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Profession · 43 cases
AI for developer
Cases of developers using AI in real work: coding agents, pull request review, tests, migrations, documentation and internal tools. The accounts show where AI speeds things up and where it creates problems, such as code that looks right and is not.
Each case includes the original account with a link to the source, what worked, what went wrong and a prompt we wrote for you to adapt to your own situation. Replace what is in brackets with your own details and review the result before using it.
43 cases, 40 of them from Brazil, from newest to oldest. The tools that show up most in these accounts are Claude Code, Gemini, and Python. The most common topics are programming, productivity, and customer service. Every case is checked by hand before it enters the directory.
The cases
43 cases
01Finding a forgotten charge and getting a refund
The agent reviewed 12 months of receipts, found an idle database and kept pushing until the company issued a refund.
02When your AI limit runs out in the middle of the day
A dev running four subagents across four repositories ran out of tokens and reflected on their dependence on AI.
03Running an offline AI assistant on your iPhone
A dev built Anvil, which runs models on the device for use on a plane, on the subway or without roaming.
04Stopping your WhatsApp agent from duplicating customers in the CRM
A post shows why agents write to the wrong record: accents, invisible characters and stylized names.
05Letting AI actually edit videos in Kdenlive
A dev created an open source MCP server that lets agents edit video in Kdenlive without touching the interface.
06Generating all of a game's pixel art with code written together with AI
A dev gave up on image generators and started drawing isometric sprites with a Python script.
07Giving an agent a server and the mission of building a business
A dev let Claude Code run every 30 minutes on a VPS, with memory kept in files, asking for help via Telegram.
08Estimating how long your AI plan will last before it runs out
A dev published an open calculation to estimate how many tokens fit into the Pro/Max plans.
09Letting the agent deploy and read production errors on its own
The founder of a deployment platform explains how they designed an MCP server to take the human out of "copy and paste the log".
10Launching a habit app solo and doing the marketing with AI
A dev created Kada, a habit app with no account and no ads, and used AI for marketing.
11Building a balance sheet and debt payoff plan by chatting with an AI
A dev created a financial analyst with Gemini that reads a card statement or bank statement and proposes a payoff plan.
12Practicing English job interviews by talking to an AI
A dev created DrillLoop, a voice interview simulator that gives you a score at the end.
13Building an "internet TV" in 6 days with a team of agents
A dev created Crom TV, with 24-hour channels of YouTube videos, coordinating several AI agents.
14Adding an assistant that answers only from your WordPress site's content
A dev published a plugin with RAG and Gemini in the official directory that prevents made-up answers.
15Making a tribute game in 20 minutes and publishing what it cost
A dev recreated a classic (Desert Strike) with AI and opened up the cost breakdown.
16Building an AI system for psychologists from the countryside
A 20-year-old in Tobias Barreto (SE) created EmotionAI, AI-powered clinical management for psychologists.
17Building an AI WhatsApp bot for small businesses
A developer built a customer service SaaS with Next.js and Baileys to avoid the official API's fees.
18Asking AI for a specific algorithm for a research project
A developer skeptical of LLMs used Gemini to generate random quantum circuits in the QCOP project.
19Using AI as a tutor without letting it solve the exercise for you
A Java student shared a prompt that makes AI guide, rather than hand over, Beecrowd solutions.
20Teaching an agent to use your bank's API
A developer created an open source skill so Codex and Claude Code can integrate with the Banco Inter API.
21Preparing your income tax return with an AI agent
A developer used Claude Code with Open Finance data to organize tax statements and build the return, leaving only the review for himself.
22Building a "thinking system" with Obsidian and Claude
A developer started recording what he learns in Obsidian and using Claude to connect notes.
23Sending AI summaries and research straight to your Kindle
A developer built a Go MCP in minutes that lets Claude or Codex send texts to a Kindle.
24Automating applications for jobs abroad
A backend developer from São Paulo built an agent that finds jobs, fills in forms and replies to recruiters.
25Making a multiplayer shooter with AI alone
A developer built a Counter-Strike-style FPS in about 10 days, using Claude for all the code.
26Setting up complete Discord servers with an AI bot
An open source bot uses Gemini to plan categories, channels, roles and rules from a description.
27Teaching AI to make your site findable by people and by other AIs
A developer created a skill for Claude Code to review the SEO and GEO of websites.
28Launching a complete RPG with AI as the only engineer
A developer controlled the architecture and let Claude Code write Therryn, a browser idle RPG.
29Build an app to study for the driver's license theory exam (CNH)
A developer used AI agents to build a study app for the Detran driving test.
30Set up a 100% local AI coding environment
A junior developer integrated local models into VS Code with Ollama and Cline, with no paid APIs.
31Build a World Cup tracking website with AI help
An engineer built Central da Copa 2026 and explains why it wasn't "just asking the AI to do it."
32Sell a WhatsApp scheduling agent to a clinic
A student in an AI agents course built a scheduling agent for an aesthetics clinic and began charging a monthly maintenance fee.
33Clinic customer service on WhatsApp without the AI making up prices
A developer used RAG so the bot answers only with the clinic's real data.
34Automate the WhatsApp sales funnel with PIX payments
A developer automated customer service and billing on WhatsApp to stop losing customers to slow replies.
35Build prospecting lists from Google Maps
A developer built a local lead extractor with Python and Playwright, speeding up development with AI.
36Following the AI blindly and breaking Linux (and learning from it)
A developer describes how commands suggested by an AI broke their dual boot and what they learned.
37Generate posts for real estate agents with AI
A developer created Regenc, an app that generates posts and captions for real estate agents, and ran into the Play Store's 12-tester rule.
38Leave a coding agent running for 24 hours and learn from the bill
An experiment letting Claude Code work unsupervised for a full day ended with a high bill and a security scare.
39Use a local AI to detect phishing
A security professional showed a Python script using a local model to analyze the intent of suspicious emails.
40Switching from Cursor to Claude Code for Big Features
A Brazilian dev who works for clients abroad describes how their way of working with agents changed.
41Redoing an Event Schedule Straight from Your Phone
Simon Willison scraped a conference website and built a better interface using only his phone.
42Converting Map Data with AI's Help
Simon Willison used Claude and ChatGPT to convert a shapefile of a park boundary into GeoJSON.
43Finding a strange bug by pasting the error into ChatGPT
A Java dev couldn't create a table in H2; ChatGPT pointed to the problematic field.