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I reopened a file I had already fixed that morning. Not metaphorically. I literally re-fixed a bug I had closed four hours earlier, because between the fix and the reopen, my brain had quietly deleted the entire afternoon. That is the ADHD tax most productivity advice never names: it is not that you cannot focus, it is that the working model of what you were doing does not survive the gap between sessions. CLAUDE.md is the cheapest fix I have found for that specific failure. This is the companion to my Claude Code ADHD workflow ; that post is the full system, this one zooms all the way in on the single file doing most of the work. What Is CLAUDE.md, Actually? CLAUDE.md is a Markdown file that Claude Code reads automatically at the start of every session. You do not paste it. You do not remind Claude it exists. It just gets read, every time, before the first line of work. There are two places it lives: ./CLAUDE.md at a project root holds rules for that project: the tech stack, the conventions, the gotchas. ~/.claude/CLAUDE.md holds your global rules: things true across everything you build (your voice, your defaults, the things you never want re-litigated). For a neurotypical developer this is a convenience. For an ADHD developer it is a prosthetic. The difference is what the file is replacing. Why CLAUDE.md Is External Working Memory for ADHD Brains Working memory is the mental scratchpad that holds "what I am doing right now and the three things I just decided about it." ADHD shrinks that scratchpad and makes it leaky. Every interruption, a Slack ping, a stray thought, a context-switch to email, knocks items off it. When you return, the scratchpad is blank and you rebuild it from scratch. The American Psychological Association puts the rebuild cost at roughly 23 minutes per context switch for a typical brain. For an ADHD brain that involuntarily switches more often and rebuilds slower, the real cost is higher and it compounds. Ten switches a day is not ten minutes

At WWDC 2026, Apple introduced Xcode 27, which makes it easy to kick off tasks with coding agents, iterate on new project ideas, and customize the workspace. It also introduces DeviceHub for unified simulator and device management, along with enhancements to Organizer and Instruments, among many other improvements. By Sergio De Simone

Today, I’m talking with Adam Bry, who is CEO of Skydio, the leading US maker of autonomous drones. Before we recorded this episode, I actually got to remotely operate one of Skydio’s drones in the Bay Area from Adam’s laptop in our podcast studio in New York and fly an indoor drone around our office. […]

After failing 3 coding interviews, I realized the problem wasn't practice it was how I was practicing. I spent 6 months grinding LeetCode before my first FAANG interview. 400+ problems solved. Every "Blind 75" problem is memorized. I felt ready. Then the interviewer asked a sliding window variation I hadn't seen before. I froze. Drew a blank. Bombed the interview. The problem wasn't that I hadn't practiced enough. The problem was that I had practiced incorrectly. I memorized solutions instead of understanding patterns. I can recite code, but I struggle to adapt when problems change slightly. So I built something different. Introducing AlgoPatterns A pattern-first DSA learning platform with visualizations that actually show you how algorithms work. algopatterns.in What Makes It Different 1. Pattern-First, Not Problem-First Most platforms throw 2000+ problems at you and say, "Good Luck." AlgoPatterns organizes everything around 17 core patterns: Two Pointers Sliding Window Binary Search BFS/DFS Dynamic Programming Backtracking And 11 more... Master the patterns, and you can solve any variation. 2. Visualizations That Actually Help We have 50+ interactive visualizers that show algorithms step-by-step: Watch two pointers converge in real-time See the DP table fill cell by cell Trace BFS spreading level by level Visualize the call stack during recursion Reading code is one thing. Seeing it executed is completely different. 3. Curated, Not Overwhelming 315 hand-picked problems organized by pattern. Each problem includes: Company tags (Google, Amazon, Meta, etc.) Frequency indicators Pattern classification Difficulty rating No more random grinding. Practice the right problems in the right order. 4. Real Code Templates Every pattern comes with: Java templates (copy-paste ready) "When to use" indicators Common mistakes to avoid Key insights from each pattern Who It's For Interview preppers who want to learn patterns, not memorize solutions CS students who find textbook expla

