1. Home
  2. Library
  3. AI Tooling Crash Course for Developers
  4. README
AI TOOLING CRASH COURSE

Start here. Read in this order.

Nineteen deep-dives on working with AI coding tools. You do not need to read them all, and you do not need to read them in file order. Follow the trail below: the basics first, then the working habits, then trust and safety, then the niche stuff.

Begin: what even is an LLM?

The trail

Four zones, easy to hard. Stop whenever you have what you came for.

Zone 1: The basics start here

What the thing is, the words people use, and how not to burn money.

  1. 1How LLMs actually workThe next-word machine, in plain terms. Read this first.
  2. 2Harness & context vocabularyThe shared words: harness, context engineering, repository legibility.
  3. 3Sessions & token economicsWhy long chats get worse and pricier, and how to save tokens.
  4. 4Prompt engineeringWriting the actual words you send the model.

Zone 2: Working with an agent daily habits

Set the agent up well and give it good instructions.

  1. 5Base instruction filesCLAUDE.md, AGENTS.md and friends: what goes in, what does not.
  2. 6Planning before implementationWhen to plan, when to skip it, and how to check a plan.
  3. 7Skills & marketplacesReusable instruction packs and where to find them.
  4. 8Subagents & delegationHanding work to a helper with its own fresh context.
  5. 9MCPConnecting the model to live tools and data.
  6. 10Memory & progress ledgersMaking an agent remember across sessions without magic.

Zone 3: Trust & safety before you ship

Checking the work, and not getting burned by what you install.

  1. 11Review & verificationWhy self-review is weak and what to do instead.
  2. 12Security & supply chainReal incidents and a low-effort checklist.
  3. 13Scanning third-party skillsScanners exist, disagree, and can be fooled.
  4. 14Agent sandboxingKeeping a bad action contained to a box.

Zone 4: Going deeper niche, optional

Worth it once the earlier zones feel routine.

  1. 15Loop engineeringAgent loops that finish instead of drifting.
  2. 16Second brain & RAGSearch over your own code, decisions and notes.
  3. 17Local models & hardwareWhat actually runs on a consumer GPU.
  4. 18ACP, A2A & protocolsHow the agent protocols relate to MCP.
  5. 19Graph engineeringMany agents as an explicit network. Newer, less settled.
  6. 20Personal harness architectureConcrete build proposals for your own setup.

Side quests

The full topic survey

Topic Index — What's Actually Agreed On (2026)

A survey, not a shopping list. Each topic below states what's settled vs. contested in the field, then links to the deep-dive doc(s) that cover it in this repo — or says plainly if no deep-dive exists yet. Personal reactions/mark-labels from the original pass are kept separately in local/stage-0-raw-notes.md (gitignored, not shareable content — this file is the shareable version).


1. Context/memory files

Every major agentic coding tool now reads a plain-markdown instruction file at project root before acting: CLAUDE.md (Claude Code), AGENTS.md (cross-tool convention, adopted by Codex CLI, Cursor, others), .github/copilot-instructions.md (Copilot). Settled pattern: keep it short, pointers not prose, and treat provider-specific files as thin wrappers around one provider-agnostic source (AGENTS.md) rather than duplicating content per tool. AGENTS.md is the primary source of truth, not CLAUDE.md — provider-specific content is the exception, only for what a tool genuinely can't get any other way.

Deep dive: base-instruction-files.md — governance/adoption verification, per-provider loading mechanics, the (contradicted) 200-line-length guidance, nested/local-override patterns, ADR-as-context status, drift tooling, and anti-patterns including a confirmed prompt-injection vector via cloned repos' own AGENTS.md files. No pick made.

Not the same topic as #10 — that's session/progress ledgers, cross-project memory of decisions. This is the base instruction file itself. Open item: ~/.claude/CLAUDE.md hasn't been reviewed against this doc's findings yet, see _architecture/BACKLOG.md. Also open: no dedicated doc yet for "per-feature/per-quirk architectural context" — related but unresolved by harness-engineering-vocabulary.md and personal-harness-ARCHITECTURE.md, blocked pending a pick from item 10.

2. Prompt & skill libraries

Anthropic's SKILL.md format (a folder with a markdown file plus optional scripts/resources, progressively disclosed into context only when triggered) is a de facto standard for Claude Code and is being mirrored by other tools' "custom command" systems. The unsettled part: whether skills should be personal, project-local, or org-distributed as plugins — practice varies by how much the author expects reuse.

Deep dive: skill-libraries-and-marketplaces.md — spec state, anti-patterns, marketplaces, individual atomic skills vs. libraries. Reference lists: _ai-tooling-recommendations.md.

3. Session & token economics

Consensus: long-running sessions degrade output quality ("context rot") well before they hit the hard token limit, because irrelevant history competes for the model's attention on every turn. Agreed mitigations: one coherent unit of work per session, proactive /compact//clear, and prompt caching (rewarding session shape — stable prefix, volatile content appended — over raw brevity). Still evolving: automated context-management hooks that decide for you when to compact.

