Knots

A fast multi-language code complexity analyzer built on tree-sitter. Knots measures traditional complexity metrics alongside two AI-specific cost scores — AIRD (AI Reasoning Difficulty) and AICP (AI Context Pressure) — to identify which functions are genuinely expensive to modify with AI assistance.

Features

• Multiple Complexity Metrics: McCabe, Cognitive, Nesting Depth, SLOC, ABC, Test Scoring
• AI Cost Metrics: AIRD (reasoning difficulty) and AICP (context pressure) — corpus-validated against 32,205 functions across 6 open-source C codebases
• Multi-Language: C, C++, Rust, Python, JavaScript, TypeScript, Ada, Go, Java, C#, Kotlin, Swift, PHP, Fortran, Scala, and Lua — same metrics and thresholds across all supported languages
• Testability Matrix: Categorize functions by complexity and testability
• Multiple Output Formats: text, SARIF, JSON, NDJSON (find/xargs-composable), CSV
• CI Threshold Enforcement: exit 1 on any threshold violation; recommended --aird-threshold 85
• Pre-commit Hook: native integration, no shim scripts required
• Validated: McCabe matches pmccabe exactly; Cognitive matches Mozilla rust-code-analysis at 1.004× mean ratio (11,365 Rust functions)

Installation

Prebuilt binary from PyPI (no Rust toolchain, installs in seconds):

pipx install knots          # or: uv tool install knots

From crates.io:

cargo install knots

Or from source:

git clone https://github.com/brandon-arrendondo/knots.git
cd knots
cargo build --release

No C compiler or build system required.

Quick Start

# Single file
knots src/main.c

# Recursive directory
knots -r src/

# CI gate — fail if any function has AIRD > 85
knots -r src/ --aird-threshold 85

# Adopt the gate on a legacy codebase: snapshot today, then fail only on regressions
knots -r src/ --aird-threshold 85 --baseline .knots-baseline.json --write-baseline
knots -r src/ --aird-threshold 85 --baseline .knots-baseline.json

# Gate only the functions you actually touched (no new debt in this change)
knots -r src/ --aird-threshold 85 --changed

# SARIF for GitHub Code Scanning
knots -r --format sarif src/ > knots.sarif

# Corpus analysis — one JSON record per function
find . -name "*.c" -o -name "*.rs" | xargs knots --format ndjson > metrics.ndjson

# Testability matrix
knots -m src/main.c

Complexity Indicators

Based on max(McCabe, cognitive):

Command-Line Options

knots [OPTIONS] [FILE]...
knots [OPTIONS] --compile-commands <FILE>

Options:
  -r, --recursive                   Recursively process all supported source files in directories
  -v, --verbose                     Show detailed per-function analysis
  -m, --matrix                      Show testability matrix categorization
  --compile-commands <FILE>         Use compile_commands.json to get file list
  --include <FILE>                  Include filter rules from JSON file (whitelist)
  --exclude <FILE>                  Exclude filter rules from JSON file (blacklist)
  --exclude-path <PATTERN>          Exclude files whose path matches this regex (repeatable)
  --format <FORMAT>                 text (default) | sarif | json | ndjson | csv
  --mccabe-threshold <N>            Exit 1 if any function exceeds this McCabe complexity
  --cognitive-threshold <N>         Exit 1 if any function exceeds this cognitive complexity
  --nesting-threshold <N>           Exit 1 if any function exceeds this nesting depth
  --sloc-threshold <N>              Exit 1 if any function exceeds this SLOC count
  --abc-threshold <F>               Exit 1 if any function exceeds this ABC magnitude
  --return-threshold <N>            Exit 1 if any function exceeds this return count
  --aird-threshold <N>              Exit 1 if any function exceeds this AIRD (AI Reasoning Difficulty) score (recommended: 85)
  --aicp-threshold <N>              Exit 1 if any function exceeds this AICP (AI Context Pressure) score
  --external-calls-threshold <N>    Exit 1 if any function exceeds this external call count
  --unreachable-blocks-threshold <N> Exit 1 if any function has more than this many unreachable (dead-code) basic blocks (C/C++/Rust only)
  --report <FILE>                   Write a detailed per-function report to this file (opt-in)
  --baseline <FILE>                 Ratchet mode: gate only on regressions vs. this snapshot (see docs/baseline.rst)
  --write-baseline                  Snapshot current scores to --baseline and exit without gating
  --since <REF>                     Gate only functions overlapping lines changed since this git ref
  --changed                         Gate only functions changed in the working tree (sugar for --since HEAD)
  --explain <METRIC>                Explain a metric (e.g. aird, aicp) and how to lower it, then exit
  --find-duplicates                 Report structurally duplicated functions across the corpus (--recursive only)
  --include-fixture-pairs           Keep tests/pass vs tests/fail fixture pairs in --find-duplicates output (excluded by default)
  --include-trivial-duplicates      Keep small-body, low-repeat groups (getters, one-assert tests) in --find-duplicates output (excluded by default)
  --dump-duplicates <FILE>          Write a JSON snapshot of --find-duplicates results, for later comparison via --diff-duplicates
  --diff-duplicates <BEFORE> <AFTER>  Compare two --dump-duplicates snapshots and summarize resolved/new/shrank/grew groups; exits without needing corpus files
  -j, --jobs <N>                    Parallel analysis threads (0 = auto-detect, 1 = sequential, default: 0)
  -h, --help                        Print help
  -V, --version                     Print version

Documentation

Full documentation is in the docs/ directory (Sphinx/RST):

• Installation
• Quick Start & Usage Examples
• CLI Reference
• Metrics Reference — AIRD/AICP formulas, corpus validation
• Output Formats — JSON schema, SARIF, NDJSON corpus patterns
• CI Integration — GitHub Actions, pre-commit hook
• Baseline / Ratchet Mode — adopt the gate on legacy code, fail only on regressions
• Filter Rules — --include/--exclude whitelists/blacklists
• knots.toml & Inline Suppression — TOML thresholds/exclusion, tools:off/tools:suppress comments
• Test Quality Analysis — knots-test-complexity companion tool
• Alternatives Comparison — vs. lizard, rust-code-analysis, clippy; cognitive algorithm differences
• Troubleshooting

License

MIT