La trahison du chiffre Vendredi 15 mai, 16 h 13. L'alerte Sentry remonte sur le téléphone. La première réinscrite Phase 1 attend devant l'écran de paiement, son nom est en haut de mon onglet. Je pose la canette, je rouvre l'écran. La tasse à tête de Françoise, sur le poste d'à côté, capte un reflet jaune que je remarque sans le regarder. La stack trace tient en plein écran. Le stack trace s'ouvre, neuf champs sur dix à null , et un chiffre que je n'ai pas vu venir. type = "StripeConnectionError" message = "An error occurred with our connection to Stripe." code = null statusCode = null requestId = null duration = 9 ms Neuf millisecondes. Sur une route Vercel en région Paris, un DNS résout en quarante millisecondes, un handshake TLS coûte cent à deux cents. Neuf millisecondes, ce n'est pas un appel réseau qui a échoué. C'est un appel réseau qui n'a jamais eu lieu. Le SDK n'est pas arrivé jusqu'à la fibre. L'instinct propose immédiatement trois patchs. Timeout serverless Vercel — j'ajoute maxDuration , je redéploie. Clé révoquée — je vais la rouler. Compte Stripe restreint après le passage en mode live — j'ouvre un ticket support. Ces trois hypothèses sont plausibles. Aucune des trois n'est falsifiable par le symptôme seul, et c'est précisément ce qui les rend dangereuses : chacune ouvre un cycle de quinze à trente minutes avec rollback à la fin si elle se trompe. Multiplié par trois, on tient une demi-journée perdue avec la cliente toujours en train de cliquer. Je n'ai pas le temps. Une réinscrite attend. Quatre tests, dans l'ordre Je connais la classe d'incident — « preview marche, prod casse » , ou son symétrique. La règle, pour cette classe, c'est qu'on ne corrige rien tant qu'on n'a pas discriminé les couches. Quatre tests, exécutés dans l'ordre. Chacun élimine une famille d'hypothèses, pas une hypothèse isolée. Et chacun est conçu pour réfuter ce qu'il vient interroger — parce qu'un test qui cherche à confirmer trouve toujours, par sélection, ce qu'il cherche. Te

The number that lied Friday May 15, 4:13 PM. The Sentry alert pings on my phone. The first Phase 1 re-enrolling student waits in front of the payment screen, her name at the top of my tab. I put down the can, I reopen the screen. The mug with Françoise's face on it, on the desk next door, catches a yellow reflection I notice without looking at. The stack trace fills the screen. The stack trace opens, nine fields out of ten at null , and a number I didn't see coming. type = "StripeConnectionError" message = "An error occurred with our connection to Stripe." code = null statusCode = null requestId = null duration = 9 ms Nine milliseconds. On a Vercel route in Paris region, DNS resolves in forty ms, a TLS handshake costs one to two hundred. Nine milliseconds isn't a network call that failed. It's a network call that never happened. The SDK didn't reach the wire. Instinct immediately offers three patches. Vercel serverless timeout — I add maxDuration , redeploy. Revoked key — I'll rotate it. Stripe account restricted after the live switch — I open a support ticket. These three hypotheses are plausible. None of the three is falsifiable from the symptom alone, and that's precisely what makes them dangerous: each opens a fifteen-to-thirty-minute cycle with rollback at the end if it's wrong. Multiplied by three, half a day lost with the customer still clicking. I don't have time. A student is waiting. Four tests, in order I know the incident class — "preview works, prod breaks" , or its mirror. The rule for this class is that you fix nothing until you've discriminated the layers. Four tests, executed in order. Each eliminates a family of hypotheses, not an isolated hypothesis. And each is designed to refute what it interrogates — because a test that seeks to confirm always finds, by selection, what it's looking for. Test 1 — reproduce in the witness environment. I rerun the same funnel in preview, with the sk_test_ key. Checkout opens in three hundred fourteen milliseconds,

