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Every resource founders actually use, in one library.

The essays, videos, podcasts, books and tools behind every answer across eChai's hubs, from starting up to go-to-market, D2C, founder money and AI, each with a note on why it is here.

What founders use most, ranked by how many answers lean on it.

  1. A quick no-code vs code triage before you commit a weekend. easyclaw.com Article · How Founders Use AI How to Build AI Agents: 5 Best Platforms EasyClaw
  2. Names the paradox every founder hits: cheaper tokens, bigger bills. navyaai.com Article · How Founders Use AI AI Token Cost Over Time: Down 99.7%, Bills Up 3x NavyaAI
  3. Explains the quadratic context growth that quietly multiplies agent costs. leanopstech.com Article · How Founders Use AI AI Agents Burn 50x More Tokens Than Chats LeanOps
  4. How large buyers model agent economics, useful when selling to them. ey.com Article · How Founders Use AI Agentic AI Enterprise Token Cost EY
  5. Concrete per-task cost ranges from cheap chatbot turns to $5+ agent runs. cowork.ink Article · How Founders Use AI AI Agent Cost: Token Economics & Optimization Guide Cowork
  6. Walks through the exact math of an agent whose unit economics collapse. medium.com Article · How Founders Use AI Token Cost Trap: Why Your AI Agent's ROI Breaks at Scale Klaus Hofenbitzer
  7. One page comparing how each provider's caching discount actually works. prompthub.us Guide · How Founders Use AI Prompt Caching with OpenAI, Anthropic, and Google Models PromptHub
  8. Shows 72% of production cost sits outside the model invoice. optimumpartners.com Article · How Founders Use AI AI Token Costs: Why Enterprise AI Bills Keep Rising Optimum Partners
  9. A hands-on implementation guide with before-and-after cost numbers. digitalocean.com Guide · How Founders Use AI Prompt Caching for Anthropic and OpenAI Models DigitalOcean
  10. Saves you from the premature self-host-a-model cost trap. ml6.eu Article · How Founders Use AI Why 'Cheaper Tokens' Isn't a Good Reason to Own Your LLMs ML6
  11. Why the price curve should keep falling, and what that means for your roadmap. weightythoughts.com Article · How Founders Use AI AI's Plummeting Prices Are a Software Story, Not a Hardware One Weighty Thoughts
  12. The clearest official explanation of what an agent eval actually is. anthropic.com Guide · How Founders Use AI Demystifying evals for AI agents Anthropic
  13. The philosophy behind the top-grossing evals course, free to read. hamelhusain.substack.com Article · How Founders Use AI AI Evals For Engineers & Product Managers Hamel Husain
  14. The 60-second version of why evals became the must-have skill. x.com Thread · How Founders Use AI Lenny on evals: watch them build one live Lenny Rachitsky
  15. Written notes of the full workflow: error analysis to automated judges. aakashg.com Guide · How Founders Use AI AI Evals Step-by-Step: Hamel & Shreya Masterclass Aakash Gupta
  16. Explains pass@k and why you must run agent tests many times. cameronrwolfe.substack.com Article · How Founders Use AI Agent Evaluation: A Detailed Guide Cameron Wolfe
  17. Field lessons from teams that moved agents from demo to production. infoq.com Article · How Founders Use AI Evaluating AI Agents in Practice: Benchmarks, Frameworks, and Lessons Learned InfoQ
  18. A single-sitting starter recipe for your first agent eval. zenvanriel.com Guide · How Founders Use AI AI Agent Evaluation: A Practical Step-by-Step Guide Zen van Riel
  19. Covers the metrics that matter: task success, step count, faithfulness. turingcollege.com Guide · How Founders Use AI Evaluating AI Agents: A Practical Guide Turing College
  20. Connects evals to shipping cadence rather than treating them as QA theatre. lennysnewsletter.com Article · How Founders Use AI Building eval systems that improve your AI product Lenny's Newsletter
  21. A worked example you can copy line by line for your own product. arize.com Article · How Founders Use AI AI Evals Course Homework: the Recipe Bot Workflow Arize AI
  22. Surveys the tooling landscape so you do not build eval infrastructure from scratch. medium.com Article · How Founders Use AI AI Agent Evaluation: Frameworks, Strategies, and Best Practices Dave Davies
  23. A checklist to run before you let an agent near customers. getmaxim.ai Article · How Founders Use AI 10 Essential Steps for Evaluating the Reliability of AI Agents Maxim AI
  24. The same argument in shareable form for your team channel. simonw.substack.com Article · How Founders Use AI The lethal trifecta (newsletter edition) Simon Willison

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The hubs

Starting Up Find an idea, validate it, build, and land your first customers. 1046 questions GTM Go-to-market, from breaking in to how the best teams do it. 352 questions D2C Building a direct-to-consumer brand, India-first. 482 questions Wealth Paying yourself, ESOPs, secondaries, and de-risking founder wealth. 154 questions How Founders Use AI How founders actually put AI to work, mapped topic by topic. 278 questions Glossary Plain-language definitions of the startup and VC terms you'll hit. 390 terms
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