# Token Usage Logging

Append a row to `## AI Usage Log` at the end of the artifact file when a TAS command completes. Lightweight audit trail of which commands touched the artifact — **no token estimation** (the char/4 guess was inaccurate; use `/cost` or `/context` for real numbers).

## Process

1. Artifact file = the one named by the invoking command (commands pass it explicitly — do not guess "last edited file").
2. If `## AI Usage Log` is absent → append the section header + table + first row. Else → append one row.
3. Silent on success — no output to conversation.

DO NOT apply when: user manually edits the file, or for non-TAS commands.

## Format

```markdown
---

## AI Usage Log

| # | Date | Command |
|---|------|---------|
| 1 | YYYY-MM-DD | /tas-{name} |
```

The format is stable — you do not need to re-read this file once you know it; just append the next numbered row.