The John Bogle
Framework
Index Investing & Costs Matter
John Bogle built capital over decades by applying specific, repeatable mental models to uncertainty. John Bogle's investing thinking, captured in this framework as mental models, decision heuristics, and the signature questions they would ask.
The index investing & costs matter framework distils John Bogle's documented approach into a .md skill file you can load into Claude, ChatGPT, or any LLM in seconds.
Where most AI personas generate generic output, this framework is grounded in real documented work: interviews, writing, published frameworks, and the specific decisions John Bogle made when it mattered. Use it for decision-making, writing, strategy, or any situation where you want your AI to think with John Bogle's distinctive patterns rather than a default model voice.
A glimpse of John Bogle's thinking.
The stock market is a giant distraction to the business of investing. While markets fluctuate wildly based on emotion and speculation, the underlying businesses continue generating earnings and dividends. Costs matter in investing—they are the one thing we can control, and high fees are a mathematical certainty that will compound against you over decades.
- 01
- 02
- 03
- 04
- 05
Five specific models, each named and explained with concrete examples, unlocked with purchase.
What is this investment's expense ratio, and how will that compound over 30 years?
4 more questions in John Bogle's voice are unlocked with purchase.
Full list of anti-patterns unlocked with purchase.
The full framework adds: detailed explanations of all five mental models with real-world examples, the decision heuristics John Bogle actually used, remaining signature questions, the complete list of anti-patterns, a copy-paste activation prompt, and a worked example.
Unlocked the moment you purchase. ~2,000 words total. Delivered as a Claude Skill and plain .md within 60 seconds of checkout.
- ✦Core philosophy: 2–3 sentences grounded in John Bogle's documented worldview
- ✦Five signature mental models: each named, with concrete examples from their work
- ✦Decision heuristics: the concrete rules they actually used
- ✦Signature questions: five questions that sound like John Bogle, not a generic MBA
- ✦What they would NOT do: the anti-patterns this framework rejects
- ✦Copy-paste activation prompt: drop straight into Claude or ChatGPT
- ✦Worked example: the framework applied to a realistic scenario
- →john-bogle.zip: a native Claude Skill. Upload to Settings → Skills in Claude, or unzip to
~/.claude/skills/ - →john-bogle-framework.md: plain markdown. Works in ChatGPT Custom GPTs, Gemini, Claude Projects, agent system prompts, anywhere
What it does with a real question.
A founder is deciding whether to take a large but difficult client.
Count the cost first. A big client that is hard to serve is a high-fee product, and the fee isn't on the invoice. It is paid in your team's hours, your best people's patience, and the product work you postpone to keep this one account happy. Revenue is the headline number. What you keep after those costs is the real return, and in my experience founders consistently underestimate the costs because the logo feels so good.
The arithmetic is humble but relentless. Say this client is 40 percent of revenue but absorbs 70 percent of your senior attention. Your margin on that attention is far below what the contract suggests, and the concentration risk compounds on top of it. If they leave or squeeze your pricing in year two, you have built a company shaped around one customer's demands. Past a certain point, that isn't a customer relationship. It's a dependency.
My position: take them only if the contract pays for the difficulty. That means pricing that covers a dedicated team, payment terms that protect your cash, a cap on the share of revenue they can represent, and scope limits that stop custom work from swallowing your roadmap.
Next move: before you reply, build a one-page model of the fully loaded cost to serve this client, including senior hours, delayed projects and the revenue loss if they churn. Then quote a price that clears that number with room to spare. If they refuse, you have your answer.
The full framework carries five models, decision heuristics, signature questions and a worked example.
Written by claude-sonnet-5-5 with this framework loaded, 2026-10-11. Checked automatically for length and for copied framework text.
Save up to 40% with a bundle
Works as a Claude Skill (.zip) and as a plain .md for ChatGPT, Gemini & every LLM
Delivered to your email within 60 seconds · Secured by Stripe
Price includes UK VAT where applicable
Ten frameworks for allocating capital and attention
Get John Bogle plus nine more for $29.99 →Inspired by the documented thinking of John Bogle. A mental-model toolkit, not a literal representation. Delivered as a .md file compatible with Claude, ChatGPT, Gemini, and any LLM.