~$ 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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This Week in Extensibility: the Chrome Web Store bans two extension categories, Mozilla proposes a permission model for AI agents, Cloudflare runs customer code before signup
Week of July 10–17, 2026: the Chrome Web Store bans prediction-market and AI-guardrail-circumvention extensions and narrows what any extension may collect, Mozilla proposes a...
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This Week in Extensibility: MCP's spec locks down its auth and skills, WebMCP gets conformance tests, WebAssembly components bind to real-world interfaces
Week of July 3–10, 2026: MCP's next spec locks down its client-auth and skill-distribution pieces before a July 28 launch, WebMCP gains a cross-vendor conformance suite, the...
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Loop Engineering: always be compounding
Loop engineering for AI agents should raise the floor on each iteration by creating tools and correcting instructions.