software as a Service (SaaS) Terms of Service (ToS) using the Open Digital Rights Language (ODRL). The ontology supports the formal representation of deontic modalities, enabling the precise definition of terms related to arbitration, applicable law, content removal, liability and modification/termination clauses. By leveraging ODRL, it ensures structured semantics for clear and precise interpretations of contractual obligations, permissions and prohibitions within SaaS agreements.

1. Introduction

Abusive services are characterised by the inclusion of unfair terms in their Customer Agreements (CAs), resulting in a substantial imbalance between the rights and obligations of the contracting parties, to the detriment of consumers. Legal frameworks such as the EU Directive on Unfair Contract Terms (UCTD) seek to protect consumers from the adverse effects of unilaterally drafted contracts imposed by service providers. However, identifying unfair terms remains a challenging task, requiring meticulous legalese analysis. This process is often tedious, time-consuming, and error-prone, resulting in a lack of awareness among consumers about the potential risks associated with accepting a service provider’s terms of service.

The ODLR Profile for Terms of Service Language (TOSL) aims to address the complexities of CAs by providing a formal mechanism for structuring and organising the set of responsibilities described in the ToS, in order to ultimately perform analysis operations on the structured knowledge. Specifically, TOSL extends the ODRL by incorporating the representation of liabilities, their limitations, and dispute resolution mechanisms, concepts that are difficult to represent using the existing ODRL framework. Additionally, it introduces new terms in the base vocabulary, as well as relationships and entities specific to this domain to represent the terms more accurately. The expanded terminology supports responses to the defined CQs, which partially ensures transparency and fairness, contributing to the creation of more equitable and understandable ToS, and mitigating operational risks.

Core Competency Questions
Competency Questions Domain Concepts
A. Is arbitration mandatory before taking any court action? Arbitration, Litigation, Dispute
LAW. Is the governing law fixed and different from the consumer's country of residence? Law, Consumer Country
CR. Can the service provider remove the consumer's content? Remove, Consumer Content
USE. Is the user legally bound by terms just by using the service? Consent, Implicit, Explicit
J. Does the jurisdiction require dispute resolution outside the consumer's residence? Jurisdiction, Consumer Courts, Dispute Resolution
LTD. Does the contract attempt to exempt the provider from liability for gross negligence or intentional damage? Liability, Any Damages, Limit
CH. Is the provider allowed to modify the contract unilaterally? Change, Prior Notice, Justification
TER. Can the provider terminate the contract unilaterally? Terminate, Justification

1.1 Profile diagram

The figure below illustrates the concepts defined by the ODRL Profile for Terms of Service. These concepts facilitate the modeling of statements outlined in cloud provider agreements and enable the evaluation of the previously formulated questions to identify potentially abusive contractual terms.

tosl concepts

1.2 Namespaces

Prefix Namespace Description
owl http://www.w3.org/2002/07/owl# [owl2-overview]
rdf http://www.w3.org/1999/02/22-rdf-syntax-ns# [rdf-concepts]
xsd http://www.w3.org/2001/XMLSchema# xmlschema
rdfs http://www.w3.org/2000/01/rdf-schema# [rdf-schema]
odrl http://www.w3.org/ns/odrl/2/ [ODRL Vocabulary]
skos http://www.w3.org/2004/02/skos/core# [skos-reference]
dcterms http://purl.org/dc/terms/ [dcterms]
vann http://purl.org/vocab/vann/ [vann]
profile http://www.w3.org/ns/dx/prof/ profile
tosl https://w3id.org/tosl/ ToS Language Profile

2. Profile specification

The TOSL profile focuses on specifying Terms of Service (ToS) terms by representing obligations, rights, prohibitions, limits of responsibilities for the parties, and conflict resolution aspects, enabling operations such as identifying potentially unfair terms. New objects that have been added, as well as extensions to the core ODRL vocabulary, are defined below.

2.1 Dispute Resolution

Label

Dispute Resolution

Definition

Employed to specify the mechanisms for resolving disputes among the parties involved in the agreement

Term

tosl:DisputeResolution

Sub-classes

tosl:Arbitration, tosl:Litigation

Property

tosl:takesPlaceIn, tosl:governedBy, tosl:tosl:condition, tosl:targetParty

2.1.1 Governed By

Label

Governed By

Definition

Establishes the connection to the specific legal framework that governs the agreement

Term

tosl:governedBy

Domain

tosl:DisputeResolution

Range

tosl:Law

2.1.2 Takes Place In

Label

Takes Place In

Definition

This term describes the relationship between Dispute Resolution and Jurisdiction, specifying the location where disputes are to be resolved

Term

tosl:takesPlaceIn

Domain

tosl:DisputeResolution

Range

tosl:Jurisdiction

2.1.3 On Dispute

Label

On Dispute

Definition

Represents the relationship between a Policy and its associated Dispute Resolution mechanism, specifying how, where, and under which law disputes arising under the Policy will be resolved

Property

tosl:onDispute

Domain

odrl:Policy

Range

tosl:DisputeResolution

2.1.4 Has Condition

Label

Has Condition

Definition

This relationship enables the specification of particular restrictions that apply to the dispute

Term

tosl:condition

Domain

tosl:DisputeResolution

Range

odrl:Constraint

2.1.5 Target Party

Label

Target Party

Definition

Specifies the type of party to which the liability or dispute resolution provision is intended to apply.

