<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom"><title>Ju Lin's AI Weblog: Evals</title><subtitle>An independent research notebook on AI engineering, agents, models and the systems around them.</subtitle><id>https://julin.ai/atom/tags/evals/index.xml</id><link rel="self" type="application/atom+xml" href="https://julin.ai/atom/tags/evals/index.xml"/><link rel="alternate" type="text/html" href="https://julin.ai/tags/evals/"/><author><name>Ju Lin</name></author><updated>2026-08-22T00:00:00+12:00</updated><entry><title>AI Engineering SKill Map</title><id>https://julin.ai/2026/08/22/ai-engineering-skill-map/</id><link rel="alternate" type="text/html" href="https://julin.ai/2026/08/22/ai-engineering-skill-map/"/><published>2026-08-22T00:00:00+12:00</published><updated>2026-08-22T00:00:00+12:00</updated><category term="ai-engineering"/><category term="agents"/><category term="evals"/><content type="html">&lt;p&gt;Andrew Ng&amp;rsquo;s wrote an &lt;a href="https://x.com/AndrewYNg/status/2090840747738374568"&gt;AI Engineering Skills Map&lt;/a&gt;, which lists six things to learn: LLM foundations, grounding models with data, building agentic systems, evaluation-driven development, operating in production, and machine learning foundations.&lt;/p&gt;
&lt;p&gt;As he broke it down, I think the most important skill is learning how to build reliable systems from LLM&amp;rsquo;s uncertain behavior.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;You don’t know in advance what an LLM will output&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;This is the only only truth you need to take away in this post, if you can&amp;rsquo;t remember all.&lt;/p&gt;
&lt;p&gt;You can&amp;rsquo;t design AI software the way you design normal software — plan it, build it, ship it — because you can&amp;rsquo;t plan around an output you haven&amp;rsquo;t seen yet.&lt;/p&gt;
&lt;p&gt;The AI engineering stack is packed with jargons now: MCP, CLI tools, sandboxes, memory and context management, harness, loop, RAG, prompt, multi-agent, (sorry, I cannot name them all, too much). But the core of AI engineering is surprisingly simple:&lt;/p&gt;
&lt;p&gt;Build something, observe what it does, evaluate whether that&amp;rsquo;s good enough, change the weakest part, and repeat.&lt;/p&gt;</content></entry></feed>