HashiCorp has announced the general availability of the Terraform MCP Server, an open-source MCP server that enables agents to integrate with Terraform Registry APIs. The company says that it can improve infrastructure teams productivity by relieving engineers of rote tasks. By Sergio De Simone

本記事は、AtCoder Beginner Contest 462 (ABC462) に参加した際の、A〜E問題の復習と解答の備忘録です。コンテスト中に考えた解法の方針や、提出したPythonのコードについて整理しています。 A - Secret Numbers / 実行時間制限: 2 sec / メモリ制限: 1024 MiB / Difficulty: None 配点 : 100 点 問題文 英小文字と数字のみからなる文字列 $S$ が与えられます。 $S$ から数字である文字だけを取り出し、元の順序のまま並べた文字列を求めてください。 制約 $S$ は英小文字と数字のみからなる長さ 1 以上 50 以下の文字列 自分の解答の方針 一文字づつ数字かどうかを判定し、数字のみを配列に入れて出力する。 提出の時には数字かどうかの判定は0-9のどれかに含まれているかを調べたが、解説ではPythonは isdigit() で数値かどうかを調べられるらしい。 提出したコード S = list ( input ()) T = [] for i in range ( len ( S )): if S [ i ] in [ " 1 " , " 2 " , " 3 " , " 4 " , " 5 " , " 6 " , " 7 " , " 8 " , " 9 " , " 0 " ]: T . append ( S [ i ]) print ( "" . join ( T )) B - Gift / 実行時間制限: 2 sec / メモリ制限: 1024 MiB / Difficulty: None 配点 : 200 点 問題文 人 1 から人 $N$ の $N$ 人がギフトを送り合いました。 人 $i$ は人 $A_{i,1}, A_{i,2}, \dots, A_{i,K_i}$ の $K_i$ 人にギフトを送りました。 $i=1,2,\dots,N$ に対し、人 $i$ にギフトを送った人を全て求めてください。 制約 $2 \le N \le 100$ $1 \le K_i \le N-1$ $1 \le A_{i,1} < A_{i,2} < \dots < A_{i,K_i} \le N$ $A_{i,j} \neq i$ 入力される値は全て整数 自分の解答の方針 辞書に人 $i$ と、その人にギフトを送った人の番号をリストとして持つことを考える。 入力で受け取った、ギフトを送った人と送られた人すべてに対して辞書に登録し、結果を出力する。 提出したコード N = int ( input ()) dct = dict () for i in range ( N ): dct [ i + 1 ] = [] for i in range ( N ): A = list ( map ( int , input (). split ())) for j in range ( 1 , A [ 0 ] + 1 ): dct [ A [ j ]]. append ( i + 1 ) for i in range ( N ): print ( " " . join ([ str ( len ( dct [ i + 1 ]))] + list ( map ( str , dct [ i + 1 ])))) C - Not Covered Points / 実行時間制限: 2 sec / メモリ制限: 1024 MiB / Difficulty: None 配点 : 300 点 問題文 2 次元平面上に点 1 から点 $N$ の $N$ 個の点があります。点 $i$ $(1 \le i \le N)$ の座標は $(X_i, Y_i)$ です。ここで、 $X, Y$ はそれぞれ $(1,2,\dots,N)$ の順列であることが保証されます。 左下の頂点を $(0,0)$ 、右上の頂点を $(X_i, Y_i)$ とする $x$ 軸に平行な辺と $y$ 軸に平行な辺のみからなる長方形の内部（辺上を含まない）に点 1 から点 $N$ までの $N$ 個の点をどれも含まないような $i$ の個数を求めてください。 制約 $1 \le N \le 3 \times 10^5$ $1 \le X_i, Y_i \le N$ $X, Y$ はそれぞれ $(1,2,\dots,N)$ の順列 入力される値は全て整数 自分の解答の方針 端から考えたいので、初めに $X$ についてソートする。 $X$ が小さい順に見ていっ​​たとき、現在の点が作る長方形の内部にほかの点が含まれるかどうかは、、これまでに走査した（$X$座標が自身より小さい）点の中に、自身より $Y$ 座標

