Skip to content
Notifications
Clear all

ELI5: Why does it sometimes give a great answer and sometimes a terrible one to the same prompt?

3 Posts
3 Users
0 Reactions
0 Views
(@diego_h)
Reputable Member
Joined: 4 months ago
Posts: 152
Topic starter   [#22886]

I’ve been testing DeepSeek Chat for a small integration project, and I noticed something odd. Sometimes I ask it to explain how webhooks work with a REST API, and the answer is clear and actionable. Other times, I ask the exact same question later, and the answer feels generic or misses key details.

Why does this happen? Is it because of server load, some randomness in how it picks answers, or maybe it’s using different versions of the model behind the scenes? I’m trying to understand how reliable it is for API design tasks.


Still learning.


   
Quote
(@cloud_sec_enthusiast)
Estimable Member
Joined: 2 months ago
Posts: 119
 

Great question, and you're hitting on something I've seen with API services in general, not just LLMs. The inconsistency can be super frustrating when you're building something.

A big part of it is the built-in randomness (temperature setting) used to make answers feel less robotic. Sometimes that variation helps, other times it derails a technical explanation. Server-side changes are also a factor - they might be A/B testing a new model version or tuning parameters without notice, which can shift the output quality.

For API design work, I'd treat the first answer as a draft. If it's good, save it. If it's bad, refine your prompt slightly or ask for a more specific example. It's a bit like dealing with a flaky third-party service - you need a retry logic in your process 😅


security by default


   
ReplyQuote
(@carolinem)
Trusted Member
Joined: 2 weeks ago
Posts: 67
 

The temperature parameter is indeed part of it, but it's more nuanced than simple randomness. The model's output is a probability distribution over tokens, and temperature scales this logits space. A higher temperature increases the chance of sampling lower-probability tokens, which can lead to creative but less precise technical explanations. For a query like explaining webhooks, this can cause the model to sometimes follow a coherent, high-probability reasoning path and other times veer into a more generic, templated response pattern that exists in its training data.

You mentioned server load and different model versions, which are significant but often overlooked factors. Providers frequently run concurrent A/B tests on routing layers or model variants, documented in papers like "Serving Large Language Models" from Stanford. Your identical prompt could be served by a different model checkpoint or a different inference configuration, like a changed top-p value, without any user-facing indicator. This is a known challenge for reproducibility in LLM-assisted development.

For API design reliability, I'd suggest a systematic approach: log the exact prompt, timestamp, and a hash of the response. If you notice a quality drop, check if it correlates with time of day, which could indicate load-based degradation. Treat it as a non-deterministic system and implement a validation step, perhaps using a second, more focused prompt to critique the first answer's completeness on webhook specifics.


Nullius in verba


   
ReplyQuote