Nikui

Stop guessing where your technical debt is. Nikui combines LLM semantic reasoning with Git churn to prioritize exactly which files are rotting and need your attention.

Nikui is a code smell and technical debt analyzer that produces a prioritized hotspot report by combining LLM semantic analysis, static security scanning, structural duplication detection, and objective code metrics.

Example Output

See examples/ for a real scan of the Nikui codebase itself:

• nikui_self_scan.json — raw findings
• nikui_self_scan.html — interactive report
• config.json — config used for the scan (Ollama, Qwen2.5-Coder-7B)

Features

• LLM Semantic Analysis: Detects SOLID violations, silent failures, god objects, and other deep structural issues. Works with any OpenAI-compatible backend (OpenAI, MLX, LM Studio, Ollama).
• Static Security Scan: Comprehensive security and best-practice analysis via Semgrep.
• Verified Duplication: Two-tier structural detection using Simhash candidates verified by LLM to eliminate noise.
• Objective Metrics: Complexity scores, oversized files, and debug log detection via Flake8.
• Hotspot Matrix: Prioritizes findings using Stench × Churn — a complex file that changes frequently ranks higher than a smelly file no one touches.
• Interactive Report: Sortable HTML report with expandable findings per file.

Setup

1. Install Dependencies

# Install uv if you haven't
curl -LsSf https://astral.sh/uv/install.sh | sh

uv sync

2. Create Your Config

To customize Nikui for a repo, create a .nikui/config.json inside it:

mkdir .nikui
cp /path/to/nikui/examples/config.json .nikui/config.json

Nikui looks for .nikui/config.json in the target repo and falls back to sensible bundled defaults if none is found.

3. Configure an LLM Backend

Nikui works with any OpenAI-compatible LLM server. Set base_url and model in config.json.

Option A: OpenAI (fastest — recommended for large repos)

"ollama": {
  "base_url": "https://api.openai.com/v1",
  "model": "gpt-4.1-mini",
  "workers": 4
}

Set your key as an environment variable — never put it in config.json:

export OPENAI_API_KEY=sk-...

Option B: MLX (Apple Silicon)

pip install mlx-lm
mlx_lm.server --model mlx-community/Qwen2.5-Coder-14B-Instruct-4bit --port 8080

"ollama": {
  "base_url": "http://localhost:8080/v1",
  "model": "mlx-community/Qwen2.5-Coder-14B-Instruct-4bit"
}

Option C: LM Studio (Windows / Linux / Mac)

Download LM Studio, load a model, and start the local server (default port 1234).

"ollama": {
  "base_url": "http://localhost:1234/v1",
  "model": "qwen2.5-coder-14b-instruct"
}

Option D: Ollama

ollama pull qwen2.5-coder:14b
ollama serve

"ollama": {
  "base_url": "http://localhost:11434/v1",
  "model": "qwen2.5-coder:14b"
}

LLM is optional. If no backend is running, the semantic analysis and duplication verification stages are skipped gracefully.

Usage

# Full scan
uv run nikui smell <repo_path>

# Targeted scan (specific engines only)
uv run nikui smell <repo_path> --stages duplication semgrep

# Diff mode: Analyze only changed files since a base branch (CI optimization)
uv run nikui smell <repo_path> --diff origin/main

# Save to a specific output file
uv run nikui smell <repo_path> --output my_scan.json

# Generate HTML report (automatically finds and processes the latest scan)
uv run nikui report <repo_path>

GitHub Action & CI/CD: The "Stench Guard"

Nikui is designed for CI/CD with its Diff-Aware scanning mode. Instead of scanning the entire repo on every PR, Nikui can focus exclusively on the delta.

Key CI Features:

• --diff <base>: Only runs semantic, security, and metric analysis on modified files.
• Stateful Duplication: Caches Simhashes in .nikui/fingerprints.json to detect if new code is a clone of existing code without re-indexing the whole repo.
• Delta Prioritization: Focuses LLM reasoning on changed code to keep CI fast and costs low.

See examples/nikui_gh_action.yml for a production-ready GitHub Action template.

How It Works: The Hotspot Matrix

Hotspot Score = Stench × Churn

• Stench: Weighted sum of all findings in a file. Weights are configurable in config.json (e.g., Security = 50, Architectural Flaw = 20).
• Churn: Number of times the file has been modified in Git history.
• Result: Files classified into quadrants — Toxic, Frozen, Quick Win, or Healthy.

Configuration

• config.json — exclusion patterns, LLM settings, Semgrep rulesets, Flake8 ignores, stench weights
• nikui/prompts/ — LLM rubrics for smell detection and duplication verification
• nikui_results/ — all scans and reports saved automatically with timestamps

Prior Art & References

Nikui is built on the shoulders of giants in the software forensics and maintainability space:

• Hotspot Analysis: Based on Adam Tornhill's work in "Your Code as a Crime Scene", specifically the methodology of combining logical coupling (churn) with technical debt (stench) to identify high-risk areas.
• Code Smells: Inspired by Michael Feathers ("Working Effectively with Legacy Code") and Robert C. Martin ("Clean Code").
• Structural Duplication: Utilizes the Simhash algorithm (Charikar, 2002) for high-performance near-duplicate detection, verified via LLM semantic analysis.
• Static Analysis: Powered by Semgrep for security-focused pattern matching.

Contributing

Contributions are welcome. To get started:

1. Fork the repo and create a branch
2. Install dependencies: uv sync
3. Run tests before and after your change: uv run pytest
4. Run the linter: uv run flake8 nikui/
5. Open a pull request with a clear description of what you changed and why

Good areas to contribute:

• New smell detection engines
• Prompt improvements (nikui/prompts/)
• Support for additional languages in the dependency engine
• Report UI enhancements (nikui/report_template.html)

License

Apache 2.0 — see LICENSE

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Created by amirshk