semantic code 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.

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.

Everyone Open Sourced the Hands This Year. Nobody Open Sourced the Check

Agent runtimes got very good very fast. The thing that decides whether a change is correct across your other repositories did not get built at all. On cross repository blast radius, why AI code review misses it, and what a check actually needs.

Round-Trip Is a Signal, Not a Promise: How a Verifiable IR Checks Code Against Intent

A technical note on what 'verifiable' actually means in a verifiable code IR. Not a machine that rebuilds your code from a document, but a derived contract that every change gets checked against. Here is what a single verification check consists of, why round-trip is a signal and never a promise, and the honest boundary of what it can and cannot catch.

A Code Graph Disintegrates Your Code. A Verifiable IR Preserves It.

A code graph takes a whole, coherent program and shreds it into a bag of symbols and edges. It is genuinely useful, but it is a teardown, and the meaning never survives the pieces. A verifiable intermediate representation is the opposite move. It lifts your code into a higher layer that keeps the intent intact, then checks every change against it. Here is the difference between shredding and preserving, and why it decides everything downstream.

Why Vector Search and GraphRAG Both End in the Same Context Rot

Vector search and GraphRAG look like opposites, but they share the same final move. Parse the code, retrieve some of it, rerank it, and stuff it into the context window. That last step is where both of them rot, because a model that is handed a pile of chunks degrades the same way no matter how the pile was chosen. Here is why the retrieval layer is not the cure for context rot, and what is.

How We Hit 94% Accuracy at 20% of the Tokens Across 46 Repos

The claim that a verifiable IR beats vector search and GraphRAG only matters if the numbers hold up. So here is the run. 46 Kubernetes-ecosystem repositories, 150,000 files, 8 GB of code, measured end to end. What we tested, how we scored it, and why feeding the model 22x more context made it cheaper and more accurate at the same time.

What Verifiable Means for Code Context, and Why GraphRAG Can't Check Code Against Intent

Verifiable is the one word competitors cannot claim. A code graph extracts a shadow of your code and can never tell you whether the code still does what it is supposed to. A verifiable intermediate representation is a derived contract that every change gets checked against. Here is what verifiable actually means, why GraphRAG and vector search can only retrieve, and what continuous verification unlocks.

One Context Layer, Every AI Coding Tool: Serving a Verifiable IR Over MCP

Your team uses Claude Code, Cursor, Copilot, and Windsurf, and each one rebuilds an understanding of your codebase from scratch and shares nothing with the others. MCP is the standard that lets you stop doing that. Compile your repos once into a verifiable IR and serve it to every tool over one MCP endpoint. Here is why the context layer belongs outside the tool, and what changes when it does.

$13.30 to Compile 1,000 Files Into a Verifiable IR, Once

The objection to compiling a codebase into a verifiable IR is always cost. It sounds like Opus pricing across every file. It isn't. At open-source-model rates it runs about $13.30 per 1,000 files, you pay it once, and per-file diffing means you only ever re-pay for what changed. Here is the real economics of the verifiable context layer, and why the expensive thing is not building the IR but living without one.

AST vs Vector vs Graph vs IR: Four Ways to Give an LLM Your Codebase

Every tool that feeds your codebase to an AI coding agent picks one of four representations. AST parsing, vector embeddings, code graphs, or a verifiable intermediate representation. Here is what each one keeps, what each one throws away, and why the first three are features of the fourth.

Spec-Driven Development for Brownfield: Verify Code Against Intent With a Verifiable Code Context Layer

Specs and code drift apart the day after you write the PRD, because they are two separate documents that nobody keeps in sync. A verifiable context layer derives the spec a codebase actually implements and then continuously checks the code against it. Here is how spec-driven development works on a brownfield codebase, and why it needs a verifiable code IR that checks code against intent.

The Context Graph You Can Verify Code Against

Context graph is a term people understand and reach for. But most things called a context graph are one-way extractions you can read and never check anything against. The version worth wanting is the one you can verify code against, and that single requirement is what separates an index from a verifiable code IR. Here is what verification demands, and why it is the only honest test of a context graph.

Code Graph RAG, Explained, and Why a Verifiable IR Is the Next Step Past It

Code graph RAG fixed the biggest flaw in vector search. It follows real edges instead of guessing at similarity. But a graph of symbols is still not a graph of meaning, and it cannot tell you whether a change still does what the system is supposed to do. Here is how code graph RAG actually works, where it stops, and why a verifiable intermediate representation is the layer above it.

Semantic Code Search Is a Retrieval Problem. Context Is a Representation Problem.

Semantic code search keeps getting better at finding the right code, and it keeps disappointing teams who expected better answers from their AI tools. The reason is that those are two different problems. Finding code is retrieval. Understanding code is representation. Better retrieval over a poor representation has a ceiling, and here is why a verifiable code IR raises it.

GraphRAG for Codebases: What It Solves, Where It Breaks, and the Layer Above It

GraphRAG for codebases is a genuine step up from vector search. It follows real call edges instead of guessing at similarity, and it wins on architectural questions. But it breaks in three predictable places: cross-repo links that aren't call edges, the why behind the code, and anything that needs intent you can check changes against. Here is a clear-eyed map of what graph RAG for codebases solves, where it stops, and the verifiable context layer that sits above it.

From Code Graph to Context Graph: Why a Graph of Symbols Isn't a Graph of Meaning

Everyone building code intelligence ends up at a graph, and then they start calling it a context graph because plain code graph stopped feeling like enough. But adding the word context does not add meaning. A graph of symbols and a graph of meaning are different objects. Here is the line between them, and why crossing it requires a verifiable code IR, not more edges.

The Code Context Landscape — Every Major Approach Compared to ByteBell

A comprehensive map of the open source tools providing context to AI coding agents in 2026, grouped by underlying technical approach (vector embeddings, AST parsing, compiler indexers, and LLM-generated metadata), with an honest analysis of where each one wins and where ByteBell's cross-repo, on-prem, business-context graph is the right answer.

Why Vector Search, AST Parsers, and Raw LLMs All Fail at Code Intelligence — And What Actually Works

Vector embeddings treat code like english prose. AST parsers see structure but not meaning. Raw LLMs forget everything every session. Here is why the LLM compiler pattern with a persistent semantic graph is the only approach that actually works for cross-repository code intelligence, and why open source models at $7 per 1000 files make it practical today.

Why "Context Graph" Has Become the Most Misunderstood Term in AI Engineering

A technical deep-dive into LLM context management, the computational limits of context windows, and why every AI tool's 'context graph' solution might just be clever marketing around semantic search and RAG.

The Simple Graph RAG Strategy That Finally Makes Multi-Repository Code Changes Reliable

Vector search finds relevant code but misses the blast radius. Learn how combining lightweight code graphs with RAG creates cross-repository context that makes code changes across 50+ repositories predictable—without heavy graph infrastructure.

Semantic Code Search Explained With Examples From Real Codebases

Move beyond keyword matching with semantic code search. Learn how embeddings, function-level understanding, and knowledge graphs transform code discovery—plus why citations matter for enterprise teams who can't afford hallucinated answers.