Context engines

The tools that decide what enters the context window: semantic engines, code graphs, repo packers, output filters, and local search indexes.

Augment Code - the coding platform whose core is a real-time semantic Context Engine feeding Auggie and Cosmos.
Graft - NanoNets’ MIT context layer feeding agents a code graph instead of grep, 8.4k stars in twelve weeks with every benchmark still the vendor’s own.
Graphify - the local AST knowledge graph exposed as a /graphify skill and MCP server, structure over similarity, no vectors.
qmd - Tobias Lütke’s local hybrid search engine for notes, docs, and knowledge bases, BM25 plus vectors plus reranking.
Repomix - the MIT CLI that packs a whole repo into one AI-friendly file, retrieval-free by design.
rtk - the Rust CLI proxy that filters agent command output before it enters the context window.
Semble - the local static-embedding-plus-BM25 code search index that indexes in under a second on any CPU, snippets instead of grep-and-read.
Sourcegraph code context platform - code search repositioned as the retrieval layer for agents, with value showing up above roughly 400K lines.

Its members are compared on shared rows in the Context Engines Feature Matrix.

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