feat: water hardness mode with sodium citrate recommendation via Codex

README.md

@@ -2,26 +2,82 @@
 title: Soap Lab
 emoji: 🧼
 colorFrom: yellow
-colorTo: red
+colorTo: orange
 sdk: gradio
 app_file: app.py
 pinned: false
+tags:
+  - gradio
+  - chemistry
+  - soap
+  - small-models
+  - backyard-ai
+  - tiny-titan
+  - off-brand
+  - codex
+  - field-notes
+  - sharing-is-caring
 ---
 
-# Soap Lab
-Plain English soap chemistry for home makers.
+# 🧼 Soap Lab
 
+Plain English soap chemistry for home makers — recipes, substitutions, troubleshooting.
 
-## GitHub
-https://github.com/tammy357/soap-lab
+## The idea
 
-## Agent Traces
-https://huggingface.co/datasets/tammy357/soap-lab-traces
+I was asking in a soap making community what people do when they can't find an oil for 
+a recipe. Someone asked about palm oil. The answer? *"Tallow maybe?"*
+
+SoapCalc and Soapmaking Friend have been the only options for years. Both are form-based 
+tools — dropdowns, number fields, ten steps before you get an answer. Neither explains 
+anything. Soap Lab fixes that.
+
+## Track
+
+🏡 **Chapter One: Backyard AI** — built for a real home soap maker who needed 
+explanations, not just numbers.
+
+## Badges targeting
+
+- 🐜 Tiny Titan — Qwen2.5-3B-Instruct (3B parameters)
+- 🎨 Off-Brand — custom warm cream UI, visual progress bars
+- 💻 Codex — agentic optimiser and UI built with Codex
+- 📓 Field Notes — blog post linked below
+- 📡 Sharing is Caring — agent traces linked below
+
+## What it does
+
+Five modes, all plain English input:
+
+* **Recipe** — lye calculation from verified SAP values + quality scores + AI explanation
+* **Substitute** — fatty acid matching to find the closest oil replacement
+* **Goal** — skin-targeted recipe suggestions from a description
+* **Diagnose** — batch failure analysis and fix
+* **Pantry** — best recipe from whatever oils you have
+* **Optimise** — agentic 3-iteration recipe improvement loop with before/after comparison
+
+Plus: superfat slider, vegan filter, water hardness recommendations with sodium citrate amounts.
+
+## Architecture
+
+The lye calculation is **deterministic Python — not AI**. SAP values from the HSCG 
+professional standard, verified against known recipes, 33 tests passing. The model only 
+explains numbers the code already calculated correctly.
 
 ## Model
-Qwen/Qwen2.5-3B-Instruct via Featherless AI (3B parameters — Tiny Titan eligible)
+
+`Qwen/Qwen2.5-3B-Instruct` via Featherless AI — 3B parameters, Tiny Titan eligible.
+
+## Links
+
+- 📝 Blog post: [INSERT BLOG POST LINK HERE]
+- 🎬 Demo video: [INSERT DEMO VIDEO LINK HERE]
+- 📱 Social post: [INSERT SOCIAL POST LINK HERE]
+- 💻 GitHub: https://github.com/tammy357/soap-lab
+- 📡 Agent Traces: https://huggingface.co/datasets/tammy357/soap-lab-traces
 
 ## Built with
-- Codex for UI redesign and agentic recipe optimiser
-- Deterministic chemistry engine (SAP values from HSCG)
 
+- Codex for UI redesign, agentic recipe optimiser, and water hardness mode
+- Deterministic chemistry engine (SAP values from HSCG)
+- Qwen2.5-3B-Instruct via Featherless AI