AI Sprint: Windsurf & Devin — Day 1 (Vibe to Agentic: GitHub as Pizza, the Four Spec Concerns, and the IDE Lineage)

Vibe coding: you explain a requirement informally, the AI builds, every new feature is another chat turn — 'you don't have clarity; you're trying to get there.' The platforms named for it: Bolt, Lovable, Emergent. Agentic coding: you SPECIFY — 'in your head it is absolutely clear what you want to build. You queue the specification, and sometimes even a swarm of agents builds your app.' The kitchen version: grandma's recipe ('this much... then this much... feel it, you know when it's done') is a conversation — always decent, never replicable; the MasterChef recipe ('150 degrees, 12 minutes — not 10, not 15') is a specification — perfectly replicable, and fragile: 'any one step goes here and there, your dish is off.' Neither is 'better'; they're methods — but 'if you're trying to become an AI generalist, start making the transition.'

The honest nuance: 'the lines can be blurred — you could be vibe coding in Cursor and attempting agentic coding in Lovable.' The transition has three steps: get comfortable with GitHub, learn to write good specs, then learn agentic orchestration (Windsurf/Devin). And the fragility of specs is exactly why the four concerns (edge cases, auth, rate limits, error handling) exist — specification precision cuts both ways.

The restaurant: the repo is the recipe book; the chef is the maintainer. Sous-chefs don't edit the master recipe — each gets a COPY (branch A1, A2, A3) and experiments freely: 'working on the copy doesn't affect the main recipe... the main pizza keeps getting made for customers while the sous-chefs experiment.' When a change proves out, the sous-chef ASKS — 'dear chef, I made this change to step 3, taste it yourself' — a PULL REQUEST; the chef tastes and MERGES, or REJECTS WITH FEEDBACK ('I like your thought process, but the pizza is getting too soggy' — the good chef's rejection carries the reason). A FORK is the sous-chef opening his own restaurant with a copy of the recipe: changes never flow back automatically, though a kind chef may later offer his improvements ('you might accept, you might not'). A COMMIT is the chef's hidden copy — the saved-game checkpoint: 'anytime disaster happens, I go back to my previous commit and restore... you died at level 4, you come back to level 4, not level 1.'

The purpose is stated plainly: 'right now the AI will do all of this for you — I'm explaining the concept so you understand what is happening behind the scenes,' because agentic coding lives in branches, PRs, and commits whether you see them or not.

EDGE CASES — the boundary where cooked becomes burnt: 'your recipe works in your new oven; your friend's old oven overheats — pizza spoiled.' You cannot anticipate all edge cases ('the room agreed: 0% confidence in a foolproof recipe'), but 'most of them you can' — the iPhone-SE-through-original spread for a mobile app — and mapping the common ones is what separates engineering from hoping. AUTHENTICATION vs AUTHORIZATION — the cinema: the ticket (authentication) gets you in; the seat class (authorization) is what you may use. The under-taught point: auth exists for PERSONALIZATION as much as security ('how does the app know you're on page 27?'), local storage dies with crashes and deletions, and the workflow rule is BUILD AUTH LAST — 'make it the last feature before you hand it to a user, so you're not logging in every test cycle.' RATE LIMITS — the houseguest quota ('only two pieces of pizza for you; the rest is for the guests'): APIs throttle per tier even when paid, the live example being 'Anthropic rate-limited OpenClaw'; and documentation has become AGENT-FRIENDLY — ElevenLabs' copy-page/open-in-Claude buttons mean 'this is what your agent reads, not you.' ERROR HANDLING — the out-of-syllabus question: specify behavior per known error ('error 1 do this, error 2 do this'), give users useful invalid-input messages instead of blank screens, and close with the mother's final exception: 'anything you don't know how to act — ask me.'

In the beginning: VS Code, open source — so people forked it into companies: Cursor, Windsurf, Kiro (Amazon), Trae (ByteDance). Then the split that created two lineages: Google 'purchased the founders with the core team' of Windsurf (~8-20 of 100 people, with the IP as of that date) and built ANTIGRAVITY from that snapshot. The remaining ~80 people kept building Windsurf — until COGNITION, makers of the autonomous agent DEVIN, acquired the company: 'Windsurf became Windsurf 2 with Devin integrated — a convergence.' So Antigravity and Windsurf 2 are siblings from one codebase, diverging on purpose: 'there are similarities, but they try to be quite different from each other.'

The teaching stance that frames every tool session: 'I'm showing you different types of pizza. Taste it and decide. Don't ask me which pizza is best — I'll tell you how this one differs from that one. Take it, taste it, or leave it.'

The tour, planted for Day 2's build: Windsurf 2 looks like every VS Code descendant ('everyone is based out of Visual Studio Code only... mostly like Antigravity'); the agent is CASCADE (Cmd+L — 'like Composer in Cursor, agent mode in Antigravity; everybody works the same way'). The distinguishing feature is the MODEL MENU as a price ladder: ADAPTIVE at ~$0.5/M auto-balances quality and cost per request ('a Windsurf feature — don't think adaptive exists in Antigravity'); SWE 1.6 FAST is the in-house coding model at the cheap end; Kimi K2.6 rides the FREE tier ('very similar to Claude Code — you don't have to worry'); DeepSeek sits mid-ladder; Claude Opus tops it and requires YOUR OWN API key ('they don't have an integration — you connect the key'). Setup is conversational end to end: 'make a simple repo in GitHub... I am a non-technical person, help me connect' — repo created by asking. Arena (model-comparison) is teased for Day 2, alongside worktrees, Devin, and the Superplexity build against an existing codebase — 'from scratch everything looks hunky-dory; picking up existing code is where things break.'