Deep dive: session-and-token-economics.md — caching cost mechanics, compaction vs. fresh, subagent token impact by provider (including a firsthand corporate-environment audit).

4. Subagents / multi-agent delegation

Agreed use case: delegating work whose intermediate tool output you don't need to keep — broad exploration, isolated research, parallel independent tasks. Agreed anti-pattern (debated in degree, not direction): using multiple agents as a substitute for review quality ("ask 3 agents, take the majority") — correlated error, not independent verification. The distinction: fresh-context subagent for scope (well-supported) vs. multi-agent voting for confidence (contested).

Deep dive: subagents-and-delegation.md — cross-provider status, bounded-roles-vs-swarms pattern.

5. MCP (Model Context Protocol)

Adoption moved from experimental to mainstream fast: by mid-2026, MCP-backed agents are in production at the large majority of enterprise AI teams tracked in industry surveys. In restricted corporate environments, the documented workaround is packaging the same capability as an Agent Skill that wraps a direct API/CLI call instead of running an MCP server. Three-primitive framing gaining traction: Skills for reusable capability + know-how, MCP for governed live connectivity, CLI/local execution underneath both.

Deep dive: mcp-model-context-protocol.md — servers, security, CLI-vs-MCP tradeoff. Related: protocol-landscape-acp-a2a.md (how MCP relates to ACP/A2A).

6. Hooks / automation triggers

Settled as a category: hooks (shell commands firing on tool-call, session-start, session-end, etc.) are the accepted mechanism for deterministic guardrails an LLM shouldn't be trusted to self-enforce. Not contested that they're useful; what's a matter of personal taste is how much automation to hang off them.

No dedicated deep-dive doc yet — a lighter-pass topic, not yet researched beyond this baseline note.

7. Local model use

Converging, previously contested: for a single consumer GPU in the 8GB class, the realistic role is opportunistic — batch/offline jobs where latency doesn't matter — not a default coding-assistant tier. Frontier cloud models still substantially outperform anything that fits in 8GB VRAM for actual coding/reasoning work.

Deep dive: local-model-hardware-fit.md — hardware fit, quantization tradeoffs, Ollama vs. alternatives.

8. Review discipline

Agreed: self-review by the same model/context that wrote the code is weak evidence, and multi-agent "consensus" review is correlated rather than independent for the same reason as item 4. The stronger pattern — sometimes called a cold-start or fresh-context critic — is a separate agent with no shared conversation history, forced into a typed verdict, ideally from a different model family. Demanding pasted command output over claimed correctness is close to universal agreement.

Deep dive: review-and-verification-tooling.md — off-the-shelf/IDE-native review tooling, open-source review agents.

9. Dotfiles / portability

The mainstream answer is a dedicated dotfile manager (chezmoi being the most-referenced, with GNU Stow and plain symlink scripts as lighter alternatives), trading a steeper tool for templated per-machine divergence.

Decided against, 2026-09-01 — see Dependencies. No dotfile manager and no binaries in the shippable layer. A binary fails on a locked corporate machine, which is exactly where the stack has to work, and the divergence problem it solves is already handled by the _jookoi- prefix plus one vault per environment. Applying the stack is a manual copy.

No dedicated deep-dive doc — the pick closed the topic rather than a research pass doing it.

10. Personal cross-project memory/ledger

No single agreed tool here — a real gap, not just an unresearched one. Candidates named: Claude Code's own built-in memory system, plain dated journal files, a personal notes vault (Obsidian-class), periodic extraction scripts mining AI session transcripts, gitignored per-repo notes.

Deep dive: memory-and-progress-ledgers.md — full evaluation of all candidates, no pick made yet. 2026-08-23 addition: storage/vault-layer research for the corporate-environment-viable design (§8 of that doc) — most named vault products fail the corporate no-native-binaries/no-MCP filter; the closest named prior art is the Cline-style "Memory Bank" pattern, not a vault product.

11. Usage analytics / self-assessment tooling

Confirmed: AI Engineering Fluency (VS Code extension, author Rob Bos / rajbos) — reads local session logs from VS Code, Copilot CLI, Claude Code, Gemini CLI, Cursor and others, surfaces token usage/cost/usage-pattern insights in the editor status bar, local-first. Beyond this one extension, the category is small and not yet consolidated.

No dedicated deep-dive doc — confirmed via this baseline pass, open follow-up (more options in this category) not yet pursued.

12. Security

The volume of new repos/scripts/skills available makes it tempting to just install and use things, but shipping malicious code inside them is easier than ever — closer to old-school piracy risk (grab a pile of loot, find a surprise inside) than typical package-manager trust.

Deep dive: security-and-supply-chain.md — verification checklist, real 2026 incidents (ClawHub/OpenClaw, Snyk ToxicSkills), low-effort solo-dev practices.

13. Frontend debugging, browser interaction, AI integration tooling

No dedicated stage-1 deep-dive doc — this ground was covered instead through direct verification passes on user-supplied tool lists. See _ai-tooling-recommendations.md → "Design-to-code / browser verification tooling" (chrome-devtools-mcp, browser-use, Skyvern, Stagehand, etc.).

