Andrej Karpathy: "90% of your AI coding bill is paying for context you didn't need to send"
Here are 10 things senior AI engineers stopped wasting tokens on:
1. Auto-context loading 50 files for a 30-line fix: $1.20/turn for tokens you'll never read. 80% input waste, every session
2. Running Opus on lint, format, and rename tasks: $0.60 for what Haiku nails at $0.02. 30x overpay on the cleanup tier
3. Tool call loops that re-send the full repo on every retry: 5x context cost per agentic flow. fixing these alone cuts 30-50% of bills
4. Sonnet as the default model: Kimi 2.6 matches its quality on most coding tasks at 1/6 the cost. defaulting to Sonnet in 2026 is leaving 60-70% on the table
5. Streaming responses on stable-prefix workflows: kills your prompt cache. you pay 10x for tokens that should have cost cents
6. "Just in case" file includes: 80,000-token prompts that should be 3,000. context bloat is the silent budget killer
7. Per-session knowledge rebuilding: 10 min writing a SKILL.md once vs paying agents to re-figure out your environment every run. $4 vs $0.30 per execution
8. Single-model setups: premium tier on every task is the most expensive mistake in AI coding right now
9. Asking 10 small questions one at a time: 10 separate input prefix charges vs one batched call. 70-90% savings on routine workflows
10. Buying Claude Pro + ChatGPT Plus + Cursor Pro: you seriously use one. the other two are habit, not utility
what actually compounds instead:
- context discipline (grep before fetching, always)
- prompt caching on every stable prefix
- multi-model routing (Kimi 2.6 default, Opus for the 10%)
- graduated skills via SKILL.md files
- profiling tool calls before optimizing prompts
- the routing mindset (right model for right task)
in 12 months, the gap between developers shipping on $200/month and $4,000/month budgets won't be skill
it'll be how well they route
study this.
Imagine every pixel on your screen, streamed live directly from a model. No HTML, no layout engine, no code. Just exactly what you want to see.
@eddiejiao_obj, @drewocarr and I built a prototype to see how this could actually work, and set out to make it real. We're calling it Flipbook. (1/5)
🚨BREAKING: The historian who sold 50 million books told Davos that AI is no longer a tool.
Yuval Noah Harari: "AI is a knife that can decide by itself whether to cut salad or to commit murder."
His warning: AI will outcompete humans in everything built on language.
Laws. Books. Religion. Finance. All of it.
His "Agent vs Tool" distinction is the most important mental model for understanding AI that 99% of people are ignoring.
Here are 9 Claude prompts built on Harari's framework that make AI think like an agent, not a parrot:
Someone built an open-source engine that runs 500 AI agents with different personalities to debate any news story in real time.
They post, argue, and change each other's minds. Hour by hour. On your laptop.
⚠️ Warning/Reminder! ⚠️ #april1
Tomorrow is April Fools’ Day and so here are 10 timely ways to prepare so you do not get tricked.
🎯 Method 1:
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