rtkmcp

Token-efficient MCP server for LLM development tools. Filters command output before it reaches your LLM context — 60-90% token savings with zero data loss.

Based on rtk-ai/rtk — Rust Token Killer by Patrick Szymkowiak (MIT). rtkmcp extracts the core filtering logic from RTK and re-packages it as a standalone MCP server that works with any MCP-compatible LLM client without requiring hooks or a separate RTK installation.

Install

macOS / Linux — one command:

curl -sSf https://raw.githubusercontent.com/omercanga/rtkmcp/main/install.sh | sh

Windows — one command (PowerShell):

irm https://raw.githubusercontent.com/omercanga/rtkmcp/main/install.ps1 | iex

Docker (no install required):

docker pull ghcr.io/omercanga/rtkmcp:latest

Cargo:

cargo install rtkmcp

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Configure (pick your client)

Add one of these to your MCP client config — same JSON for all clients:

{"mcpServers": {"rtkmcp": {"command": "rtkmcp"}}}

Claude Code

File: ~/.claude/settings.json

{
  "mcpServers": {
    "rtkmcp": {
      "command": "rtkmcp"
    }
  }
}

Cursor

File: .cursor/mcp.json (project) or ~/.cursor/mcp.json (global)

{
  "mcpServers": {
    "rtkmcp": {
      "command": "rtkmcp"
    }
  }
}

Windsurf

File: ~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "rtkmcp": {
      "command": "rtkmcp"
    }
  }
}

VS Code (GitHub Copilot)

File: .vscode/mcp.json

{
  "servers": {
    "rtkmcp": {
      "type": "stdio",
      "command": "rtkmcp"
    }
  }
}

Docker (any client)

{
  "mcpServers": {
    "rtkmcp": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-v", "${workspaceFolder}:/workspace",
        "-w", "/workspace",
        "ghcr.io/omercanga/rtkmcp:latest"
      ]
    }
  }
}

---

Tools

Tool	What it does	Savings
shell_run	Run any command, strip build noise	60-80%
errors_only	Run build/test, return ONLY failures	70-90%
read_file	Read file, strip comments/boilerplate	40-60%
git_status	Compact git status (porcelain)	85%
git_log	One-liner commit history	80%
git_diff	Condensed diff with file summaries	60-70%
list_dir	Compact directory tree	70%
search_code	Grep with per-file grouping	60%

Examples

# Instead of running "cargo build" directly:
shell_run(command="cargo build", cwd="/project")

# Run tests, see only failures:
errors_only(command="cargo test", cwd="/project")

# Read a large file without comments:
read_file(path="src/auth.rs", level="minimal")

# Read just the structure (signatures only):
read_file(path="src/auth.rs", level="aggressive")

# Git status in 3 lines instead of 24:
git_status(cwd="/project")

# Last 20 commits, one line each:
git_log(limit=20)

# See what changed vs main:
git_diff(args=["main...HEAD"])

# Find all usages of a function:
search_code(pattern="fn validate_token", path="src/", file_type="rs")

---

How it works

LLM (Claude / Cursor / Windsurf / ...)
        │  MCP tool call
        ▼
   rtkmcp server          ← single binary, no runtime deps
        │  subprocess
        ▼
  git / cargo / ...       ← native tools
        │  raw output
        ▼
   filter engine          ← strip noise, compress, group errors
        │  compact output
        ▼
   LLM context            ← 60-90% fewer tokens

No hooks. No config files. No runtime dependencies.

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Requirements

• git in PATH (for git tools)
• rg (ripgrep) in PATH — optional, falls back to grep for search_code
• Nothing else

---

Performance

Metric	Value
Binary size	~1.8 MB
Startup time	< 10 ms
Memory usage	< 5 MB
Runtime deps	None

---

Platforms

Platform	Binary
Linux x86_64	rtkmcp-linux-x86_64
Linux ARM64	rtkmcp-linux-aarch64
macOS Intel	rtkmcp-macos-x86_64
macOS Apple Silicon	rtkmcp-macos-aarch64
Windows x86_64	rtkmcp-windows-x86_64.exe
Windows ARM64	rtkmcp-windows-aarch64.exe

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Attribution

rtkmcp is built on the filtering logic from rtk-ai/rtk (Rust Token Killer), created by Patrick Szymkowiak and the RTK contributors.

The following components were ported and adapted from RTK's source:

rtkmcp module	Source in rtk-ai/rtk
filters/lang.rs	src/core/filter.rs — MinimalFilter, AggressiveFilter, language detection
filters/ansi.rs	src/core/utils.rs — strip_ansi()
filters/truncate.rs	src/core/filter.rs — smart_truncate()
filters/git.rs	src/cmds/git/git.rs — compact_diff(), filter_log_output(), format_status_output()
filters/build.rs	src/cmds/rust/cargo_cmd.rs — BlockStreamFilter, CargoBuildHandler
filters/noise.rs	src/core/runner.rs — noise line patterns

Original license: MIT — Copyright © 2024 Patrick Szymkowiak

rtkmcp is a derivative work and is distributed under the same MIT license. The MCP server layer, tool definitions, cross-platform distribution pipeline, and this repository are authored by omercanga.

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License

MIT — see LICENSE

Original RTK code portions: MIT © 2024 Patrick Szymkowiak (rtk-ai/rtk)