Term

tosl:targetParty

Domain

tosl:Liability, tosl:DisputeResolution

Range

odrl:Party

2.2 Arbitration

Label

Arbitration

Definition

Arbitration is a process for resolving disputes without recourse to conventional judicial systems, typically managed by an arbitrator

Term

tosl:Arbitration

Property

tosl:requires

2.3 Litigation

Label

Litigation

Definition

Litigation is a legal process in which the provider or customer, acting as the plaintiff, initiates proceedings against the other party, called the defendant, before a civil court in a settlement dispute

Term

tosl:Litigation

Property

tosl:requires

2.3.1 Requires

Label

Requires

Definition

This relationship specifies that all disputes must be resolved through arbitration

Term

tosl:requires

Domain

tosl:Litigation

Range

tosl:Arbitration

2.4 Jurisdiction

Label

Jurisdiction

Definition

Jurisdiction refers to the specific location or legal authority where a dispute must be resolved

Term

tosl:Jurisdiction

Property

tosl:takesPlaceIn

2.4.1 Consumer Place Courts

Label

Consumer Place Courts

Definition

Represents the jurisdiction corresponding to the place of residence of the consumer, typically used in B2C contexts for dispute resolution.

Term

tosl:consumerPlaceCourts

2.5 Law

Label

Law

Definition

Law refers to the specific statutes and regulations that govern an agreement and are applicable in resolving any disputes arising from it

Term

tosl:Law

Property

tosl:governedBy

2.5.1 Consumer Place Law

Label

Consumer Place Law

Definition

This provision states that the law governing the agreement is that of the consumer's country or the law that affects the consumer

Term

tosl:consumerPlaceLaw

2.5.2 California Law

Label

California Law

Definition

This instance denotes that the governing law applicable to the agreement is that of California

Term

tosl:californiaLaw

2.5.3 European Law

Label

European Law

Definition

this stipulates that the law regulating the agreement is European law

Term

tosl:europeanLaw

2.6 Liability

Label

Liability

Definition

Liability refers to the specific provisions that define and restrict the extent to which each party in the agreement can be held accountable for damages or losses

Term

tosl:Liability

Property

tosl:limitationOfLiability, tosl:liability, tosl:liableParty, tosl:targetParty, tosl:limitation

2.6.1 With Liability

Label

With Liability

Definition

Establishes the relationship between a rule, policy or asset and the applicable liabilities, describing the duties or obligations to be assumed in a specific context

Term

tosl:liability

Domain

odrl:Policy, odrl:Rule, odrl:Asset

Range

tosl:Liability

2.6.2 Liable Party

Label

Liable Party

Definition

This term establishes the connection between liability and a party to whom they apply

Term

tosl:liableParty

Domain

tosl:Liability

Range

odrl:Party

2.6.3 Target Party

Label

Target Party

Definition

Specifies the type of party to which the liability or dispute resolution provision is intended to apply.

Term

tosl:targetParty

Domain

tosl:Liability, tosl:DisputeResolution

Range

odrl:Party

2.6.4 Has Limitation

Label

Has Limitation

Definition

Defines a relationship that allows specifying particular restrictions or conditions related to the limitation of liabilities of a party

Term

tosl:limitation

Domain

tosl:Liability

Range

odrl:Constraint

2.6.5 With Limitation Of Liability

Label

With Limitation Of Liability

Definition

Defines the relationship that links a rule, policy or asset to the limitations of liability applicable to one or more parties, specifying the scope and restrictions in cases of damages or breaches

Term

tosl:limitationOfLiability

Domain

odrl:Policy, odrl:Rule, odrl:Asset

Range

tosl:Liability

2.6.6 Any Liability

Label

Any Liability

Definition

This liability provision specifies that the designated party may or may not be held liable for damages caused by the other party.

Term

tosl:anyLiability

Class

tosl:Liability

2.6.7 Physical Injuries

Label

Physical Injuries

Definition

This provision outlines the liability of the party in cases of physical damages caused to the other party

Term

tosl:physicalInjuries

Class

tosl:Liability

2.6.8 Harm Caused By Malware

Label

Harm Caused By Malware

Definition

The party is or not is responsible for any damages resulting from malware

Term

tosl:harmCausedByMalware

Class

tosl:Liability

2.6.9 Discontinuity

Label

Discontinuity

Definition

The party is not liable for any technical problems, failure, inability to use the services, suspension, disruption, modification, or discontinuance.

