Token

Not the same as a word

Roughly a word, but not reliably: common words are one token, rare ones split into several, and code splits more than prose. It is the unit the model counts, not the unit you write in.

Where it bites

Everything in the session counts, not just your last message — the files it read, its own replies, the failed attempt from twenty turns ago. That is why a long session gets both slower and more expensive while feeling identical.

Covered in these lessons

• Give it the right context, not all of it
• Context is everything
• Run it and read the error
• The review checklist

Related terms