CS
indexless code search that understands code, comments and strings
Details
- External ID
- 47115409
- Source
- HN
- Company
- —
- Product
- CS
- Website domain
- github.com
- Launched
- Feb. 22, 2026
- Cohort
- —
- Upvotes
- 15
- Upvotes percentile
- 0.6469002695417789
- Tags
- —
- Fetched at
- Sept. 7, 2026, 9:25 p.m.
- Updated at
- Sept. 7, 2026, 9:25 p.m.
Description
I initially built cs (codespelunker) as a way to answer the question, can BM25 relevance search work without building an index?Turns out it can, and so I iterated on the idea, building it into a full CLI tool. Recently I wanted to improve it by adding relevance of tools like Sourcegraph or Zoekt but again without adding an index.cs uses scc https://github.com/boyter/scc to understand the structure of the file on the fly. As such it can filter searches to code, comments or strings. It also applies a weighted BM25 algorithm where matches in actual code rank higher than matches in comments (by default).I also added a complexity gravity weight using the cyclomatic complexity output from scc as it scans. So if you're searching for a function, the implementation should rank higher than the interface. cs "authenticate" --gravity=brain # Find the complex implementation, not the interface cs "FIXME OR TODO OR HACK" --only-comments # Search only in comments, not code or strings cs "error" --only-strings # Find where error messages are defined cs "handleRequest" --only-usages # Find every call site, skip the definition v3.0.0 adds a new ranker, along with a interactive TUI, HTTP mode, and MCP support for use with LLMs (Claude Code/Cursor).Since it's doing analysis and complexity math on the fly, it's slower than any grep. However, on an M1 Mac, it can scan and rank the entire 40M+ line Linux kernel in ~6 seconds.Live demo (running over its own source code in HTTP mode): https://codespelunker.boyter.org/ GitHub: https://github.com/boyter/cs
Enrichment
- Theme
- markdown editors and writing tools
- Vertical
- —
- Function
- Search & retrieval
- Audience
- Developer
- AI stance
- AI feature
- Project type
- Commercial product
- Normalized one-liner
- code search that understands code and comments
- Manually corrected
- False
Could you build this?
No Building an indexless, AST-aware BM25 search CLI that understands code semantics, comments, and strings across entire codebases at high speed requires specialized algorithms and low-level systems programming.
What it would actually take: This requires building a high-performance CLI (typically in Rust or C++) integrating Tree-sitter parsers for multiple languages to tokenize code into AST-derived categories (identifiers, comments, literals). It must implement streaming BM25 ranking algorithms on-the-fly across memory-mapped files without pre-indexing, using multi-threading (Rayon) and SIMD-accelerated text parsing to maintain interactive CLI latencies. This requires deep systems programming and information retrieval expertise.
Discussion
2 comments analyzed.
Competitors mentioned: Serena
Competitors
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Attention rank: #20 of 46 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).
Launched 116 days after the earliest competitor.
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