Is MCP + federated search killing the index?

This post argues that LLMs and protocols like MCP make enterprise search indexes *more* essential, not obsolete. It details the drawbacks of federated search (latency, limited data, inconsistent APIs, simple ranking, lowest common denominator filtering) and contrasts them with the benefits of a permission-aware index. The post highlights Glean's investment in custom crawlers, enterprise-adapted indexing and ranking (including semantic search and knowledge graphs), and continuous experimentation (cold-start deployment, topicality-aware ranking, calibration loops) as key differentiators. It positions the index as the most cost-effective and performant way to ground intelligent systems, emphasizing that larger context windows do not replace the need for precise, curated inputs from an index.