| name | toon-formatter |
| description | Compress and format structured data with TOON to cut prompt size without losing shape. Use for JSON, tables, logs, API responses, or repeated records when token budget matters. |
| disable-model-invocation | true |
| user-invocable | true |
TOON Formatter
Use TOON for structured data when you want JSON-level fidelity with fewer tokens.
It works best for repeated records, tables, logs, metrics, and API responses.
Expect roughly 30-60% savings on regular data.
Use TOON When
- Arrays have at least 5 similar items.
- Objects mostly share the same keys.
- Shape matters more than JSON punctuation.
- You want compact data in prompts, summaries, or agent handoffs.
Keep JSON When
- Arrays are tiny.
- Data is deeply nested or irregular.
- Another tool must consume JSON directly.
- The output is prose, instructions, or a one-off example.
Fastest Workflow
If the toon CLI is available, pipe structured output through it:
curl -s "https://api.example.com/data" | toon
cat data.json | toon
some_command | toon
toon is safe on non-JSON output and passes it through unchanged.
If you need a local file converter in this repo, use:
python3 claude/skills/toon-formatter/toon-convert.py input.json -o output.toon
python3 claude/skills/toon-formatter/toon-convert.py data.json --delimiter tab
Manual Formatting Rules
1. Pick the right array form
-
Inline for short primitive arrays: tags[3]: alpha,beta,gamma
-
Tabular for regular objects:
[2]{id,name}:
1,Alice
2,Bob
-
List form for mixed or irregular items:
[2]:
- name: Alice
role: admin
- error: timeout
2. Pick the delimiter
- Comma: default and most compact
- Tab: better when values contain commas
- Pipe: useful when you want markdown-like rows
3. Keep explanations short
State the format choice once, then show the data:
Using TOON for 150 user records (uniform shape, lower token cost).
Examples
API response
[2]{id,name,email}:
1,Alice,alice@example.com
2,Bob,bob@example.com
Nested keys with folding
server.host: localhost
server.port: 8080
database.host: db.example.com
Install
The standalone CLI is @toon-format/cli.
References
