The argument in one line.
Stop copying skill libraries from GitHub and build your own lightweight five-step loop—Research, Prototype, Plan, Build, Test—that compounds over time and actually fits your codebase.
Read if. Skip if.
- You're building with Claude/agentic systems and currently clone skill repos wholesale, wanting to compress multiple libraries into one portable mental model.
- A developer 6-18 months into agent-driven workflows who's hit friction scaling custom skill systems and needs a systematic collapse of common patterns.
- You ship incrementally in sprints and need a five-step loop you can hold in working memory without re-reading documentation between projects.
- You're still in your first 2-3 weeks with Claude and haven't yet built a custom skill yet — this assumes you know what a skill.md file is and why you'd want one.
- You work primarily in non-agentic workflows or use Claude only for one-off tasks, not repeated project harnesses.
The full version, fast.
Stop cloning every viral skill repo and build your own lightweight harness instead, because the best agentic system is the one you accumulate from your own code base over time. Across Gary Tan, Matt Pocock, Adi Asmani, BMAD, superpowers, and Everything Claude Code, the same five-step loop keeps surfacing: research the idea in ask mode, prototype a front-end-only wireframe with dummy data, plan in vertical slices using the agent's native plan mode, build incrementally, then test with a mix of automated checks and human smoke testing. Write skills only when the agent repeatedly fails, keep them to a few paragraphs, treat them as living documentation, and add a polish pass with a second model when stakes are high.
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01 · Cold open + promise
Surveyed all major skill libraries. Promise: distill to reusable patterns. Sponsor mention (CodeRabbit).

02 · What are skills again
Skills = SKILL.md files with front matter, always loaded into model context. Agent Harness diagram: Planning, State Mgmt, Memory, Tool Runtime, Skills, Evaluators, Reasoning Engine.

03 · Skill libraries are trending
Explosion of community skill repos. Everything Claude Code at 183K stars. Common denominators across all of them.

04 · Library 1 + 2: Addy Osmani + Matt Pocock
Osmani: spec to plan to build to test to review loop. Pocock: diagnose, grill-with-docs, TDD, prototype step.

05 · Test-Driven Development
All frameworks advocate some TDD. Caveat: agents can cheat their way through tests. Still worth it to prevent regressions.

06 · Library 3: Gary Tan (gstack)
YC CEO. Opinionated, Rob calls it overengineered. Standout: office-hours skill, 6 forcing questions about your startup idea.

07 · Library 4: Everything Claude Code
183K stars, 170 contributors. Memory, continuous learning, verification loops, sub-agent orchestration, heavy security focus.

08 · Spec-based libraries
BMAD: enterprise BA to PM to architect pipeline. SuperPowers: lightweight, Rob's favorite. OpenSpec, GSD, Speck Kit also covered.

09 · Sponsor: CodeRabbit Atlas
Atlas: layered PR diff view. Breaks code into data shape, business logic, testing layers with AI summaries that update as you scroll. Free for limited time.

10 · The Simple Skill Stack
The portable 5-step loop: Research (ask mode), Prototype (design mode, frontend only, dummy JSON), Plan (native plan mode), Build (vertical slices), Test (automated + human smoke test).

11 · Build your own system
Start with natural language prompting. Only create a skill when the agent makes a repeatable mistake. Keep skills to a few short paragraphs. Skills.sh for team sharing.