Every AI agent skill you write burns context on every turn. Not just when the skill is running. On every turn. The agent keeps each skill's name and description loaded permanently so it knows when to invoke them. A vague description is not just a documentation problem. It is a tax you pay per message, forever. That is the problem I built skillscore to catch. When addyosmani/agent-skills hit 52,000 stars and went to #1 trending on GitHub, I had my benchmark. 24 production-grade skills written by people who clearly know what they are doing. If a static linter has anything useful to say at this level, this is where to find out. So I ran it. One command. 24 skills. Two seconds. This is what skillscore 0.2.0 can do now: skillscore /path/to/agent-skills/ One command scores everything in the tree. Here is the output: Three skills from addyosmani/agent-skills scored in one command, then a drill-down into the lowest scorer. The full results Skill Score Grade spec-driven-development 91 A browser-testing-with-devtools 91 A deprecation-and-migration 91 A frontend-ui-engineering 91 A test-driven-development 88 B code-review-and-quality 88 B interview-me 86 B ci-cd-and-automation 85 B code-simplification 85 B context-engineering 85 B documentation-and-adrs 85 B incremental-implementation 85 B security-and-hardening 85 B shipping-and-launch 85 B source-driven-development 85 B using-agent-skills 85 B doubt-driven-development 80 B observability-and-instrumentation 80 B planning-and-task-breakdown 80 B api-and-interface-design 78 C debugging-and-error-recovery 77 C git-workflow-and-versioning 77 C idea-refine 77 C performance-optimization 77 C Average: 84/100 (B) To be clear: 84 across 24 production skills is excellent. No failures. No D grades. Most skill libraries I have tested do not get close to this. The instruction content inside these skills is genuinely good. What the linter found is at the edges, not in the core. Two gaps. Five skills. Every single C. I drilled into all five

AWS recently announced CDK Mixins, a new AWS CDK feature that lets developers add reusable capabilities like security, monitoring, and configuration to AWS resources. Mixins work across different construct types, making infrastructure code more flexible and reusable. By Renato Losio

Verdict: Quick verdict: Zapier wins on simplicity and breadth — 7,000+ integrations, no-code setup, great for non-technical users. Make (formerly Integromat) wins on power-per-dollar — complex multi-step workflows at a fraction of Zapier's price, with a visual canvas that's genuinely better for complex logic. n8n wins if you're technical and willing to self-host — unlimited workflows, unlimited runs, zero ongoing cost after setup. For most small businesses: Make. For enterprises with non-technical teams: Zapier. For technical founders or developers: n8n. The automation tool market matured a lot between 2022 and 2026. Zapier, once the clear leader, is now meaningfully more expensive than its competitors — and Make and n8n have closed most of the feature gaps. If you're still paying Zapier prices without re-evaluating, you're almost certainly paying 3-5x what you need to. This comparison covers all three tools honestly, including their limits — because the right choice depends heavily on your technical comfort level and workflow complexity. The three tools at a glance Factor Zapier Make n8n (cloud) Free tier 100 tasks/month, 5 Zaps 1,000 ops/month, unlimited scenarios 2,500 steps/month, unlimited workflows Paid starts at $19.99/month (750 tasks) $9/month (10,000 ops) $20/month (10,000 steps) Native integrations 7,000+ 1,500+ 400+ (plus HTTP for anything) Visual workflow editor Linear, simple Canvas, branching Node-based, very flexible AI integration Yes (AI actions) Yes (AI modules) Yes (LangChain, OpenAI, etc.) Self-hosted option No No Yes (free, unlimited) Learning curve Low Medium High (developer-focused) Zapier — the everything-just-works option Zapier's advantage is breadth and simplicity. 7,000+ apps (essentially anything with an API), a straightforward "trigger → action" model, and enough guardrails that non-technical users rarely get stuck. If you need to connect Salesforce to Slack to Google Sheets without touching any code, Zapier is the fastest path from id

You're about to install a VS Code extension. Maybe it's a formatter, a linter, a theme, an AI tool....

