A warning about tiktoken, BPE, and OpenAI models. Tom MacWright warns that OpenAI's tiktoken Python library has a surprising performance profile: it's superlinear with the length of input, meaning someone could potentially denial-of-service you by sending you a 100,000 character string if you're passing that directly to tiktoken.encode()
.
There's an open issue about this (now over a year old), so for safety today it's best to truncate on characters before attempting to count or truncate using tiktoken
.
Recent articles
- How often do LLMs snitch? Recreating Theo's SnitchBench with LLM - 31st May 2025
- Talking AI and jobs with Natasha Zouves for News Nation - 30th May 2025
- Large Language Models can run tools in your terminal with LLM 0.26 - 27th May 2025