How do you actually choose between 400+ AI models when building RAG without losing your mind?

I’m sitting here looking at Latenode’s model catalog and feeling a bit paralyzed. There are so many options: OpenAI, Claude, Deepseek, smaller specialized models… and I need to pick at least two—one for retrieval and one for generation.

In theory, having options is great. In practice, I’m overthinking this. Should I use GPT-4 for everything? Should I use a cheaper model for retrieval and save the big one for generation? Does it matter that much?

I tried deploying a quick FAQ bot workflow and just… guessed. Went with Claude for retrieval and GPT-4 for generation. It worked, but I have no idea if that’s the right pairing or just lucky.

For people who’ve actually done this in Latenode, how did you approach the decision? Did you test multiple combinations? Is there even a logical way to narrow it down, or does it really just depend on your specific use case?

The trick is not overthinking it. Start with what you know.

For retrieval, you want a model that’s good at understanding semantic meaning in text. For generation, you want one that’s coherent and follows instructions. They don’t have to be the same model.

What I do: start with a mid-tier model for retrieval (Claude or GPT-3.5) and a stronger model for generation (GPT-4 or Claude 3 Opus). Test it. If performance is good and costs are acceptable, you’re done. If retrieval misses things, swap to a stronger retrieval model. If generation is repetitive or off-topic, upgrade the generation side.

Latenode makes this easy because you can swap models in your workflow without rebuilding anything. Test, measure, iterate.

Don’t get stuck in analysis paralysis. Real data beats theory every time. Deploy something reasonable, see what breaks, then optimize.

You’re right to think about this, but you’re overthinking it too.

I found that the retrieval model matters more than the generation model. Retrieval is about finding the right information; generation is about formatting it well. If your retrieval pulls garbage, no generation model fixes that. So I weight my spending toward retrieval quality.

What helped me: I set a budget for token costs, then picked models that fit that budget. For a FAQ bot, GPT-3.5 for retrieval and Claude Instant for generation works surprisingly well. For something more critical, I upgrade both.

The real insight is that you don’t need the fanciest models for everything. Different tasks have different requirements. Latenode’s advantage is that switching models is one click, so you can actually experiment and learn what works for your data.

Model selection is a sampling and testing problem, not an enumeration problem. Start with known-good pairs from the literature or vendor recommendations. Test them against your specific data. Measure retrieval precision and generation quality separately.

Once you have a baseline, systematically vary one dimension—try different retrieval models with your generation model fixed, or vice versa. This gives you empirical data on what matters for your use case.

Latenode’s strength here is that the testing loop is fast. You’re not rewriting infrastructure between tests—you’re just adjusting model IDs and re-running.

Start with strong retrieval + decent generation. Measure real performance on your data. Adjust models based on where it fails, not theory.

Retrieval quality > generation quality for RAG. Prioritize retrieval model. Test real data.

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