TL;DR - Getting an app to run is now the easy part. AI is very good at producing something that...

https://dsa-life-simulator-frontend.vercel.app"I made a free tool to make DSA practice feel like an RPG — would like feedback from this community"Been grinding DSA for months and it never felt fun. So I built something. What it does: 🏟️ Real-time 1v1 Arena battles against other devs 🧪 Lab to create and publish your own challenges 🏘️ Community Hub to attempt others' challenges 📖 AI writes your weekly coding journey as a life story 🎮 XP, credits, levels, leaderboards Stack: React + Tailwind + Firebase + Node.js + Socket.IO + Groq AI Still early — would genuinely love feedback from people who've felt the pain of traditional DSA prep.

GitHub moved Copilot Chat's richer pull request experience to general availability this week — side-by-side chat with diffs, inline editing, and context-aware answers without leaving the review view. Previously in public preview, it is now live for all Copilot license holders. It is a real improvement for reviewing changes inside a single pull request. But it highlights a gap that per-PR AI tooling structurally cannot close: knowing what is open across the rest of your organisation. The Problem That Lives Outside the PR Most engineering teams don't work in one repository. They ship across services, libraries, and infrastructure — often with related PRs open in multiple repos simultaneously. A reviewer approving a payments service change without knowing that a dependent auth-service PR is still in draft is reviewing without full context. This is not a quality-of-feedback problem. It is a visibility problem. No amount of intelligence surfaced inside a PR tells you what is happening across your repositories. Gartner's 2026 assessment of AI coding agents makes the point clearly: the bottleneck has shifted from generating code to reviewing, securing, and governing it. Better per-PR AI raises the floor on feedback quality. The teams that pull ahead will be the ones who also solve the coordination layer — which PRs are open, which are stale, which are blocked on a dependency in another repo. What Changes With Better In-PR AI GitHub's GA release makes the review experience faster and less disruptive for individual PRs. That matters. But as per-PR intelligence becomes table stakes, the differentiator shifts toward cross-repo awareness: who is waiting for review, what related work is in flight, and where the actual bottlenecks in the delivery pipeline are. Engineering leaders should be watching PR age distribution and review load across all repositories — not just the ones that happen to be open in a browser tab right now. For teams already dealing with multi-repo sprawl, Cod

Part 7 of 7 · Series: Building Your AI Developer Handbook · GitHub The Scenario You're building a password reset feature. User enters email → gets a reset link → clicks link → enters new password. Standard flow. Medium complexity. Let's walk through every step using the full workflow — as if you're looking over the shoulder of someone who built this system. "Show me your workflow and I'll show you your output quality." Before You Even Type Claude loads automatically in the background: ✓ ~/.claude/CLAUDE.md loaded ← the global handbook ✓ .claude/CLAUDE.md loaded ← project rules (TypeScript, pnpm) ✓ memory/MEMORY.md scanned ← all lessons and preferences You haven't typed anything yet. Claude already knows: Feature-based folder structure State management ladder No mocking the database No AI attribution in commits No useCallback without profiler evidence "A doctor who reviews your file before you enter the room is more useful than one who asks 'so, remind me who you are?'" Step 1: /status — Confirm the Setup /status Model: claude-sonnet-4-6 Effort: normal Plugins: security-guidance ✓ Thirty seconds. Sometimes the wrong model loads due to overload fallback. Sometimes a plugin fails silently. This check costs 30 seconds and prevents a surprise 30 minutes later. "A pilot's first action after sitting in the cockpit isn't to take off. It's to check all instruments are reading correctly." Step 2: /cost — Baseline /cost → Tokens used: 2,847 | Estimated cost: $ 0.004 Note this number. You'll compare it later before the expensive code review step. A surprise spike means something went wrong. Step 3: /plan — Design Before Coding /plan Build a password reset feature: - User enters email on /forgot-password - System sends a reset link (token, expires in 1 hour) - User clicks link → /reset-password?token=xxx - User enters new password - Token validated, password updated, token invalidated Claude responds with a plan — no code yet : Proposed approach: 1. DB: Add password_reset_tokens

