# Claude Fable 5.1: Not Just Code. It Made Me A Film, 7 Sheets And 13 Slides.

## Executive summary

This review analyzes Claude Fable 5.1's performance in 'knowledge work,' demonstrating that the model excels at generating complex first drafts (e.g., financial models and decks) even on low-effort settings. The speaker emphasizes that while low effort is ideal for rapid iteration and initial concepts, increasing the effort level provides deeper due diligence, surfacing critical questions and improving verifiability. Fable 5.1 was shown to handle diverse tasks—from building a Discounted Cash Flow (DCF) model in Excel to generating a cinematic architectural walkthrough using Blender code.

## Key takeaways

- Low Effort for First Drafts: Running Fable 5.1 on the low-effort setting successfully generated a seven-sheet workbook and a 13-slide deck for a complex acquisition scenario (GoPro/Starman), proving its utility for initial, meaningful drafts with minimal token cost.
- Effort Levels Define Depth: Increasing the effort level from low to extra significantly enhances the output by adding advanced financial elements (e.g., Weighted Average Cost of Capital - WACC), explicit funding needs, and linking multiple sources, providing a sense of 'supercomplete thinking.'
- Versatility Across Media: Fable 5.1 demonstrated capability across different knowledge work types: generating financial models (Excel/PowerPoint), writing concise articles (Toyota case study), and creating a full 37-second architectural video walkthrough using Blender code.

## Technical details

- Knowledge Work Definition: The speaker defines knowledge work as an 'extremely messy process' that is difficult to verify or define as 'done,' contrasting it with deterministic tasks like code compilation.
- Financial Modeling (DCF): The model was tasked with researching a transaction and building a post-acquisition Discounted Cash Flow (DCF) model in Excel, which successfully calculated valuation scenarios ($1.15/share base case). The extra effort setting improved this by adding explicit deal probabilities and WACC calculations.
- Token Efficiency & Cost: Fable 5.1 is highlighted for its token efficiency on the low setting, allowing users to get substantial output without consuming excessive tokens compared to previous versions (e.g., Fable 5). The speaker notes that while Fable 5.1 is more expensive than Opus 5, its efficiency makes it valuable for iterative knowledge work.

## Practical implications

- Use low-effort settings for rapid prototyping and generating initial drafts of complex documents (spreadsheets, decks).
- Treat the AI output as a strong first draft that requires human review, especially regarding source verification and assumption checking.
- Leverage high-effort settings when deep due diligence or finding non-obvious questions is critical to the investment decision.
- The model's ability to generate code for visual media (Blender) suggests potential use in rapid concept visualization for client pitches.

## Topics

AI Model Evaluation, Knowledge Work Automation, Financial Modeling, Generative AI Video, Token Economics, Claude Fable 5.1 Review, Nate's Newsletter (Substack)

Source: https://www.youtube.com/watch?v=55rDzRkUVdE