Move Hippo to dedicated repository

- Remove detailed Hippo documentation from Socratic Shell
- Replace with high-level overview and redirect to github.com/socratic-shell/hippo
- Update SUMMARY.md to reference single overview file
- Maintain connection to Socratic Shell collaboration patterns

Hippo now has its own focused development space while remaining
conceptually connected to the mindful collaboration approach.

Author: nikomatsakis

src/SUMMARY.md

@@ -26,7 +26,7 @@
     - [Frequently asked questions](./memory-bank/faq.md)
 - [Journal MCP Server](./journal-mcp-server/README.md)
     - [Design Document](./journal-mcp-server/design-doc.md)
-- [Hippo: AI-Generated Salient Insights](./hippo/README.md)
+- [Hippo: AI-Generated Insights Memory System](./hippo.md)
 
 # Dialectic
 

src/hippo.md

@@ -0,0 +1,46 @@
+# Hippo: AI-Generated Insights Memory System
+
+*An experiment in collaborative memory through reinforcement learning*
+
+## Overview
+
+Hippo is a memory system designed for AI-human collaboration that automatically generates insights during conversations and uses reinforcement learning to surface the most valuable ones over time.
+
+**Core Hypothesis**: AI-generated insights + user reinforcement > manual curation
+
+## Key Innovation
+
+Traditional memory systems require users to manually decide what to remember. Hippo tests whether AI can:
+1. **Generate insights automatically** during natural conversation consolidation moments
+2. **Learn from usage patterns** to identify which insights are truly valuable
+3. **Surface relevant context** at the right moments through semantic search
+
+## How It Works
+
+- **Automatic Generation**: AI creates insights during "Make it so" moments and checkpoints
+- **Temporal Decay**: Insights lose relevance over time unless reinforced
+- **Reinforcement Learning**: User feedback (upvotes/downvotes) affects future surfacing
+- **Context-Aware Search**: Finds insights from similar situations using array-based context matching
+- **Hybrid Workflow**: AI suggests reinforcement based on usage patterns, user confirms
+
+## Implementation
+
+Hippo is implemented as an MCP (Model Context Protocol) server providing tools for recording, searching, reinforcing, and modifying insights. It uses importance-weighted scoring with lazy evaluation of temporal decay.
+
+## Status & Repository
+
+Hippo has been spun out into its own dedicated repository for focused development:
+
+**🔗 [github.com/socratic-shell/hippo](https://github.com/socratic-shell/hippo)**
+
+The repository contains:
+- Complete technical design and MCP specifications
+- LLM usage prompts and integration guidance  
+- Realistic example dialogs demonstrating the full workflow
+- Delegate experiment validating that AI naturally searches memory for technical problems
+
+## Relationship to Socratic Shell
+
+Hippo emerged from exploring memory systems for the Socratic Shell collaboration patterns. While it's now a standalone project, it's designed to integrate seamlessly with the mindful collaboration approach - automatically capturing insights during consolidation moments and surfacing them during future conversations.
+
+The goal is to create a memory system that enhances rather than interrupts the natural flow of collaborative work.