Arnaud Pouppeville Architect’s Notebook

Claude Code

Turning Architecture Into a Prompt Pipeline

How to build a reproducible architecture pipeline with Claude Code slash commands, hard gates, and input chaining. Step-by-step anatomy of one command.

Software Architecture

Architecture Artifacts in Order: The Missing Handoff Between Discovery, Design, and Delivery

How to chain event storming, ADRs, C4, and arc42 into a repeatable pipeline where each artifact feeds the next. A practitioner walkthrough with diagrams.

SQL Server

Why Your SQL Server View Is Slow (And How an Inline TVF Fixes It)

SQL Server views can hide an expensive GROUP BY boundary. Here's the diagnosis and how an inline TVF brought a 3-minute query to 4 seconds.

AI Coding

My Agent Can Say No: Spec-Driven Agent Code Review with OpenSpec

How OpenSpec CLI enables spec-driven agent code review: your agent can decline suggestions that conflict with documented architecture conventions.

Coding Agents

The Blast Radius Problem: Running Your Coding Agent in YOLO Mode

Running your coding agent in bypass mode on your laptop is the mistake. A VM with Tailscale and default-deny egress is how you shrink the blast radius.

Machine Learning

Production ML Without a Data Science Team

How a martech company shipped production ML with no data science team. Silver layer, AutoML, delta inference, and matchback validation to prove it works.

Artificial Intelligence

Natural-Language Search Over Image Libraries: RAG Architecture

How to make thousands of images searchable in plain language without CLIP: RAG architecture using vision at ingest, hybrid search, and custom retrieval glue.

Kubernetes

KEDA Didn't Just Save Us Money. It Saved Our Jobs From Themselves.

How we stopped AKS PDF workers from OOM-crashing using KEDA scale to zero, a dedicated high-memory node pool, and a Postgres queue trigger.

Software Architecture

Solving AI Sprawl: Using Git Worktrees and ADRs to Govern Parallel Agents

How a five-phase AI-assisted SDLC pipeline (SpecKit, Git worktrees, /done, Claude Poll, /fix-pr) enforces architectural discipline at speed without the AI sprawl.

Software Engineering

Two Kinds of Human-in-the-Loop — And Why LangGraph Needs Both

Two kinds of HITL interrupts in LangGraph: information gaps (stuck, need data) vs authority gaps (stopped, need approval). Design for both; use interrupt(), never END as pause.

Software Engineering

Agentic AI Governance: It Fails at System Assumptions

Agentic AI governance for mission-critical software: a three-tier model, ADR boundaries, and why AI fails at system assumptions, not syntax.

Software Architecture

How C4 Model + DDD Fixed My Team's Architecture Diagrams

How C4 model and DDD fixed our architecture diagrams: shared vocabulary, diagrams as code, and the C3 trap. Practical workflow for agile teams.

Data Engineering

Medallion Architecture in Azure Databricks: The Practical Guide

A practical guide to Medallion Architecture in Azure Databricks — what Bronze, Silver, and Gold layers do, what they cost, and when skipping a layer makes sense.

Data Engineering

How Z-Order Cut My Databricks ETL Time in Half

Z-Order cut my Databricks ETL from 1m40s to 50s per tenant. Here's why partitioning failed and how Z-Order works like a clustered index for Delta Lake.