Updated readme hierarchy

Author: Karthi Thyagarajan

README.md

@@ -8,4 +8,5 @@ Sample applications and code from the GCP Database Blackbelt team demonstrating
 |----------|-------------|
 | [spanner-ai](spanner-ai/) | AI and Agent integrations with Spanner, including chatbots and ADK samples |
 | [spanner-tools](spanner-tools/) | Utility tools and applications for managing and operating Spanner |
+| [spannergeo-s2](spannergeo-s2/) | Geo-Spatial Indexing on Spanner using the S2 Geometry Library |
 | [vector-hybrid-search](vector-hybrid-search/) | Vector search, full-text search, and hybrid search implementations |

spanner-ai/README.md

@@ -7,5 +7,5 @@ Samples demonstrating AI and Agent integrations with Google Cloud Spanner.
 | Sample | Description | Technologies |
 |--------|-------------|--------------|
 | [customer-service-agent](spanner-adk/customer-service-agent/) | E-commerce chatbot application using Google Agent Development Kit (ADK) with Spanner as the backend database. Supports natural language queries for order lookup, product search, and customer service. | Google ADK, Python, React, Spanner |
-| [spanner-mcp](spanner-mcp/) | Gemini CLI Extension for interacting with Google Cloud Spanner using natural language prompts to manage databases, execute queries, and explore schemas. | Gemini CLI, Python, Spanner API |
+| [spanner-mcp](spanner-mcp/) | Samples and extensions related to the Model Context Protocol (MCP) for Spanner, including the Gemini CLI Extension and Spanner Graph demo. | Gemini CLI, Python, Spanner API |
 | [spanner-remote-function-openai](spanner-remote-function-openai/) | Generate OpenAI Embeddings with Spanner Remote UDFs. | Google Cloud Spanner, Cloud Run Functions, OpenAI API, Python |