How We Unlock Millions in Productivity Gains Using Prompt Engineering for One of the Largest Banks in Belgium?

A GenAI success story with one of Belgium’s largest banks
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Prompt engineering may sound like a technical buzzword—but at Sailpeak, it has become a powerful lever for real business impact.

In a recent collaboration with one of Belgium’s largest retail banks, we delivered a tailored prompt engineering programme that unlocked millions of euros in productivity gains. From automating customer feedback analysis to streamlining internal workflows, the transformation didn’t require complex tech stacks or months of development.

It began with a simple shift: asking the right questions to AI.
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From Hype to Impact: Making AI Work for Business
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Artificial Intelligence is no longer a distant innovation. It’s already embedded in how organisations think, plan, and operate. But the reality is that many companies still struggle to extract meaningful outcomes from GenAI tools.

The reason? Not the model itself—but how it’s being used.

Prompt engineering is the art of providing AI with clear, structured instructions. Rather than vague queries that lead to unreliable answers, it enables teams to achieve targeted, consistent, and valuable results—across departments and use cases.

As our Prompt Engineer Léonard puts it:
“Most teams already have access to AI. The missing link is knowing how to talk to it.”

The Sailpeak Approach: A Framework for Precision Prompting

To turn this into a scalable practice, we developed a practical framework that helps teams structure their prompts around five core elements:

• Role – Define the role you want the AI to assume (e.g. analyst, recruiter)
  
  
• Context – Provide the background information or setting
  
  
• Task – Clarify the main objective
  
  
• Instruction – Add any specific formatting, constraints, or tone requirements
  
  
• Output – State the desired format or structure of the response
  
  

This framework became the foundation for dozens of prompt templates used across departments—from marketing and compliance to customer experience and HR.

For instance, rather than asking:

‍“Summarise this document,”
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a more effective prompt would be:
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“Act as a senior business analyst. The following document outlines our Q3 sales performance. Summarise the top three trends and key challenges, in one paragraph and a bullet list.”

A Measurable Win: 80% Automation in Customer Feedback Analysis

One of the most impactful use cases was in processing customer feedback.

Previously, analysts spent over two weeks categorising and summarising customer reviews manually. Using structured prompting, we developed a GenAI-powered workflow that:

• Automated 80% of the categorisation process
  
  
• Produced executive-ready summaries with key insights
  
  
• Reduced turnaround time from 10+ days to under 48 hours
  
  

This single workflow resulted in hundreds of hours of time saved annually—and enabled rapid access to valuable customer insights.

Scaling Prompt Engineering Across the Bank

As confidence in prompt engineering grew, so did the number of use cases. Employees across departments began using GenAI for:

• Drafting internal policy updates
  
  
• Analysing competitor websites
  
  
• Summarising regulatory documents
  
  
• Generating customer personas
  
  
• Prototyping communications copy
  
  

Prompt templates empowered non-technical teams to use AI tools independently. The result? Faster iteration cycles, reduced reliance on tech teams, and a more AI-literate workforce throughout the organisation.

Advanced Techniques: Refining for Accuracy and Confidence

To further enhance outcomes, we trained teams in key refinement strategies:

• Iterative Prompting – Experimenting with wording and structure to improve accuracy
  
  
• Requesting Rationale – Asking AI to explain its reasoning to identify hidden gaps
  
  
• Confidence Scoring – Having AI rate its certainty in outputs to guide review priorities
  
  

These techniques improved output reliability and fostered a culture of experimentation and ownership around AI use.

Why It Works: Fast ROI, Minimal Friction

Unlike large-scale AI transformations, prompt engineering delivers rapid, measurable returns with minimal resource investment:

• No new infrastructure
  
  
• No advanced development
  
  
• No lengthy onboarding
  
  

Just focused communication, applied at scale.

What our clients gained:

• Time savings across workflows
  
  
• Faster decision-making
  
  
• Improved output quality
  
  
• Broader internal AI adoption
  
  

What’s Next: Prompt Engineering as a Core Business Skill

We believe prompt engineering is becoming as essential as spreadsheet fluency or presentation design. As AI tools become embedded in daily work, the ability to communicate clearly with them will define who captures the most value.

At Sailpeak, we’re now helping more teams achieve similar gains through bespoke GenAI enablement programmes, mini applications, and prompt libraries.

Because when you learn to ask better questions, the answers start working for you.