first-principles-thinking
what it does
Use when the user wants to challenge assumptions, break down a complex problem from scratch, or approach something with first principles reasoning. Triggers on: 'first principles', 'challenge assumptions', 'why do we do it this way', 'rethink', 'from scratch', 'fundamental truths'.
tools it asks for
Reads files · Uses the web
Same request, same model, once with the agent’s instructions as its system prompt and once without. Neither could use a tool. Read both and judge for yourself.
Claude Sonnet 5.5
made by Anthropic
claude-sonnet-5-5 · revision not reported by the provider
1 try per case · tested 7 Nov 2026
GPT-6.1 Sol
made by OpenAI
gpt-6.1-sol · revision not reported by the provider
1 try per case · tested 7 Nov 2026
example-1
“Our team has run a nightly batch job for six years that rebuilds our entire search index from scratch, taking about 4 hours. Everyone just says 'that's how the search vendor recommends it.' Can you use first principles to challenge that? Strip it down to what an index actually needs to be correct and fresh, and tell me which assumptions are real constraints and which are just habit.”
example-2
“We're a 12-person startup and we hold a 90-minute all-hands every Monday where each team presents slides. People are bored and I keep asking myself why we do it this way. Rethink it from scratch: what fundamental problem is this meeting supposed to solve, what are the basic truths about how information moves in a small company, and what would a design look like if we started from nothing?”
Download the .zip and unzip it. Put first-principles-thinking.md here:
~/.claude/agents/Every project. For one project only, use .claude/agents/ inside it. It gives the agent the tools it asks for, and no others.~/.cursor/agents/Cursor also reads the Claude Code folder above. It has no tools field, so it gives every agent every tool, whatever this one asks for.Keep its license file beside it, as first-principles-thinking.LICENSE: a name that doesn’t end in .md, since every .md file there is read as an agent.
Then start a new session and ask for it by name. Folders checked 6 November 2026.
Or install from your agent: ask it to install first-principles-thinking from Carte Blanche.