12 · How you win as a builder
Your bespoke harness built over time on your specific codebase is the moat. Skills are documentation and go stale, so be selective.
Lines worth screenshotting.
- Every major skill library — Gary Tan, Matt Pocock, Adi Asmani, Everything Claude Code — converges on the same five-phase loop: Research, Prototype, Plan, Build, Test.
- A skill is not just a prompt in a folder; it also contains a description the model checks every invocation, step-by-step instructions, and tools like scripts and API calls.
- Prototyping the frontend before the backend dramatically speeds the build phase because the agent has a concrete visual target and doesn't slow down on database decisions.
- Every framework advocates for test-driven development so that new AI-generated code can't silently break what was previously working.
- The most powerful skill system is bespoke — built incrementally for your own workflows — not a cloned repo from someone else's GitHub.
- Gary Tan's YC-CEO office-hours skill forces six founding questions before any build starts, which differentiates builders who know what to build from those who are just fast.
- Adi Asmani's approach breaks every build into vertical slices the agent can handle and verify one at a time rather than taking on the whole system at once.
- The bMAD framework is enterprise-grade, modeling a business analyst, product manager, and senior architect working together — too heavy for solo builders, useful for teams.
- Everything Claude Code hit 182,000 GitHub stars, making it one of the fastest-growing open-source projects ever — demonstrating the market demand for shareable skill libraries.
- Spec-based systems and skill-based systems overlap heavily; the real differentiator is whether you understand what's inside each skill well enough to debug when it fails.
- Breaking a massive monolithic skill into smaller composable ones makes failures easy to locate and improvements compound across everything that uses the shared pieces.
- The hybrid approach — taking principles from multiple libraries and building your own lightweight harness — outperforms any single off-the-shelf skill system for your specific context.
Stop cloning repos. Build the loop.
The 5-step loop is all you need from any skill library, and you don't have to install anything.
- Run Research as an ask-mode interview session before every build.
- Add a Prototype session type in JoeFlow that enforces frontend-only, dummy-JSON constraints.
- Lean on native plan mode in Claude Code — it already creates phase-based markdown plans without a skill.
- Only write a new SKILL.md when the agent makes the same mistake twice — not preemptively.
- Keep every skill to a few short paragraphs. Bloated skills eat context and confuse the model.
- Steal Gary Tan's office-hours pattern: 6 forcing questions before any build session begins.
- Your harness is your moat — the longer you build on one codebase, the more unreplicable it becomes.
Terms worth knowing.
- Skill
- A reusable natural-language prompt stored in a special SKILL.md file with front matter (name, description) that an AI coding agent loads automatically so it knows when and how to apply that capability.
- Front matter
- A small block of metadata at the top of a markdown file — typically name and description — that tools read to index or activate the file without parsing the whole body.
- Skill library
- A shared collection of prebuilt skills, usually hosted on GitHub, that developers install into their AI coding agent to standardize how it researches, plans, builds, and tests code.
- Agent harness
- The surrounding scaffolding — prompts, skills, modes, memory, and verification loops — that shapes how an AI coding agent behaves on a project, as opposed to the raw model itself.
- Spec-based development
- A workflow where you first write a detailed specification of what should be built, then have the agent produce a plan and code strictly against that spec rather than improvising from a one-line request.
- Vertical slice
- A small end-to-end piece of a project that touches every layer (UI, logic, data) so it can be built and verified on its own before moving to the next slice.
- Test-driven development
- A practice where you write automated tests describing the expected behavior before writing the implementation, then make code changes until those tests pass.
- Context window
- The maximum amount of text — instructions, files, conversation — a language model can consider at one time. Loading too much irrelevant material crowds it out and degrades the model's responses.
- Sub-agent orchestration
- A pattern where a primary agent delegates subtasks to specialized secondary agents (planner, coder, reviewer, etc.) and coordinates their outputs into one workflow.
- BMAD
- An enterprise-oriented agent framework that simulates a full software team — business analyst, product manager, architect — collaborating in sequence to enforce a formal software development life cycle.
- Superpowers
- A lightweight community skill library for AI coding agents focused on a small, opinionated set of prompts for planning, building, and reviewing code.
- Pull request
- A proposal on a code-hosting platform like GitHub to merge a branch of changes into the main codebase, giving teammates a place to review the diff and discuss before it lands.
- Diff
- A side-by-side or inline view of what changed between two versions of a file, with removed lines and added lines highlighted so reviewers can see exactly what a change does.
- CodeRabbit
- An AI code review tool that analyzes pull requests, summarizes the changes in plain language, and surfaces suggested fixes inline so human reviewers can move faster.
- Atlas (CodeRabbit)
- A CodeRabbit feature that reorganizes a pull request's diff into logical layers — data shape, business logic, tests — and adds contextual AI summaries alongside the code as you scroll.
- Ask mode
- A mode in AI coding tools where the agent only asks clarifying questions and discusses the work instead of editing files, used to nail down requirements before any code is written.
- Plan mode
- A built-in mode in tools like Claude Code, Codex, and Cursor that produces a structured markdown plan — phases, todos, verification steps — before the agent is allowed to start changing code.
- Prototype mode
- A working style where the agent is told to build only the front-end with mock data — wireframes, navigation, dummy JSON — so the interface can be validated before any backend logic is written.
- ASCII diagram
- A diagram drawn with plain text characters that an agent can produce instantly inside a chat or markdown file, useful as a quick wireframe or architecture sketch.
- Lint
- An automated code check that flags style violations, syntax errors, and likely bugs without actually running the program, typically run as part of a build pipeline.
Things they pointed at.
Lines you could clip.
“I went to all the major skill libraries... and distilled all the key ideas down into a couple of prompts, skills, and patterns that you can reuse on every project over and over.”
“I don't rely heavily on spec-based systems. I just go with something a little bit lightweight and bespoke myself.”
“I think the best system is going to be the one you end up building yourself.”
“When you do create a skill, it's only because the agent has messed up in some way or you want to give it very bespoke information about your codebase.”
“Your agent harness, your set of skills that has been built up over time working with a particular codebase — that's how you really differentiate as a software developer.”
Word for word.
The bait, then the rug-pull.
Rob Shocks did the homework so you don't have to. He spent almost two years working with agents, surveyed every major skill library in the ecosystem and came back with a single decision rule: five steps, no repo to clone.
Named ideas worth stealing.
The Simple Skill Stack
- Research
- Prototype
- Plan
- Build
- Test
- Polish
The 5 (+ 1 optional) step agentic development loop. Research = ask mode interview. Prototype = design mode frontend only. Plan = native plan mode. Build = vertical slices. Test = automated + human. Polish = simplify pass with different model.
Agent Harness Architecture
- Planning
- State Management
- Memory
- Tool Runtime
- Skills
- Evaluators
- Reasoning Engine (LLM)
Skills are one component inside the full agent harness, not the whole thing. Common mistake: treating skills as the harness itself.
Agentic Development Life Cycle (ADLC)
The agentic equivalent of SDLC. Includes skill management and harness management as new disciplines alongside traditional dev stages.
office-hours (Gary Tan)
A skill that forces 6 YC-style questions about your startup idea before building. Rob rates it the best individual skill across all libraries.
grill-with-docs (Matt Pocock)
Pre-loads domain vocabulary, framework terminology, and ADRs into model context at session start. Prevents agent from drifting outside your project language.
Design / Prototype Mode
- Frontend only, no backend logic
- Use dummy JSON for all data
- Link all components for navigation
- Make buttons responsive
- Do not connect to backend logic
Isolated frontend-first pass before any backend work. Agent builds a clickable wireframe with mocked data, giving a clear target for the backend phase.
How they asked for the click.
“If you found this useful, hit the subscribe button.”
Clean single-line ask at the end. No newsletter pitch, no sponsor repeat. Low-pressure.




































































