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Quixoticals

Built at Built with Opus 4.7: a Claude Code hackathon · Apr 21, 2026 · Remote

Quixoticals — Demo video

~$8B/yr in U.S. security deposits are wrongfully withheld. In England, 30% of TDS arbitrations land partly or fully for the tenant. In Pakistan there is no deposit-protection scheme at all - tenants in Karachi/Lahore routinely lose 1–3 months of advance to bogus deductions. The pain is universal: tenants don’t know the law, landlords do. DepositBack closes that asymmetry. The user uploads three things: their lease, the landlord’s deduction letter, and a few move-out photos. A single autonomous Claude Opus 4.7 agent then runs a multi-tool session that: Lists every rule in the active jurisdiction’s statute corpus (statute_lookup). Extracts text and page images from each PDF (pdf_read). Classifies each visible mark in every photo as “ordinary wear” vs. “chargeable damage” using Opus 4.7’s high-resolution vision (vision_analyze), citing the Connell v. Brownstein-Louis Co. (1927) standard for California and the equivalent rule for each other jurisdiction. Maps every line item in the deduction letter against statute, classifying each as valid, invalid, or excessive. Drafts a formal demand letter with verbatim statute citations (doc_draft). Pre-fills the appropriate court / scheme form for the jurisdiction (form_fill). The user watches the entire event stream live — every thinking step, every tool call, every result — over Server-Sent Events, then downloads the letter and the form. Adding a new jurisdiction is one JSON file in backend/data/statutes/. Five jurisdictions are live today: California (post-AB 12), New York, Texas, England & Wales, and Sindh, Pakistan (with Cantonments-Act fallback for DHA / Clifton Cantt / Faisal Cantt properties). DepositBack uses no RAG, no embeddings, no chunking — the entire lease, the entire deduction letter, the entire statute corpus, plus all photo descriptions fit in Opus 4.7’s 1M-token context in a single pass. This ~$8B/yr in U.S. security deposits are wrongfully withheld. In England, 30% of TDS arbitrations land partly or fully for the tenant. In Pakistan there is no deposit-protection scheme at all — tenants in Karachi/Lahore routinely lose 1–3 months of advance to bogus deductions. The pain is universal: tenants don’t know the law, landlords do. DepositBack closes that asymmetry. The user uploads three things: their lease, the landlord’s deduction letter, and a few move-out photos. A single autonomous Claude Opus 4.7 agent then runs a multi-tool session that: Lists every rule in the active jurisdiction’s statute corpus (statute_lookup). Extracts text and page images from each PDF (pdf_read). Classifies each visible mark in every photo as “ordinary wear” vs. “chargeable damage” using Opus 4.7’s high-resolution vision (vision_analyze), citing the Connell v. Brownstein-Louis Co. (1927) standard for California and the equivalent rule for each other jurisdiction. Maps every line item in the deduction letter against statute, classifying each as valid, invalid, or excessive. Drafts a formal demand letter with verbatim statute citations (doc_draft). Pre-fills the appropriate court / scheme form for the jurisdiction (form_fill). The user watches the entire event stream live — every thinking step, every tool call, every result — over Server-Sent Events, then downloads the letter and the form. Adding a new jurisdiction is one JSON file in backend/data/statutes/. Five jurisdictions are live today: California (post-AB 12), New York, Texas, England & Wales, and Sindh, Pakistan (with Cantonments-Act fallback for DHA / Clifton Cantt / Faisal Cantt properties). DepositBack uses no RAG, no embeddings, no chunking — the entire lease, the entire deduction letter, the entire statute corpus, plus all photo descriptions fit in Opus 4.7’s 1M-token context in a single pass. This eliminates the retrieval-error class of bugs that sank DoNotPay.eliminates the retrieval-error class of bugs that sank DoNotPay.

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