Browser-only utilities
Free context engineering tools.
Estimate how much text costs, reserve output room, and see how a context window fills before you send a long prompt or wire a RAG pipeline.
Key facts
Free Context Engineering Tools
- Every tool runs client-side in the browser; pasted text and budget numbers are not sent to a server.
- The token counter uses the documented rough heuristic of about four characters per token.
- The context packer visualizes system instructions, conversation history, retrieved evidence, examples, memory, and reserved output as one budget.
- Use these tools as planning aids; exact tokenizer counts still depend on the model and tokenizer.
TOKEN ESTIMATE Token Counter Paste text to estimate tokens with the documented four-characters-per-token heuristic and compare the result against common context windows. BUDGET BAR Context Packer Plan a context window by allocating tokens to system instructions, history, retrieved evidence, examples, memory, and reserved output.