Term

tosl:discontinuity

Class

tosl:Liability

2.6.10 Any Indirect Damage

Label

Any Indirect Damage

Definition

The party is not liable for any special, indirect, punitive, incidental, or consequential damages.

Term

tosl:anyIndirectDamage

Class

tosl:Liability

2.6.11 Direct Damage

Label

Direct Damage

Definition

The party is liable for any direct damages.

Term

tosl:directDamage

Class

tosl:Liability

2.6.12 Any Loss

Label

Any Loss

Definition

The party is not liable for any disclosure, damage, destruction, corruption, failure to store, or loss of data and material.

Term

tosl:anyLoss

Class

tosl:Liability

2.6.13 Third Party Responsibility

Label

Third Party Responsibility

Definition

The party is not liable for any action, errors, omissions, representations, warranties, breaches, or negligence owed to third parties.

Term

tosl:thirdparty

Class

tosl:Liability

2.6.14 Service Content Liability

Label

Service Content Liability

Definition

The party is not liable for any information stored or processed within the services, or for inaccuracies or errors of information, or for content and material posted, software, products, and services on the website.

Term

tosl:serviceContent

Class

tosl:Liability

2.6.15 Breach of Contract

Label

Breach of Contract

Definition

The party is not liable for any failure to perform the contract or fulfill terms and obligations, including unavailability or failure to deliver products and services, or breach of agreement or lack of performance.

Term

tosl:breachOfContract

Class

tosl:Liability

2.7 Duty

2.7.1 Trigger

Label

Trigger

Definition

Represents the relationship where a permission can trigger a specific duty for a party

Term

tosl:trigger

Domain

odrl:Permission

Range

odrl:Duty

2.8 Action

2.8.1 Procedure

Label

Procedural Action

Definition

A procedural or administrative action not directly tied to the functional use or transfer of an asset.

Term

tosl:procedure

Class

odrl:Action

2.8.2 Remove

Label

Remove

Definition

This action may authorize, obligate, or prohibit the deletion of content from the provided services

Term

tosl:remove

Included In

odrl:use

Class

odrl:Action

2.8.4 Allow Download

Label

Allow Download

Definition

Allow download refers to the action that permits one of the parties, typically the client, to download personal information or information about contracted services

Term

tosl:allowDownload

Included In

odrl:use

Class

odrl:Action

2.8.5 Terminate

Label

Terminate

Definition

This action permits the termination of an asset, whether it be the agreement, services, or any other associated entity

Term

tosl:terminate

Included In

odrl:use

Class

odrl:Action

2.8.6 Publish

Label

Publish

Definition

This action mandates the public release of an asset

Term

tosl:publish

Included In

odrl:use

Class

odrl:Action

2.8.7 Integrate

Label

Integrate

Definition

This action allows, obligates, or prohibits the integration of the provided service with your application.

Term

tosl:integrate

Included In

odrl:use

Class

odrl:Action

2.8.8 Test

Label

Test

Definition

This action permits, mandates or prohibits the use of the services to test a software application.

Term

tosl:test

Included In

odrl:use

Class

odrl:Action

2.8.9 Develop

Label

Develop

Definition

This action permits, mandates or prohibits the use of the services to develop a software application.

Term

tosl:develop

Included In

odrl:use

Class

odrl:Action

2.8.10 Claim

Label

Claim

Definition

To submit a formal request or complaint regarding a perceived infringement or violation, typically related to legal or policy matters.

Term

tosl:claim

Included In

tosl:procedure

Class

odrl:Action

2.8.11 Appeal

Label

Appeal

Definition

The user may submit a formal appeal to contest the suspension or termination of their account.

Term

tosl:appeal

Included In

tosl:procedure

Class

odrl:Action

2.8.12 Assign

Label

Assign

Definition

To assign or transfer rights and/or obligations under an agreement to another party, such as an affiliate, subsidiary, or successor.

Term

tosl:assign

Included In

odrl:transfer

Class

odrl:Action

2.9 Asset

2.9.1 Service

Label

Service

Definition

An asset that includes the service affected by the action as a resource

Term

tosl:Service

Parent class

odrl:Asset

2.9.2 User Content

Label

User Content

Definition

An asset that encompasses either all or part of a user's content

Term

tosl:UserContent

Parent class

odrl:Asset

2.10 Left Operand

2.10.1 Justification

Label

Justification

Definition

This condition mandates that specific actions can only be undertaken with appropriate justification

Term

tosl:justification

Class

odrl:LeftOperand

2.10.2 Total Amount

Label

Total Amount

Definition

This stipulates the amount derived from a previous metric or calculation, which is used to compare against a specified threshold, such as a maximum or minimum allowable amount, in the context of a constraint.

