Semble
Fast, accurate code search for AI agents using ~98% fewer tokens.
Semble is a practical pick for agent developers who want fast, private code search without cloud dependencies. Its token efficiency and CPU-only operation are clear wins, though teams needing managed hosting, access controls, or real-time reindexing should look elsewhere.
- Developers using AI coding agents (Claude Code, Cursor, Codex, etc.)
- Teams wanting instant code navigation without full-file reads
- Users needing local, private code search with no external API calls
- Agent builders integrating code retrieval into MCP workflows
- Users who need cloud-hosted or managed code search
- Those requiring search across non-code document formats
- Teams that need granular access control or permissions
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In short
Semble — Fast, accurate code search for AI agents using ~98% fewer tokens. Best for Developers using AI coding agents (Claude Code, Cursor, Codex, etc.), Teams wanting instant code navigation without full-file reads, Users needing local, private code search with no external API calls. Free to use.
What's new in Semble
Checked 14 days agoAcross the latest 1 update: 1 news mention.
Viability Score
How likely is Semble to still be operational in 12 months? Based on 4 signals — momentum (how recently it shipped), wrapper dependency, revenue model, and web presence.
Last calculated: July 2026
How we score →Key Features
- Natural-language code search
- Code-aware chunking via tree-sitter
- Static Model2Vec embeddings using code-specialized model
- BM25 lexical retrieval for identifiers and APIs
- Reciprocal Rank Fusion (RRF) of semantic and lexical scores
- Adaptive weighting for symbol-like vs. natural-language queries
- Definition boost for defining vs. referencing chunks
- Identifier stem matching (e.g., parse config matches parseConfig)
- File coherence reranking
- Noise penalties for test files, legacy code, and stubs
- Indexes local paths and git URLs
- MCP tools: search and find_related
- Zero-setup install (semble install)
- Runs entirely on CPU, milliseconds per query
- Uninstall via semble uninstall
About Semble
Semble is a code search library built for agents. It returns exact code snippets on natural-language queries instantly—using roughly 98% fewer tokens than a grep+read workflow. Designed for coding agents like Claude Code, Cursor, Codex, OpenCode, and Gemini, Semble runs entirely on CPU with no API keys, GPU, or external services. It can be used as an MCP server, a CLI tool, or a dedicated sub-agent. The library indexes an average repository in about 250 ms and answers queries in roughly 1.5 ms, all while achieving 99% of the retrieval quality of larger code-specialized transformers (NDCG@10 of 0.854 on benchmarks). Its hybrid retrieval combines static Model2Vec embeddings (using the code-specialized potion-code-16M model) with BM25 lexical search, fused via Reciprocal Rank Fusion and reranked with code-aware signals like definition boosts, identifier stem matching, file coherence, and noise penalties. Semble supports indexing of local paths and git URLs, and its MCP tools (search and find_related) integrate with any MCP-compatible agent. For agent builders needing private, offline, and token-efficient code navigation, Semble offers a zero-setup, open-source alternative to cloud-based retrieval-augmented generation (RAG) or transformer-heavy approaches.
Behind the Verdict
If you build or use AI coding agents, Semble addresses a real pain: the cost and latency of reading entire files. By returning only relevant chunks, it slashes token usage by roughly 98% compared to grep+read workflows. The hybrid static-embedding plus BM25 approach delivers accuracy on par with transformer-based code search—NDCG@10 of 0.854—without the GPU requirement. We'd reach for this when working with Claude Code or Cursor on a multi-file codebase; the MCP integration is especially slick, giving agents two tools (search and find_related) that feel natural. Where Semble stumbles, it's largely by design: it's a local, library-level solution. There's no cloud dashboard, no team permissions, no real-time reindexing as files change. If you need shared search across a large organization or frequent incremental updates, you'll need to build those layers yourself. Compared to alternatives like CodeBERT or GPT-based code search, Semble is dramatically faster and cheaper at query time, but it won't match the depth of understanding from a large model for highly ambiguous queries. The open-source, MIT-licensed nature is a major plus for privacy and customisation. Best for solo developers and small teams who want instant, offline code navigation; less suited for enterprises seeking a managed service.
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Use Cases
- Search a large codebase with natural language questions like 'How is authentication handled?'
- Find related code given a specific file location using find_related MCP tool
- Integrate code retrieval into Claude Code or Cursor via MCP server
- Index a git repository by URL and query it without cloning manually
- Reduce token usage in agent workflows by returning only relevant snippets
Models Under the Hood
as of 2026-07-15
Limitations
- Semble is a local-only tool with no cloud or API-based collaboration features.
- It relies on tree-sitter for code chunking, which may have limited language support.
- As a code search library, it does not include code generation or explanation capabilities.
12-month cost
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Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
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