aifmt
Make visual text content just work.
An MCP server + Copilot CLI plugin that fixes, validates, and generates visual text content — boxes, tables, bars, tree diagrams — for AI coding assistants.
The Problem
LLMs generate text token-by-token with no concept of column alignment. len("📦") returns 1, but the character renders wider on screen. This causes every AI-generated box, table, and tree diagram to be misaligned.
Before (LLM output — borders don’t line up):
┌────────────────────┐
│ Status: deployed │
│ Tests: 142 passing │
│ Coverage: 98.5% │
└────────────────────┘
After fix(content, mode="boxes"):
┌────────────────────┐
│ Status: deployed │
│ Tests: 142 passing │
│ Coverage: 98.5% │
└────────────────────┘
aifmt replaces len() with rendering-profile-aware visual width measurement so alignment is always correct.
Key Discovery: GitHub Emoji = 2.5 Columns
Through empirical testing, we discovered that GitHub renders emoji at 2.5 monospace columns — not the 2.0 that Unicode specifies and terminals use.
| Platform | Emoji width | CJK width |
|---|---|---|
| Terminal emulators | 2.0 cols | 2.0 cols |
| GitHub markdown | 2.5 cols | 2.0 cols |
This has a critical consequence:
- Even emoji count per line (0, 2, 4…) → integer total → ✅ perfect alignment
- Odd emoji count per line (1, 3, 5…) → fractional total → ❌ impossible to align
aifmt detects this and emits ⚠ warnings instead of silently producing broken output.
Read the full discovery story →
MCP Tools
| Tool | Description |
|---|---|
fix |
Repair misaligned boxes, tables, bars, and tree diagrams |
validate |
Check for alignment issues without modifying |
generate |
Create diagrams via Mermaid or PlantUML |
targets |
List rendering profiles (GitHub, terminal, custom) |
Quick Links
- Getting Started — Install and configure
- Tools Reference — Detailed tool documentation with examples
- The 2.5 Discovery — How we found the fractional emoji width
- Python API — Use the library directly
- Contributing — Development setup and guidelines