Term

tosl:totalAmount

Class

odrl:LeftOperand

2.10.3 Inactivity Period

Label

Inactivity Period

Definition

This stipulates the duration of time a service may remain inactive or unused, serving as a parameter for triggering specific actions or evaluating compliance with constraints.

Term

tosl:inactivityPeriod

Class

odrl:LeftOperand

2.10.4 Consumer Resident Country

Label

Consumer Resident Country

Definition

This stipulates the country of residence of the consumer, used to compare against a list of countries in the context of constraints or conditions.

Term

tosl:consumerResidentCountry

Class

odrl:LeftOperand

2.10.6 Compliance

Label

Compliance

Definition

This left operand refers to the adherence to an specific rule or policy. I can be used to refine the semantics of an action that has to be performed in accordance to another policy. Permited values are and IRI, a odrl:Policy or an xsd:string

Term

tosl:compliance

Class

odrl:LeftOperand

2.10.7 Licensing Type

Label

Licensing Type

Definition

This stipulates the type of license or permission required by a party to perform a specific action or activity, such as a written permission.

Term

tosl:licensingType

Class

odrl:LeftOperand

2.10.8 Effect

Label

Effect

Definition

This stipulates the effect or impact that an action may or must not cause, serving as a parameter to evaluate the outcomes of an action.

Term

tosl:effect

Class

odrl:LeftOperand

2.11 Right Operand

2.11.3 Degradation

Label

Degradation

Definition

Indicates a significant and unreasonable degradation of some metric, such as response time or availability, caused by the action of the Rule to the target of the Rule

Term

tosl:degradation

Class

odrl:RightOperand

2.11.4 Written Permission

Label

Written Permission

Definition

A formal, documented authorisation required for a party to perform a specified action.

Term

tosl:writtenPermission

Class

odrl:RightOperand

2.11.5 Breach of Contract

Label

Breach of Contract

Definition

This term refers to a violation or non-fulfillment of the terms as stipulated within the Policy. With the left operand odrl:event or tosl:justification, it can be used in the constraint of a Rule that can only be exercised in case of such a breach.

Term

tosl:breachOfContract

Class

odrl:RightOperand

2.12 Party

2.12.1 Customer

Label

Customer

Definition

A party that uses the service, typically for non-commercial or general purposes.

Term

tosl:Customer

SubClass Of

odrl:Party

2.12.2 Business Customer

Label

Business Customer

Definition

A customer who uses the service as part of their business operations or commercial activities.

Term

tosl:BusinessCustomer

SubClass Of

tosl:Customer

2.12.3 Provider

Label

Provider

Definition

A party that offers, manages, or delivers the service.

Term

tosl:Provider

SubClass Of

odrl:Party

3. Examples

All the agreements modelled with TOSL are available in our GitHub repository. You can consult several sample agreements (e.g. Elsevier, OpenAI and partly GitHub), which exemplify the use of the full TOSL schema. Below are some examples using the new terminology added by TOSL.

3.1 Method of Dispute Resolution

3.2 Liability or Disclaimer of Liability of the Parties

A. References

[dcterms]
DCMI Metadata Terms. DCMI Usage Board. DCMI. 20 January 2020. DCMI Recommendation. URL: https://www.dublincore.org/specifications/dublin-core/dcmi-terms/
[ODRL Vocabulary]
ODRL Vocabulary & Expression 2.2 . Renato Iannella; Michael Steidl; Stuart Myles; Víctor Rodríguez-Doncel. W3C. 15 February 2018. W3C Recommendation. URL: https://www.w3.org/TR/odrl-vocab/
[owl2-overview]
OWL 2 Web Ontology Language Document Overview (Second Edition). W3C OWL Working Group. W3C. 11 December 2012. W3C Recommendation. URL: https://www.w3.org/TR/owl2-overview/
[rdf-concepts]
Resource Description Framework (RDF): Concepts and Abstract Syntax. Graham Klyne; Jeremy Carroll. W3C. 10 February 2004. W3C Recommendation. URL: https://www.w3.org/TR/rdf-concepts/
[rdf-schema]
RDF Schema 1.1. Dan Brickley; Ramanathan Guha. W3C. 25 February 2014. W3C Recommendation. URL: https://www.w3.org/TR/rdf-schema/
[skos-reference]
SKOS Simple Knowledge Organization System Reference. Alistair Miles; Sean Bechhofer. W3C. 18 August 2009. W3C Recommendation. URL: https://www.w3.org/TR/skos-reference/
[vann]
VANN: A vocabulary for annotating vocabulary descriptions. Ian Davis. Vocab.org. 7 June 2010. URL: http://purl.org/vocab/vann