Making AI reliable: How structured prompts reduce randomness

Large language models (LLMs) inherently exhibit non-deterministic behavior, meaning the AI might produce different answers when asking it the same question. An LLM generates text by predicting the next most probable word in a sequence. This involves focusing on relevant parts of the input and accessing the models internal knowledge, which introduced randomness causing this non-determinism.

Although randomness is useful for creativity, it can cause issues in software engineering, where consistent outputs are essential.

When an LLM processes similar prompts, minor wording differences can trigger different internal thought processes. This creates a digital “butterfly effect,” causing inconsistent writing styles, varied interpretations of tasks, and different solutions.

For instance, two developers using AI might produce functions that differ slightly in coding style or details. While both could work, these differences create maintenance problems, fragmented knowledge, and a confusing codebase that’s hard to debug or evolve.

Our strategy is straightforward: use structured prompt templates to clearly define instructions and operations. These templates guide the AI through a controlled thought and action process, preventing ambiguous or inconsistent outputs. By clarifying expectations, AI consistently produces results aligned with standards.

Guiding AI through clear steps

A proven method to increase consistency is to guide the LLM through structured steps: analysis, planning, and execution, instead of immediately asking for a final answer. This approach breaks down tasks into smaller, logical steps helping the AI approach tasks methodically.

Analysis

In the first step, the AI analyzes the problem, identifying key issues and referencing existing resources. This helps the AI clearly understand what’s required and ensures crucial details aren’t missed.

Plan

Next, the AI creates a detailed action plan. This step acts like a blueprint, clearly laying out necessary tasks. By providing clear guidelines, the AI’s thought process aligns better with expectations.

Execute

Finally, the AI executes the plan, generating solutions based on the defined structure. Following a clear blueprint significantly reduces variation in the results, ensuring consistency with desired standards.

Consistent instructions lead to consistent solutions

Consistency is critical in software development. Without standard instructions, similar tasks could result in different solutions, complicating future work.

Structured prompts serve as guidelines, defining output formats, naming conventions, libraries, or design patterns. Consistent instructions ensure similar tasks produce similar solutions, maintaining coherence and ease of maintenance. These prompts can evolve but maintain standards over time.

Standardized prompt templates (like those used for implementing features from user stories) ensure the AI consistently produces the desired outcomes, avoiding confusion or conflict. You can also create new instruction templates to accommodate evolving development needs.

Using context to guide AI

Providing detailed context is critical for reliability. Without specific context, AI defaults to general information, leading to generic or incorrect outputs.

Context includes detailed information like data models, API contracts, architecture documents, user stories, and project requirements. This detailed information focuses the AI’s output within clear boundaries, avoiding irrelevant or inaccurate results.

Because an LLM’s knowledge is distributed, detailed prompts act as filters, guiding the AI toward relevant and valuable information.

For example, robust user stories and detailed API specifications guide the AI toward producing professional-level code, avoiding irrelevant or amateur-level responses. Clearly added context ensures the AI focuses on generating relevant, high-quality outputs.

Final thoughts

Reducing unpredictability in AI-assisted software development requires clear structure, discipline, and detailed context. By using structured prompt templates and a step-by-step approach, AI consistently addresses tasks with precision and relevance. Providing detailed context further ensures solutions meet specific project requirements, transforming AI into a reliable partner that consistently delivers high-quality, maintainable code.

If you’d like to read more of my in-depth thoughts on mitigating LLM non-determinism with structured templates, check out my article on LinkedIn.