Uber's CTO told the world this month that the company spent its entire 2026 AI allocation by April. The story has been reported in a handful of outlets, hit the front page of Hacker News for 397 points and 469 comments , and is mostly being read as a cost-of-AI-tools story. It is one. It is also, on a closer reading of the numbers, a pricing-model story — and the structural fact that almost none of the coverage has emphasized is the one that determines whether this is a one-company anomaly or the beginning of an industry-wide budgetary crisis. The structural fact is that Claude Code, like most enterprise AI tooling in 2026, is priced on token consumption, not per-seat licensing. Token-based pricing scales with how aggressively the tool is used. Per-seat enterprise SaaS pricing — the model corporate IT budgets are built around — scales with how many people have access to it. Those two cost curves diverge in exactly the territory where productivity tools are designed to operate: high-engagement, daily-use, gradually-deepening workflows. The Uber data is the first public-facing version of a math problem most enterprise IT departments are about to discover privately. The numbers Uber CTO Praveen Neppalli Naga , named in Yahoo Finance's and Benzinga's coverage, said publicly that Uber is "back to the drawing board" on AI budgeting after the surge in Claude Code use blew through internal projections. The specific numbers, as reported across the multiple outlets covering the story: Claude Code adoption inside Uber's ~5,000-engineer organization went from 32% to 84% over four months. 70% of committed code at Uber is now AI-originated. 11% of live backend updates are "being written by AI agents built primarily with Claude Code," per the reporting. Per-engineer monthly API costs: $500 to $2,000. Uber's annual R&D spend is around $3.4 billion , of which the AI tooling line was a much larger fraction than expected. Cursor adoption plateaued; Claude Code dominated. These are ext

What Is a Claude Code Configuration File? A Claude Code configuration file is a structured file — either CLAUDE.md (a Markdown document) or settings.json (a JSON schema file) — that controls how the Claude Code AI coding assistant behaves within a project or organization. These files define the agent's permissions, memory context, tool access, allowed shell commands, and behavioral guardrails. Without them, Claude Code operates with broad defaults that may not align with your security posture or project conventions. Claude Code reads configuration from multiple locations in a defined hierarchy: a global user-level ~/.claude/settings.json , a project-level .claude/settings.json at the repo root, and one or more CLAUDE.md files that can be nested in subdirectories. The agent merges these at startup, with project-level settings taking precedence over global ones. Understanding that hierarchy isn't optional — it's the foundation of any serious deployment. Why Claude Code Configuration Files Matter in 2026 Claude Code has moved from a tool used by individual engineers to something teams are deploying org-wide, running in CI/CD pipelines, and integrating with production infrastructure. That shift changes the risk profile completely. A misconfigured agent with shell access and no guardrails isn't a productivity tool anymore — it's a liability. Anthropic's own documentation on Claude Code security acknowledges that the agent can execute terminal commands, read and write files, and make network requests. By default, many of these capabilities require per-operation approval, but configuration files can silently expand those permissions across an entire organization if applied at the global or enterprise policy layer. The CISA and NSA joint guidance on AI-assisted development tools (published in late 2024) specifically flagged AI coding assistants as a new attack surface for supply chain compromise — the concern being that an agent with write access to source files and no beha

