business rule search

We Built claude-context's Architecture Ourselves in October 2025, and It Failed on Accuracy

claude-context is Zilliz's open source code search MCP server, around 11,800 stars, chunking along AST boundaries and serving hybrid BM25 and vector retrieval with Merkle tree incremental reindexing. The engineering is competent. We cannot credibly write a takedown of it, because we shipped the same architecture in October 2025, watched it fail on accuracy, and threw it away. This is what that cost us to learn.

A Call Graph Is Not a Specification, and CodeGraph Shows Exactly Why

CodeGraph went from launch on 18 January 2026 to roughly 47,000 stars in five months by mapping symbols and call edges locally, with no server and no cloud embedding call. It deserved every one of those stars. It also answers one class of question completely and another class not at all, and the second class is where production breaks.

Serena Knows Every Symbol in Your Codebase and None of the Meaning

Serena is the best open source symbol level tool for agents, with 25,200 stars, 170 contributors and over 40 languages behind a clean LSP to MCP design. A language server gives you exact call edges and zero intent. In the MSR 2026 dataset of rejected agentic pull requests, only 36% failed on the code itself and 31% failed on a decision the project had already taken, which is the third no symbol table can reach.

Sourcegraph Answers Where the Code Is. Agents Need to Know Why It Exists

Sourcegraph built the most complete cross repository code search anyone has shipped, and it did so on an assumption that held for fifteen years: a human is asking. Humans supply the meaning the index leaves out. An agent cannot, and at 10 million files a 1 million token window holds 0.01% of the estate, so the gap is not one model generation away.