Rob compares three popular Claude/agent skill packs: Addy Osmani's newly open-sourced set (25 skills plus four reviewer personas, built around a six-stage define/plan/build/verify/review/ship lifecycle), Matt Pocock's small composable skills focused on upfront alignment, and Lauren Tan's PStack focused on verification and evidence. His conclusion: Osmani's pack is the most team- and enterprise-friendly because it follows the conventional SDLC with no new metaphors to learn, Pocock's is best for fuzzy design problems, and PStack is best for gnarly bugs, migrations and long autonomous runs. The bigger argument is that you shouldn't install everything everywhere — ceremony should match the stakes, and extra skills bloat context and auto-trigger when you don't want them.
- Addy Osmani (ex-Google Chrome DX/web performance, now at Anthropic) open-sourced his agent skills and the repo hit roughly 100,000 stars, making it one of the most popular AI repos on GitHub.
- His pack is structured as a six-stage lifecycle — define, plan, build, verify, review, ship — each with a slash command, deliberately mapping to the standard software development lifecycle rather than inventing new vocabulary like Pocock's 'grilling'/'fog of war' or PStack's 'potato mode'/'arenas'.
- Notable commands include /build auto (approve the plan once, then every task runs autonomously but stays test-driven, self-committing, and halts on failure), /constraints (interviews you about your quality bar and writes constraints.md), /web-perf, and /code-simplify.
- Every skill contains an 'anti-rationalization table' listing the excuses an agent makes to skip steps ('this is too simple to test', 'I tested it manually') paired with the rebuttal.
- 'Doubt-driven development' spins up a fresh context whose only job is to doubt a non-trivial claim — adversarial review during the build rather than only at the end.
- The skills encode classic engineering principles: Hyrum's law for API design, the Beyoncé rule for testing, Chesterton's fence for simplification, trunk-based development, small atomic commits.
- Positioning: Pocock asks 'do we agree on what we're building', PStack asks 'can you prove it works' (no planning skills; 'the best spec is the code'), Osmani asks 'did we follow the process' — and he's the only one covering CI/CD, observability and deprecation, installable into ~70 agents.
- Rob's practical advice: prune your agents.md and skill files because models are already strong, match effort to stakes (just change the button vs. full security review for irreversible production work), and treat these packs like textbooks to steal from rather than religions to adopt wholesale.
The single most transferable idea in the pack — pre-writing an agent's excuses alongside rebuttals — and it's trivially copyable into anyone's own skills.
Every skill has what Addy would call an anti-rationalization table. It's a list of the excuses an agent will make to skip past a step... 'this is too simple to test' or 'I tested it manually.' If you've worked with agents or you've worked with juniors, you've heard all of these excuses before.
This is the video's actual thesis — a concrete tiered model for when to use heavy process versus just shipping, backed by Osmani's own gradual-rollout advice.
If you're just changing a button color, you don't need a PRD, a task breakdown, a five-axis arena review from PStack, or a security auditor. You just need to change the button and look at it.
Honestly, if you never install this, just reading through the skills is a better software engineering course than most.
It's not that they're actually borrowing from each other, it's just that software engineers converge on how to build software.
More skills doesn't necessarily mean a smarter agent.
Don't treat any of these packs as a religion. Treat them like an O'Reilly textbook — steal what works and build your own skills on top.