Split reverse engineering across three Claude models
A reversing setup where Sonnet 5.5 maps the binary, Opus 5.5 rebuilds the hard logic and Fable 5.1 only steps in to stress-test a theory that already passed its tests.
Source
@kaijucode on X · 2026-10-17
Written in our own words. Credit to the original author. Link checked 2026-10-17.
What they did
A reversing setup where Sonnet 5.5 maps the binary, Opus 5.5 rebuilds the hard logic and Fable 5.1 only steps in to stress-test a theory that already passed its tests.
Result (as claimed)
47 likes on X.
Tools they used
Cost: Claude Sonnet 5.5: from $2 in / $10 out per 1M tokens; Claude Opus 5.5: from $4 in / $20 out per 1M tokens; Claude Fable 5.1: from $10 in / $50 out per 1M tokens.
Set it up
Pick a contained repo or task
Start on a branch or side project where mistakes are cheap.
Install and configure
Set up Claude Sonnet 5.5, Claude Opus 5.5, Claude Fable 5.1. Read what it can run on your machine and limit permissions where possible.
Run it on a real task
Give it a well-scoped issue and let it work. Review the diff like any pull request.
Add guardrails
Keep tests and CI in the loop, and never let an agent push to main or touch production secrets unattended.
Copy the full setup prompt
Paste into your agent and it will walk you through the setup, asking before anything that sends, posts or spends.
You are helping me set up this AI use case end to end in Claude Code. Goal: Split reverse engineering across three Claude models What the original author did: A reversing setup where Sonnet 5.5 maps the binary, Opus 5.5 rebuilds the hard logic and Fable 5.1 only steps in to stress-test a theory that already passed its tests. Reported result (as claimed by the author): 47 likes on X. Source: https://x.com/kaijucode/status/2111445731823509688 Tools they used: Claude Sonnet 5.5, Claude Opus 5.5, Claude Fable 5.1 Category: Dev & ops Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
You are helping me set up this AI use case end to end in Codex. Goal: Split reverse engineering across three Claude models What the original author did: A reversing setup where Sonnet 5.5 maps the binary, Opus 5.5 rebuilds the hard logic and Fable 5.1 only steps in to stress-test a theory that already passed its tests. Reported result (as claimed by the author): 47 likes on X. Source: https://x.com/kaijucode/status/2111445731823509688 Tools they used: Claude Sonnet 5.5, Claude Opus 5.5, Claude Fable 5.1 Category: Dev & ops Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
You are helping me set up this AI use case end to end in Grok Bot. Goal: Split reverse engineering across three Claude models What the original author did: A reversing setup where Sonnet 5.5 maps the binary, Opus 5.5 rebuilds the hard logic and Fable 5.1 only steps in to stress-test a theory that already passed its tests. Reported result (as claimed by the author): 47 likes on X. Source: https://x.com/kaijucode/status/2111445731823509688 Tools they used: Claude Sonnet 5.5, Claude Opus 5.5, Claude Fable 5.1 Category: Dev & ops Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
The Daily 5
Get five new use cases tomorrow morning
Free. Real sources. Unsubscribe any time.
Related use cases
Hot-swap agents mid-session and compose them into workflows
Endo is a "higher-order harness": one UI that uses any agent provider with your existing subscriptions, swaps agents mid-session and composes them into workflows. The author tested it by having Fable and Astra stage a mock presidential debate.
Get Microsoft Office running on Linux with Wine using Claude
With spare time and a Claude Max subscription, the author had Fable hack on Wine until desktop Microsoft Office ran on Linux with no virtual machine, then packaged the setup as Nix flakes.
Run a one-prompt game build across four agents and blind-judge them
Four AI agents got one prompt to build a complete game with no help. GPT-6 Astra said done after 32 minutes; Opus 5.5 was still adding things at 5 hours 38 minutes ($154). Blind AI judges scored Opus 9.0, Astra 7.5, Argon 6.7, Kimi K3 5.3.
Have an AI reverse engineer a device you own
Had the Fable model work out the music format of his self-playing piano system.