Problem Link - https://leetcode.com/problems/delete-node-in-a-linked-list/ This is one of those interview questions that looks impossible at first. Normally, to delete a node from a Linked List, we need access to the previous node. But in this problem, we're only given the node that needs to be deleted. No head. No previous pointer. So how do we remove it? Let's understand the trick. Problem Statement Write a function to delete a node in a singly linked list. You are not given the head of the list. Instead, you are given only the node that needs to be deleted. Example Input: 4 -> 5 -> 1 -> 9 node = 5 Output: 4 -> 1 -> 9 Initial Thought Normally we delete a node like this: prev.next = node.next But here: We don't have prev We don't have head So the usual deletion approach is impossible. Key Observation Although we cannot delete the current node directly, we can make it look like it never existed. Consider: 4 -> 5 -> 1 -> 9 We need to delete: 5 Instead of removing node 5 , copy the value of the next node into it. 4 -> 1 -> 1 -> 9 Now remove the next node. 4 -> 1 -> 9 The original value 5 has disappeared. Mission accomplished. Intuition Copy the next node's value into the current node. Skip the next node. The current node now behaves as if it was deleted. Since the problem guarantees that the given node is not the tail node, a next node will always exist. Dry Run Input 4 -> 5 -> 1 -> 9 node = 5 Current node: 5 Next node: 1 Step 1 Copy next node value. node.val = node.next.val List becomes: 4 -> 1 -> 1 -> 9 Step 2 Skip next node. node.next = node.next.next List becomes: 4 -> 1 -> 9 Done. Optimal Java Solution class Solution { public void deleteNode ( ListNode node ) { ListNode cur = node . next ; node . val = cur . val ; node . next = cur . next ; } } Even Shorter Version class Solution { public void deleteNode ( ListNode node ) { node . val = node . next . val ; node . next = node . next . next ; } } Complexity Analysis Metric Complexity Time Complexity O(1) Space Comp

Note: This is an English digest of the original Zenn post (Japanese) . Read there for the full timeline and commit-level trace. TL;DR We ship tasteck , a B2B SaaS for the Japanese night-leisure industry (dispatch + cast shift management). 8 years of operational data, ~100 venues live. Two days after the MCP design post , ChatGPT Plus can call our tools live: "Who's available tonight?" → MCP list_available_drivers → JSON → natural-language reply. Estimated B2 OAuth sprint = 2 weeks (6/16–7/1). Actual = 1 day , by reading the spec carefully before touching code. We hit 12 distinct traps between "OAuth issuance works" and "ChatGPT actually invokes the tool." The QA logs caught every one. What we shipped 3 read tools (B1): list_available_drivers — drivers free tonight list_cast_shifts — today's cast shift roster list_assignable_casts — joined resolution: roster ∧ stage-name set ∧ shop match Natural-language date helper: resolveBusinessDate(naturalText, company) — handles "today / tomorrow / day-after-tomorrow" and the per-tenant business-day boundary (e.g. day flips at 04:00 or 05:00, configured per Company.changeDateTime ). MCP SDK Server + SSE transport: @modelcontextprotocol/sdk wired into a NestJS controller. One SSE connection = one McpServer instance, company-scoped, with a session_id Map routing POST /messages . OAuth flow (B2, finished in one day across 7 steps) Step What Commit 1 Protected Resource Metadata endpoint (RFC 9728) d6f05ff6 2 /authorize + consent screen + PKCE start 107edbcb 3 /token + PKCE verify + JWT issue + resource (RFC 8707) ffd0468c 4 OAuthAccessTokenGuard (RS256 + HS256 fallback, extracts companyId / staffId ) f2c9bed4 5 Streamable HTTP transport (SSE → POST /sse/:companyId for JSON-RPC) 3a28d92f 6 resolveBusinessDate undefined fallback (`(naturalText 7 QA redeploy + ChatGPT live demo — The 12 traps (compressed) The full timeline is in the Japanese post; the abridged list: Discovery path mismatch. ChatGPT expected {% raw %} .well-known/oauth