NotesByLex

A digital garden about AI, software, learning, and other assorted topics.

Hi, I'm Lex Toumbourou. I'm a machine learning engineer and software developer based in Brisbane, Australia, currently a Staff MLE at Canva. These are my working notes that I've been collecting over the last decade+ using the Zettelkasten method.

More about me

Essays

All essays
  1. Building an Agent Harness From Scratch

    Basically just while loops.

  2. Can Claude Opus 5.5 find any new leads on Satoshi Nakamoto?

    Let's see if Claude can find anything that the New York Times missed.

  3. Giving Up on Smart Rings

    The downsides to wearing a fitness-tracking device on your finger

  4. MCP is Now a Stateless Protocol

    A new MCP specification that removes handshakes and mandatory sessions.

  5. 6 Months of OpenClaw

    Macros, workouts and life admin.

  6. Completing A Computer Science Degree On Coursera

    A short write-up on my experience completing a Computer Science BSc from my bedroom.

  7. Shipping a Laptop to a Refugee Camp in Uganda

    The surprisingly difficult ordeal of sending a decade-old MacBook to a friend in a Ugandan refugee camp.

  8. AI-Induced Cognitive Atrophy

    We probably need to do deliberate daily mental exercise

  9. Naming Things Is Easy Now

    I guess there is only one hard thing left in Computer Science?

  10. Obsidian Markdown Notebook: code execution with outputs stored in the file

    A Jupyter Notebook-style Obsidian plugin that runs code in your notes and stores the outputs directly in the Markdown file.

Notes

All notes
  1. model Claude Haiku 5.5
  2. model GPT 6 Sol and Luna
  3. model Claude Opus 5.5
  4. paper An Empirical Study of Harness Design for Coding Agents
  5. model Qwen3.8-Max
  6. paper LLM Agents Do Not Reliably Follow Company Policies
  7. paper Decomposing LLM Judge Scores Into Yes/No Questions
  8. news OpenAI and Hugging Face security incident - July 21, 2026
  9. model Kimi K3
  10. paper Heavy Thinking: A Test-Time Scaling Pattern for Hard Problems
  11. paper LLMs Corrupt Your Documents When You Delegate
  12. note LLM Training Pipeline