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Cube5

Beyond Pass/Fail Testing: Redefining 'Done' for AI Systems

January 12, 2026GovernanceBy Cube5 Team

Abstract

The integration of artificial intelligence (AI) —particularly generative AI—has profoundly transformed the foundations of IT project management. While traditional approaches rely on deterministic systems with reproducible and predictable outcomes, AI introduces stochastic behavior through probabilistic models whose results may vary with each execution. As a simple example, consider that a request to summarize a document will never produce the same output. This shift requires new approaches, not only for software testing, but also for project acceptance, both technically and contractually.

This article explores the associated repercussions for both vendors and clients, highlighting the paradoxes linked to validating non-deterministic systems, and proposes concrete solutions to adapt testing and validation practices to the realities of AI.

Introduction

Before the rise of generative AI, IT systems were predominantly deterministic. A known input would yield a predictable output, and the success of a project largely depended on this ability to anticipate and reproduce behavior. The emergence of AI—particularly generative models—has complicated this model.

By nature, probabilistic AI – such as Large Language Models (LLMs) – operates through stochastic processes: it can produce different results from one execution to the next, even when given the same input. This inherent variability introduces a degree of uncertainty that is incompatible with traditional validation approaches. The shift from a deterministic paradigm to a probabilistic one challenges how projects are designed, tested, validated, and contractually framed.


Challenges

The core challenge of AI-integrated projects lies in the mismatch between traditional acceptance methodologies and the fundamental characteristics of AI systems. Historically, technical and functional testing has followed a deterministic logic: for each input, an expected output is defined, and validation is binary—either the test passes or it fails. This works well for conventional systems but becomes ineffective in the face of AI’s stochastic behavior.

Indeed, AI models—especially those used in generative contexts—can deliver varied outputs for the same input. This unpredictability makes it difficult to apply classical test plans, as the output cannot easily and consistently be compared with the expected results. The likelihood of diverging outputs is high, which undermines test validation, prolongs acceptance phases, and may lead to endless testing cycles. Furthermore, this variability complicates defect reporting, since a bug that appears once may not be reproduced, thus failing the usual criteria for defect recognition.

The change in expected output—from a precise, identical result to a plausible or satisfactory one—necessitates a rethinking of testing strategies. Validation is no longer about strict conformity to a predetermined result but about evaluating similarity, coherence, relevance, and business value. This tension between deterministic expectations and probabilistic realities defines the core challenge of AI project acceptance.


Trapped in the Acceptance Loop: The Hidden Risk of Deterministic Testing

One major risk scenario occurs when deterministic test plans are applied to systems that inherently produce variable outcomes. Even minor differences between the AI output and the expected output can cause test failures. These failures, in turn, lead to rework and re-testing, potentially trapping the project in an infinite acceptance loop.

The nature of generative systems makes this loop difficult to apprehend in the first place. Take, for example, a model tasked with generating a summary of a document. It will produce a different version each time, even though each version may be equally valid from a business perspective. Still, a traditional test that compares against a fixed expected result will reject these variations, no matter how relevant. The result is a project that cannot progress to acceptance, placing the vendor in a vulnerable position.

When Flaws Disappear: The Challenge of Non-Reproducible Defects

Another scenario arises when a sporadic issue is observed but cannot be reproduced. In conventional testing practices, a defect must be repeatable to be officially recognized.

However, in stochastic systems, such repeatability is not guaranteed. An unexpected or incoherent output may appear once and then vanish in subsequent tests. Since it does not recur, the testing team may refuse to log it as a defect, or worse, the development team may classified it as “Not a bug, Impossible to reproduce”. As a result, the issue is dismissed—even though it may degrade user experience or system reliability. This creates a paradox: a solution may pass all acceptance tests not because it’s flawless, but because its flaws are too random to validate.

Trapped by Determinism: The Vendor’s Dilemma

When acceptance criteria are based on deterministic tests, the vendor risks uncontrollable project overruns. An infinite loop of testing and correction—driven by unrealistic expectations—can lead to significant delays and cost overruns. In a fixed-price contract, this translates into financial losses; in a time-and-materials model, it impacts profitability and potentially harms the vendor’s reputation.

Vendors may find themselves investing time and resources in endless justifications or unnecessary rework, all due to an evaluation model that does not reflect how AI behaves. Worst case, the misalignment between contractual terms and technical reality may undermine the client relationship.

