~$ Hello, world! I'm Todd — PhD computer scientist and co-founder/CEO of PixieBrix.
I write here about browser extensibility, engineering practice, and applied reasoning.
Browser extensions
Permissionless innovation and malleable software.
Engineering practice
Marrying process and tools to create value
Reasoning & rationality
Interplay between human knowledge and AI systems
AI Coding Summit 2026: Making AI coding work for enterprise-grade browser extensions
Watch the talk
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A brief history of browser extensibility
How the major browsers arrived at the extension models they ship today — and why those choices still shape what's possible.
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Effective debugging: the observe-hypothesize-test cycle
A methodical approach to non-trivial bugs, borrowed from how researchers actually work.
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ACH as Bayesian reasoning in disguise
The Analysis of Competing Hypotheses worksheet is naive Bayes with a friendlier UI. Pairs with an interactive explorer.
Latest: ACH as Bayesian reasoning in disguise —
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Beliefs hitchhike like genes
A new explorer that clusters public thinkers by the genome of their beliefs, inspired by genetic hitchhiking.
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agent-browser-shield is live on Product Hunt
agent-browser-shield, a source-available defense layer for AI agents in the browser, is on Product Hunt today.
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agent-browser-shield June 3 update: 14 new rules and the Chrome Web Store listing
14 new rules shipped in agent-browser-shield, now installable from the Chrome Web Store, and using it for daily driving.