14. IDE inline completion and general tooling (WebStorm / VS Code)

No dedicated deep-dive doc yet — a lighter-pass topic, not yet researched beyond this baseline note.


Surfaced later (not part of the original 14 topics)

These emerged mid-process from later research/conversations, not the original Stage 0 pass:

  • harness-engineering-vocabulary.md — harness engineering, context engineering, repository legibility as a connected vocabulary/completeness pass. Agent loops split out separately, see below.
  • loop-engineering-agent-loops.md — building an agent loop that actually finishes instead of drifting or self-reporting false completion.
  • prompt-engineering.md — the base layer underneath every other topic here: writing the actual words sent to the model. Skeleton doc, resource curation still pending.
  • personal-harness-ARCHITECTURE.md — concrete build proposals: deterministic context bundling, capability lifecycle management, task state as a dependency graph, async/non-blocking long-running commands.
  • protocol-landscape-acp-a2a.md — ACP, A2A, CLI-vs-MCP for local capabilities.
  • agent-sandboxing.md — code-execution sandboxing, Claude Code's /sandbox command.
  • dev-scoped-second-brain-rag.md — RAG over your own codebase/ADRs/notes (not general life-organization).
  • graph-engineering-multi-agent-coordination.md — coordinating multiple agents/loops as an explicit node/edge graph (LangGraph), and the separate knowledge-graph-vs-vector-RAG sense of the term. Newer, less-settled terminology, sourcing flagged as provisional.
  • Coding-agent harness/model landscape — kept as reference tables in _ai-tooling-recommendations.md, not a separate topic doc (no distinct educational content beyond listings).
  • stack-distribution-ARCHITECTURE.md — how the shippable stack layer (AGENTS.md/skills//prompts//utility-scripts/) should be organized and distributed: skill-sync mechanism, drop-in-folder vs. installer, root-AGENTS.md collision risk. No pick made — requirements + open research questions only, 2026-08-27.
  • ../../_architecture/plans/2026-08-30-jookoi-paper-trail.md — the memory system: per-project context file set, feature-local CONTEXT.md, and a personal vault repo for repos where committing isn't allowed. Not a researched topic doc — the user's own design, with a prior-art scan (2026-08-27) and a full spec (2026-08-30). Lives in _architecture/plans/, not here, deliberately.

Surfaced from cross-repo consolidation (not part of the original 14, added 2026-08-23)

  • planning-before-implementation.md — evidence-based planning methodology: when to skip planning, elicitation, decomposition, critique (cold-start review, premortem), when to skip heavyweight spec-driven ceremony. Ported from the old Cowork-session location — this was the one file that never made it across when the projects split.

Surfaced 2026-08-23, no deep-dive yet: where agents actually work — global folders, session logs, temp worktrees

Distinct topic, flagged by the user, not yet researched. Coding agents don't only touch the project directory — they keep session logs/temp files/state in global per-tool folders outside the repo (e.g. ~/.claude/), and some workflows have an agent do its actual work in a temporary directory or git worktree entirely outside the visible project, branching and merging back later. This is real "AI basics" territory — someone new to agentic tooling needs to know this is happening, where to look, and what it means for review/trust. Likely touches token-efficiency and session-economics topics (3) but is its own subject, not a subset. Do not start researching this yet — log only. See _architecture/BACKLOG.md for the scoped follow-up task.

Surfaced 2026-08-23, no deep-dive yet: scanning/verifying third-party skills and repos for malicious content

Distinct from topic 12 (Security) above, which covers verification practice and named incidents generally. This is narrower and more concrete: an actual tool/process pick for scanning a specific skill, plugin, or repo for malicious prompts/code before adopting it — not yet researched as its own question. Check security-and-supply-chain.md when it's reviewed (still unread) for whether it already answers this; if not, this needs its own research pass.

Resolved 2026-08-23 (cowork research pass): deep-dive doc now exists — skill-scanning-and-verification.md. Confirms security-and-supply-chain.md does not already answer this (that doc covers general practice/incidents, not a specific scanning tool/process). Key finding: purpose-built scanners are now plentiful (NVIDIA SkillSpector, Snyk agent-scan, Cisco skill-scanner) but largely disagree with each other and are evadable — treat any single scan result as one weak signal, not a verdict. No pick made.

Topics to add:

  • 0 how do llm's actually function under the hood explained semi-eli5 style ? (way too many people, incl. devs not understanding the topic)

Sources

  • Anthropic Claude Code documentation and this session's own harness behavior (memory system, hooks, subagents, SKILL.md, prompt caching) — primary source for items 1–6, 8.
  • Industry survey coverage of MCP enterprise adoption, July 2026 (andrew.ooo, digitalapplied.com, a2a-mcp.org roadmap coverage) — item 5.
  • Xebia engineering blog and DevOps Journal (2026) on the "AI Engineering Fluency" VS Code extension by Rob Bos (rajbos) — item 11.
  • chezmoi project (public repo, active maintenance, cross-platform templating) — item 9's baseline. Evaluated and rejected, see _architecture/ARCHITECTURE.md § Dependencies.
1 / 4