The Client’s Exposure

Clients also face considerable risks. In an endless acceptance scenario, delays can jeopardize business objectives and operational schedules. Depending on the contract type, financial consequences may follow—especially in T&M engagements where budgets can spiral.

Conversely, in the scenario where no defects can be officially reported, the client loses control over quality. The delivered system may contain undetected or unacknowledged issues, which affects reliability, adoption, and long-term trust in the solution.


Solutions: Redefining Success in AI Acceptance

To address these challenges, project acceptance must evolve in line with the probabilistic nature of AI systems. This means redefining what constitutes a “successful” test.

One effective approach is to introduce probability thresholds into validation criteria. Rather than requiring identical outputs across executions, acceptance can be based on a minimum percentage of satisfactory results. For example, a model might be considered valid if 85% of its responses are rated as relevant by domain experts.

Additionally, evaluation should be refocused on business value. Even if AI outputs vary in form, they can be deemed acceptable if they meet the intended operational goals. This requires active involvement from business stakeholders during the acceptance phase, as their judgment becomes central to the validation process.

However, relying solely on human reviewers is rarely scalable, especially as the complexity and volume of outputs grow. To address this, organizations can leverage large language models (LLMs) as automated judges in the acceptance process. Here, domain experts and business owners first define the intended outputs or outline clear criteria for what constitutes an acceptable response. These definitions serve as the reference standard. In subsequent testing runs, an LLM is prompted with these criteria and evaluates whether the AI system’s outputs meet the intended requirements. This approach allows for rapid, consistent, and scalable assessment across large datasets, reducing the bottleneck of manual review while maintaining alignment with business goals. When the LLM encounters ambiguous or borderline cases, these can be escalated for human review, ensuring that nuanced judgment is still applied where necessary.

Finally, teams must embrace non-reproducible anomalies as legitimate signals for improvement. Even if a bug occurs only once, it should trigger investigation and, where appropriate, model fine-tuning. Acceptance becomes less of a one-off milestone and more of a continuous, collaborative refinement process.


Four approaches for modernizing acceptance testing for AI

Empowering Teams for AI Acceptance

These shifts have concrete implications for project teams. Testers must adopt a new mindset—one that embraces qualitative assessment and understands probabilistic behavior. Test cycles may grow longer, if performed manually, due to the need for multiple executions and a more nuanced evaluation process.

Moreover, business users must be involved from the earliest phases of the project, as their judgment is key to validating system outputs. This transformation requires upskilling across all roles, along with dedicated onboarding and awareness sessions to explain the specificities and limitations of AI systems.


Cube5 solution and approaches

Across all these challenges, Cube5 provides a coherent and proven approach to embed acceptance within AI project delivery. Our methodology aligns probabilistic behavior with deterministic expectations through structured evaluation matrices, probabilistic thresholds, and business-oriented validation criteria.

1. Adaptive acceptance models and statistical validation methods are integrated directly into delivery, ensuring that variability is managed within transparent and measurable boundaries. By combining automated assessment through large language models with targeted human oversight, we ensure both scalability and reliability in validation.

2. Sporadic or non-reproducible anomalies are treated as opportunities for continuous improvement, turning uncertainty into actionable insight. 

3. In parallel, Cube5 fosters collaboration between technical and business teams through dedicated workshops, onboarding, and AI bootcamps that build a shared understanding of AI behavior, governance, and quality standards. In doing so, 

Cube5 transforms AI acceptance from a source of risk into a structured, business-aligned, and confidence-building process.


Conclusion

The acceptance of AI-based projects cannot follow the same standards as traditional IT systems. The stochastic nature of AI demands new tools, methods, and sometimes new contractual frameworks. As demonstrated in this article, the risks associated with project acceptance are not eliminated—they are simply redistributed. It is essential to anticipate these risks and redefine acceptance processes to align with the true behavior of AI systems.

Conversely, integrating AI itself into the acceptance process can significantly streamline the process, empowering humans to make the final decision of acceptance.

This calls for early stakeholder education, revised test methodologies, and a governance model that acknowledges uncertainty while maintaining control. Only by adapting acceptance practices to the realities of intelligent systems can organizations fully leverage the power of AI while preserving project rigor and delivery quality.