Topic

LLMs

19 articles on LLMs, written from production systems rather than documentation.

3 min read

Chain of thought: what it buys and what it costs

Asking a model to reason step by step improves some tasks and slows every one of them. The trade is latency and tokens, paid on every single call.

AIPrompt EngineeringLLMsPerformance
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3 min read

Choosing a model for one feature, not for the company

Teams pick one model and route everything through it. Most systems have several jobs with different requirements, and one answer fits none of them well.

AILLMsPerformanceArchitecture
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3 min read

Start with the evaluations that need no judgement

A surprising share of what matters in an AI feature is mechanically checkable. Those checks are fast, free and boring, which is why teams skip past them.

AIEvaluationLLMsRAG
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3 min read

Few-shot examples, and the point where they stop helping

Examples are the fastest way to fix a format problem and a slow way to fix a reasoning one. Adding more has a ceiling that arrives earlier than expected.

AIPrompt EngineeringLLMsContext Engineering
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3 min read

Fine-tuning teaches form, retrieval supplies facts

Teams reach for fine-tuning to make a model know their data. It is much better at teaching behaviour, and facts have a cheaper home.

AIRAGLLMsSystem Design
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3 min read

Using a model as a judge, and when to trust the score

Grading output with another model scales in a way humans cannot. It also has biases of its own, and a judge nobody validated is just a number.

AIEvaluationLLMsObservability
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3 min read

Open weight or closed model: the decision is mostly not quality

The capability gap narrows every few months. What does not narrow is the difference in who controls deprecation, data residency and your cost curve.

AILLMsArchitectureSystem Design
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3 min read

Prompt caching is the cheapest win available, if you order for it

Caching the stable prefix of a prompt cuts cost and time to first token substantially. It only works if the stable part is genuinely first.

AILLMsPerformanceContext Engineering
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3 min read

Prompts need regression tests more than code does

A prompt is a load-bearing configuration string with no type checker behind it. Changing one line can break behaviour nobody remembers depending on.

AIEvaluationPrompt EngineeringLLMs
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4 min read

Streaming responses breaks your error handling

Once you have sent a 200 and started writing tokens, there is no status code left for the failure that happens halfway through the answer.

AILLMsArchitecturePerformance
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3 min read

Getting structured output you can actually parse

Asking politely for JSON works most of the time, and most of the time is a poor guarantee for something a parser sits behind in production.

AILLMsPrompt EngineeringArchitecture
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3 min read

Writing a system prompt that holds up under change

A system prompt is the one piece of a feature everybody edits and nobody owns. Structure decides whether it stays coherent or becomes sediment.

AIPrompt EngineeringLLMsArchitecture
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Have a system to build?

Whether it needs designing from scratch or rescuing from its own success, tell me what you’re building and I’ll tell you how I’d architect it.

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