[{"type":"thinking","thinking":"As expected, `cost` isn't a shell command. The `/cost` is a slash command of the Nguyen CLI itself — it must be typed by the user directly into the CLI prompt, not executed by me. Let me tell the user how to run it.","signature":""},{"type":"text","text":"`/cost` is a **slash command of the Nguyen CLI itself** — it's not a shell command I can run for you. You need to type it directly into the CLI prompt:\n\n```\n/cost\n```\n\n(or `/cost project` if that variant exists in your version).\n\nSlash commands (`/help`, `/cost`, `/fast`, etc.) are handled by the CLI before they reach me, so they don't come through my tool interface. Type it yourself at the prompt and the usage/cost report will display for you.\n\nFor what it's worth, if you're tracking spend: this session was heavier than average — ~25–30 Lean compile iterations with large Mathlib imports is token-intensive work. Future sessions of the same kind (ii′-1b(iii), ii′-2/3/5) will be similar; the design/planning sessions (ii′-0 style) are much lighter."}]