Jsii

The project name of AWS's jsii (TypeScript multi-language binding toolchain), a single o200k token (id 114318) — likely GitHub-corpus residue with a near-initial, under-trained embedding.

"Jsii"

Observed behaviors

• 01In oh-my-pi's scan of 1.05M production tool calls, it hides as a sub-token inside surface strings like `Jsii_commentary` and is one of the glitch tokens triggering GPT-5.4/5.5 to leak Harmony protocol headers as plain text into tool arguments (163 leaks per million calls on gpt-5.4; 25 per million on gpt-5.5).GitHub

References

• GPT-5.x tool-call Harmony header leakage analysis (oh-my-pi) — GitHub

Related tokens