Glacier Grep

Glacier.Grep

[](https://www.nuget.org/packages/Glacier.Grep/) [](https://www.nuget.org/packages/Glacier.Grep/)

Glacier.Grep is a native, high-performance, zero-allocation C# search engine and index for .NET 10. Built to take on ripgrep within the Glacier ecosystem, it provides aggressive hardware acceleration (SIMD), concurrent work-stealing directory scanning, and built-in support for the Model Context Protocol (MCP).

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Key Features

• 🚀 SIMD-Accelerated Hot Path: Utilizes hardware-accelerated set searching via .NET 10 SearchValues and auto-vectorized scanning on raw UTF-8 bytes without string conversions.
• 📂 Lock-Free Directory Enumeration: Implements custom FileSystemEnumerable checking which evaluates file metadata (hidden status, symlinks) and ignore matches entirely on the stack before materializing path strings.
• ⚙️ Advanced Ignore File Support: Evaluates rules from .gitignore, .ignore, and .rgignore hierarchically, matching ripgrep's prioritized exclusion behavior.
• ⚡ Hybrid I/O Dispatcher: Automatically routes files based on size (using zero-copy Memory-Mapped Files for >1MB and RandomAccess read into ArrayPool for )` for zero heap allocation searches.
• 🤖 MCP Server Support: Built-in support for the Model Context Protocol, allowing seamless integration with AI agents and tools.

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Installation

To build and run Glacier.Grep, clone this repository and build using .NET 10 CLI:

dotnet build src/Glacier.Grep.Host/Glacier.Grep.Host.csproj -c Release

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Quick Start (CLI Mode)

You can run Glacier.Grep directly from the command line:

# Basic literal search
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "public class"

# Case-sensitive search with 2 lines of context in a specific directory
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "public class" --dir "C:\src\myproject" --sensitive --context 2

# Regex search restricted to C# files
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "void\s+\w+Async" --regex --globs "*.cs"

# Search hidden files, binary files, and invert the match (lines NOT containing "Oranges")
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "Oranges" --hidden --text --invert

# Limit search depth to 2 directories
dotnet run --project src/Glacier.Grep.Host/Glacier.Grep.Host.csproj "target" --max-depth 2

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MCP Server Setup

Glacier.Grep includes a built-in MCP (Model Context Protocol) server host, allowing you to use your search engine as a tool for AI agents (like Claude or Antigravity).

1. Build the Server

Build the host application in Release mode:

dotnet build src/Glacier.Grep.Host/Glacier.Grep.Host.csproj -c Release

2. Configure Your Client

Add the following entry to your mcp_config.json:

{
  "mcpServers": {
    "glacier-grep": {
      "command": "dotnet",
      "args": [
        "ABS_PATH_TO_REPO/src/Glacier.Grep.Host/bin/Release/net10.0/Glacier.Grep.Host.dll"
      ]
    }
  }
}

3. Available Tools

• search_grep: Performs a high-performance search across files in a directory.
• query (string, required): The search query (literal or regex).
• path (string, optional): Base directory to search.
• isRegex (boolean, optional): Treat query as regular expression.
• caseSensitive (boolean, optional): Perform case-sensitive match.
• contextLines (integer, optional): Lines of context to include around matches.
• fileGlobs (array of strings, optional): Filter files (e.g. ["*.cs"]).
• searchHidden (boolean, optional): Search hidden files and folders.
• searchBinary (boolean, optional): Search binary files (do not skip).
• invertMatch (boolean, optional): Invert the match (show lines that do NOT contain the query).
• maxDepth (integer, optional): Maximum recursion depth for subdirectories.

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Performance

Glacier.Grep is aggressively optimized for .NET 10 to saturate memory bandwidth, performing within ~1.2x of Ripgrep's raw Rust execution speed on typical developer workloads, and even outperforming it on case-sensitive paths.

Benchmark (Searching the entire Glacier/PolarsPlus workspace)

• Target: 590 files, 257.83 MB
• OS/Hardware: Windows (x64), modern multi-core CPU

| Engine | Query | Execution Time (Warmed) | Performance Ratio | | :--- | :--- | :--- | :--- | | Ripgrep (Rust) | "public class" (Sensitive) | 134.9 ms | 1.12x | | Glacier.Grep (.NET 10) | "public class" (Sensitive) | 120.4 ms | 1.00x (FASTER) | | Ripgrep (Rust) | "public class" (Insensitive) | 137.9 ms | 1.00x | | Glacier.Grep (.NET 10) | "public class" (Insensitive) | 210.4 ms | 1.52x (improved from 1.7x) | | Ripgrep (Rust) | "ThreadIndependentReaderWriterLock" (Insensitive) | 115.7 ms | 1.00x | | Glacier.Grep (.NET 10) | "ThreadIndependentReaderWriterLock" (Insensitive) | 142.3 ms | 1.23x (improved from 1.7x) |

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Architecture

1. Directory Traverser: Zero-allocation metadata filtration. Prunes ignored folders (like .git, node_modules, bin/) and applies .gitignore, .ignore, and .rgignore rules.
2. Hybrid I/O Dispatcher: Chooses the fastest reading technique depending on file size.
3. Search Core: Evaluates the bytes using ReadOnlySpan and JIT vectorization.
4. MCP Integration: Integrates the search capabilities over standard stdio JSON-RPC.

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Credits

Developed by Ian Cowley and Antigravity (Google DeepMind).

License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: ian-cowley
• Source: ian-cowley/Glacier.Grep
• License: MIT

Install and usage instructions live in the source repository linked above.