Use ~3.3 chars/token base ratio (more conservative than the previous ~4) and apply a non-ASCII density penalty that shifts toward ~2.5 chars/token for CJK, emoji, or symbol-heavy text. Prevents underestimation that could bypass the token gate on code-heavy or multilingual prompts. https://claude.ai/code/session_01K7BWJY2gUoJi6dq91Yc7nx