Validate ASCII Diagram

ASCII diagrams produced by agents frequently have alignment issues — misaligned corners, uneven borders, broken connectors. LLMs cannot reliably count characters in their head. This skill uses a print-and-inspect loop to catch and fix alignment bugs.

Rules

1. Prefer Unicode box-drawing characters. Use ┌, ┐, └, ┘ for corners, ─ for horizontal borders, │ for vertical borders, and ┬, ┴, ├, ┤, ┼ for junctions. Only fall back to plain ASCII (+, -, |) if the user explicitly requests it or the target format cannot render Unicode. Never mix styles in the same diagram.
2. Every row of a box must be the exact same width — top border, content rows, and bottom border.
3. Pad short content lines with spaces so the right border │ lands in the same column on every row.
4. Connectors and arrows should clearly connect to the box borders they relate to. Verify gaps are intentional.
5. No tab characters. Tabs render at unpredictable widths and silently break alignment. Use spaces only.
6. No trailing whitespace. Invisible trailing spaces cause width mismatches that look correct but aren't.

Verification procedure

Do NOT try to validate by counting characters in your head. Instead, use the print-and-inspect loop below.

Step 0: Decide whether to delegate to a subagent