Claude Code 101

• QuestionWhat is "Place hook on correct event"?Tap to revealAnswerPick the hook event by what your trigger fires on: blocking → PreToolUse · per-task → Stop · per-tool-call → PostToolUse · once at boot → SessionStart.
• QuestionIn "Place hook on correct event", explain:Tap to revealAnswerHooks run in the harness. The model can't refuse, forget, or interpret them.
• QuestionIn "Place hook on correct event", explain:Tap to revealAnswerPreToolUse is the only blocking event. Guardrails live there, period.
• QuestionIn "Place hook on correct event", explain:Tap to revealAnswerPostToolUse = per individual tool call. Stop = per task / turn. Pick by granularity.
• QuestionIn "Place hook on correct event", explain:Tap to revealAnswerTrigger phrasing maps to event: 'before tool' → PreToolUse · 'after task' → Stop · 'after each call' → PostToolUse · 'on boot' → SessionStart.
• QuestionAnalogy for "Place hook on correct event":Tap to revealAnswerThink of the model as a chef and the harness as the kitchen's safety officer. Hooks are the officer's standing rules. 'Stop the chef before they pick up the knife' has to fire before the action — that's PreToolUse. 'After every dish goes out, wipe the counter' fires once per dish leaving — that's Stop, the per-task event. 'After every utensil is used, sanitize it' fires every time a utensil touches food — that's PostToolUse. Pointing the rules at the wrong moment is what makes the kitchen unsafe.
• QuestionWhat is "Predict permission cascade"?Tap to revealAnswerSettings cascade in order: Enterprise > CLI > project-local (.local.json) > project-shared (.json) > user. Higher always wins. Local-project beats shared-project.
• QuestionIn "Predict permission cascade", explain:Tap to revealAnswerPrecedence: Enterprise > CLI > project local > project shared > user.
• QuestionIn "Predict permission cascade", explain:Tap to revealAnswerHigher layers can lock fields lower layers cannot override.
• QuestionIn "Predict permission cascade", explain:Tap to revealAnswerLocal project (`.local.json`) wins over shared project (`.json`). Inverse of common guess.
• QuestionIn "Predict permission cascade", explain:Tap to revealAnswerFirst explicit decision in the cascade wins; absence = pass-through.
• QuestionAnalogy for "Predict permission cascade":Tap to revealAnswerThink of it like a chain of approvers. The boss (Enterprise) overrides everyone. CLI flags are 'just for this meeting.' Your personal note on the project (local) overrides the team note (shared). Your default user prefs are last.
• QuestionWhat is "Route rule (CLAUDE.md / reference / skill / slash / hook)"?Tap to revealAnswerPick by invocation model and trust: always-on advice → CLAUDE.md; on-demand by user → slash or skill; deterministic enforcement → hook; on-demand reference → reference/.
• QuestionIn "Route rule (CLAUDE.md / reference / skill / slash / hook)", explain:Tap to revealAnswerDecision axes: invocation frequency, trust requirement, instructions vs capability.
• QuestionIn "Route rule (CLAUDE.md / reference / skill / slash / hook)", explain:Tap to revealAnswerCLAUDE.md = always-on advice. reference/ = on-demand context. Skill = user-invoked instructions. Slash = user-invoked one-shot. Hook = harness-enforced.
• QuestionIn "Route rule (CLAUDE.md / reference / skill / slash / hook)", explain:Tap to revealAnswerHard rules and automation → hook. Always-on advice → CLAUDE.md. On-demand workflow → slash or skill.
• QuestionIn "Route rule (CLAUDE.md / reference / skill / slash / hook)", explain:Tap to revealAnswerInstructions are not the same as capabilities. Capabilities go in tools / MCP.
• QuestionAnalogy for "Route rule (CLAUDE.md / reference / skill / slash / hook)":Tap to revealAnswerIt's like deciding where to put a rule at work. Standing rule? Office handbook (CLAUDE.md). Reusable workflow? Templated form (slash). Specialist procedure? Trained skill on the menu (skill). Mandatory pre-flight check? A locked door with a badge reader (hook).
• QuestionWhat is "Author slash command"?Tap to revealAnswerA slash command is a saved prompt you invoke with `/name`. Live in `.claude/commands/` (project) or `~/.claude/commands/` (personal). Frontmatter for metadata, body for the prompt.
• QuestionIn "Author slash command", explain:Tap to revealAnswerSlash command = reusable prompt expansion, invoked via `/name`.
• QuestionIn "Author slash command", explain:Tap to revealAnswerProject: `.claude/commands/<name>.md` (checked in). Personal: `~/.claude/commands/<name>.md`.
• QuestionIn "Author slash command", explain:Tap to revealAnswerFrontmatter: description, argument-hint, allowed-tools. Body = the prompt template.
• QuestionIn "Author slash command", explain:Tap to revealAnswerUse slash for prompt-only reuse. Use Skill when you need assets / discoverability.
• QuestionAnalogy for "Author slash command":Tap to revealAnswerThink of a slash command as a text-expansion shortcut that the AI uses. You type `/release-notes`, the AI sees the full pre-written prompt.

1. 1Outline the core idea

   Analyse~10 min

   In your own words, outline the central idea of "Place hook on correct event". Aim for one paragraph, no jargon you haven't earned.

   Done when: A non-expert could read your paragraph and explain it back to you.

   Re-read the source concept

2. 2Solve it to a real situation

   Apply~15 min

   Find a real situation from your own work / life where "Author slash command" applies. Solve the idea — describe the situation, the move you'd make, and the alternative you considered first.

   Done when: You can name a specific situation (not a hypothetical), state your move, and explain the trade-off in one paragraph.

   Re-read the source concept

3. 3Teach it back

   Evaluate~5 min

   Pick someone (a colleague, a peer, a rubber duck) and explain the section to them in under 5 minutes. Use your own example, not the one from the lesson.

   Done when: Your listener can repeat the core idea + the trade-off back to you without prompting.

Why this matters. Reading + quizzing prove recall; applying it in a real situation is the only evidence of transfer. Treat at least one of these as non-negotiable before you move on.