IDEAS, DECISIONS & LESSONS

Journal

Notes on AI, architecture and building useful products.

878 articles

27 Aug 2026 · 4 min read

agent architecture

How xAI Builds Grok — and How I'd Build a Grok of My Own

Grok isn't a model, it's an agent system: tools trained into the reasoning, real-time X and web search on xAI's infra, a four-agent cross-verifying architecture, long-running agents. I break down its features, architecture, and safety harness — then map each piece to a component I can build self-hosted on a subscription I already pay for.

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26 Aug 2026 · 4 min read

agentic engineering

You Can't Ship Agents on Vibes — Evals for Agentic Systems

A one-line prompt tweak can silently break an agent, and you won't notice until a user does. My fix is an eval harness: a golden set of inputs and checks, run against every agent and workflow on every change. Here's the anatomy — deterministic checks, LLM-as-judge, run-on-change regression, and grading multi-agent workflows.

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