# Open Ledger

- **Event:** [OpenAI GPT-5 Startup Hackathon](https://cerebralvalley.ai/e/gpt5)
- **When:** Aug 9 at 10:00 AM – Aug 10 at 5:00 PM (PDT)
- **Where:** Location TBA
- **Team:** [Pryce Yebesi](https://cerebralvalley.ai/u/prycey), [Cadi Zhang](https://cerebralvalley.ai/u/cadizhang)
- **GitHub:** https://github.com/openledger/TaxMCP
- **Demo video:** https://drive.google.com/drive/folders/13QZnccUin5B7lqRbBBZvsizAS9WTn-h8?usp=share_link
- **Gallery:** https://cerebralvalley.ai/e/gpt5/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/gpt5/hackathon/gallery/81

TaxMCP is a GPT‑5–powered 1040 tax calculation engine and benchmark harness. It orchestrates GPT‑5 with tool calls to authoritative IRS data (exact tax table lookups), evaluates outputs against TaxCalcBench TY24 ground truth (strict/lenient), and packages a reproducible CLI + MCP tool server.

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Markdown version of https://cerebralvalley.ai/e/gpt5/hackathon/gallery/81. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt