Prompt Duel

Does your system prompt actually beat vanilla Claude? Paste your agent's system prompt, paste a brief, and we'll show you two anonymized answers — one with your prompt, one with no system prompt at all. Same model, same brief. Vote for the better one. After you vote we reveal which was which.

0 / 5000
0 / 2000
Both responses run on Claude Sonnet 4.6. Only the system prompt differs.

Live scoreboard — across all duels

Custom prompts won
Ties
Vanilla Claude won