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lucaslimafonslucaslimafons/skills/feature-deep-dive/SKILL.md

feature-deep-dive

Skill1 starsChanged 7 months agoMITView on GitHub

Deep-dive research and approach analysis before building a feature. Takes one specific use case, screen, or interaction; researches how top, currently-popular apps and products handle it using live web search; then grounds concrete, buildable recommendations in THIS project's actual codebase, design tokens, and conventions. Operates without assumptions — when scope, intent, or a product decision is ambiguous, it stops and asks rather than guessing. Use this whenever the user wants to scope, explore, or decide how to approach a feature before any code is written, or says things like "how should we do X", "how are the top apps doing Y", "analyze this use case", "deep dive on Z", or "research this before we build". Lean toward triggering for any "how should we approach this / how do others do this" question that precedes implementation.

The file

We split this skill into the rules it gives an agent

9 rules. About 0 are common, 7 are distinctive, and 2 are very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈7

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 2

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Distinctive:

    Ask early, before you've spent effort researching down the wrong path.

    line 35
  2. Distinctive:

    Don't assume the stack or conventions — read them.

    line 49
  3. Very specific:

    Read the project's own engineering reference / conventions if present (a CLAUDE.md, an AI_CORE_CONTEXT.md, README, docs/).

    line 52
  4. Distinctive:

    Use live web search to find how leading, currently-popular apps and products handle this exact use case — not what you remember, but what's …

    line 63
  5. Distinctive:

    Look for the established pattern, the emerging standard, and notable variations.

    line 67
  6. Distinctive:

    Prefer concrete, recent sources and cite them so the user can dig deeper.

    line 68
  7. Distinctive:

    Keep it buildable — the natural next step should be a plan or implementation, not another layer of abstraction.

    line 82
  8. Distinctive:

    Default to an inline analysis in the conversation.

    line 87
  9. Very specific:

    If the user asks to save it, write a markdown file — default docs/research/<feature>.md, or a path they specify.

    line 92

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Feature Deep-Dive

Turn a fuzzy "I want to build X" into a grounded, no-assumptions plan of attack — informed by how the best apps in the wild solve the same problem, and by what already exists in this codebase.

The output is research and a recommended approach. It is not code. Resist the urge to start implementing — the whole point is to think first so the eventual build is fast and right.

Core principle: no assumptions

This is the part that matters most. The user would much rather be asked than guessed at. Whenever you hit a fork where you'd otherwise have to assume — the exact scope, who the feature is for, an unstated product decision, which of two readings of the request they mean, a constraint you can't verify — stop and ask a short, concrete question instead of quietly picking one.

Ask early, before you've spent effort researching down the wrong path. A useful rule: if getting it wrong would waste the research, ask now; if it's a minor detail you can caveat, state the assumption explicitly and keep going. Either way the user should never be surprised by a silent guess.

Workflow

1. Clarify the target

Restate the specific use case in a sentence or two so the user can confirm you're both looking at the same thing. If the request is broad ("improve onboarding"), narrow it to the concrete slice worth analyzing and confirm that slice. Surface any unknowns here, up front.

2. Discover the project

Don't assume the stack or conventions — read them. Before researching solutions, understand the ground you're building on:

  • Identify the platform and framework (package.json, lockfiles, config files).
  • Read the project's own engineering reference / conventions if present (a CLAUDE.md, an AI_CORE_CONTEXT.md, README, docs/).
  • Find the design system / tokens and existing UI primitives so recommendations fit what's already there rather than fighting it.
  • Locate any existing code touching this use case — often part of the answer is already in the repo.

This step is what keeps the final recommendation grounded in this project instead of generic advice.

3. Research how the best apps do it

Use live web search to find how leading, currently-popular apps and products handle this exact use case — not what you remember, but what's current. For a mobile project that means top mobile apps; adapt to whatever platform you detected in step 2.

  • Look for the established pattern, the emerging standard, and notable variations.
  • Prefer concrete, recent sources and cite them so the user can dig deeper.
  • Capture why a pattern won, not just what it looks like — the reasoning transfers across contexts far better than the surface design.
  • Flag where "best practice" is genuinely contested, so the user can decide rather than be handed a false consensus.

4. Synthesize a recommended approach

Bring the two threads together: here's how the best apps solve it, here's what this codebase already has, so here's how we should approach it.

  • Give a concrete recommendation, plus one or two alternatives with their tradeoffs.
  • Map it onto real files, components, and tokens in this project.
  • List every assumption you had to make and every open question still blocking a confident build.
  • Keep it buildable — the natural next step should be a plan or implementation, not another layer of abstraction.

Output format

Default to an inline analysis in the conversation. That's how this is used most of the time and it keeps the discussion moving. Structure it clearly around the four stages: Use case → Project grounding → How the top apps do it → Recommended approach + open questions.

If the user asks to save it, write a markdown file — default docs/research/<feature>.md, or a path they specify. Don't save proactively; only when asked.

To hand the analysis to a different session to act on, don't invent a temp-file scheme here — point the user at the handoff skill, which is built for exactly that.

What good looks like

  • The user is never surprised by a silent assumption.
  • Recommendations name real files, components, and tokens — not generic advice.
  • Research reflects what top apps do now, with sources, not vague memory.
  • It ends with a clear, buildable direction and an explicit list of anything still open.

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