Thai Legal Data API/MCP — give Claude, ChatGPT & Grok precise Thai law (4× more accurate citations)
Thai law, as data — not prose. The new Thai Legal Data API/MCP lets you look up any มาตรา verbatim, search 39 Thai laws by meaning, find the Supreme Court decisions (ฎีกา) that interpret a specific section, and ask legal questions that are answered only from retrieved sources — with every citation machine-checked. The API never invents a case number — and it plugs straight into Claude, ChatGPT, Grok, or any assistant that speaks MCP.
What's inside
- 39 laws · 6,363 sections — the consolidated statute corpus behind OpenThai 2.0 Legal (ป.พ.พ., ป.อ., ป.วิ.พ., ป.วิ.อ., ประมวลรัษฎากร and more)
- 70,634 Supreme Court rulings with their หลักกฎหมาย (legal-principle) headnotes
- 99.7% citation-linked — go from a section straight to the case law that interprets it
- Every result links back to the official record at deka.supremecourt.or.th
We measured it: Claude gets 4× more accurate
Does giving an AI assistant real Thai legal data actually help? We benchmarked it: 25 questions from the nitibench-CCL legal QA dataset, answered by the same Claude model twice — once bare, once with the six iapp-mcp legal tools.
| Bare Claude | Claude + iapp-mcp | |
|---|---|---|
| Cites the correct มาตรา | 20% | 80% |
| Citation F1 | 0.093 | 0.380 |
4× more correct citations (claude-sonnet-5, n=25, gold-citation hit rate). Without tools, the model cites plausible neighbors — มาตรา 298 or 300 when the right answer is 299. With tools, it retrieves the real section text and cites 299 exactly. Even our strongest test model improved by 1.5× — and with the tools, every model we tested converged at ~80% accuracy.
Use it from Claude Code in one command
claude mcp add iapp-mcp -s user -e IAPP_API_KEY=YOUR_API_KEY -- uvx iapp-mcp
Then just ask in Thai: "หาฎีกาที่ตีความ ป.อ. มาตรา 335 หลังปี 2560". Works with Claude Desktop, ChatGPT, Grok, Cursor, and any MCP client — six legal tools ship in iapp-mcp 2.1.0.
Prefer REST? GET /v3/store/data/thai-legal/section?law=ประมวลกฎหมายอาญา§ion=335&with_deka=true — see the full documentation with live try-it demos.
Free during launch
All endpoints are free during the launch promotion (then 0.1 IC/request; /meta and /laws stay free forever). New accounts get 50 IC free — no credit card required.
For research use — not legal advice. Every result carries a link to the official Supreme Court record; verify there before relying on a ruling in practice.