I recently tried to use GPT Astra and Anthropic models to see if they decipher the indus valley script, long story short - they didn't. I burned ~891M tokens on this across 3 weeks and several resets. The entire exploration is captured in a github repository with research log wrt directions and experiments conducted.

Some background on Indus valley script: The Indus script is the undeciphered system of signs left by the Indus Valley, or Harappan, civilization, which flourished in ancient Indian sub continent. Its signs were widely used around 2600–1900 BCE, including at Harappa and Mohenjo-daro.

There's a $1M award for decipherment. https://www.cnn.com/2025/02/28/asia/indus-valley-script-indi...