Repository Analysis

fmtlib/fmt

A modern formatting library

5.9 Low AI signal View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of fmtlib/fmt, a C++ project with 23,653 GitHub stars. SynthScan v2.0 examined 55,711 lines of code across 69 source files, recording 482 pattern matches distributed across 10 syntactic categories. The overall adjusted score of 5.9 places this repository in the Low AI signal band.

The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).

5.9
Adjusted Score
5.9
Raw Score
100%
Time Factor
2026-07-12
Last Push
23.7K
Stars
C++
Language
55.7K
Lines of Code
69
Files
482
Pattern Hits
2026-07-14
Scan Date
0.03
HC Hit Rate

What These Metrics Mean

Adjusted Score
Primary synthetic code indicator. Raw score normalised per 1,000 lines of code and multiplied by the temporal discount factor. This is the definitive comparative metric — use it to rank repositories by AI authorship density.
Raw Score
The unmodified sum of all severity-weighted, context-multiplied pattern match scores before temporal discounting. Reflects the absolute signal strength independent of when the repository was last active.
Time Factor
The temporal discount multiplier (0–100%) applied to the raw score. Repositories last updated before ChatGPT's launch (Nov 2022) receive a 5% factor. Full signal is only assigned to repositories active in the post-adoption era (Jan 2024+).
Pattern Hits
Total count of individual pattern matches across all files and categories. A high hit count with a low score may indicate a very large codebase with isolated AI snippets; a low count with a high score indicates dense, concentrated AI signatures.
HC Hit Rate
High+Critical pattern hits per file, averaged across the repository. This orthogonal signal catches repositories where a few files are densely packed with high-severity AI tells — a strong indicator even when the normalised score appears moderate due to codebase size.
Lines of Code / Files
Total lines and files analysed. The scanner examines 94 file extensions. These denominators are used to normalise the score, enabling fair comparison between repositories of vastly different sizes.

Score History

This chart maps the temporal evolution of the adjusted synthetic code score across successive scan runs. An upward trajectory indicates ongoing incorporation of AI-generated code or expanding LLM-assisted scaffolding; a stable or declining trajectory may reflect active human refactoring, code removal, or the adoption of stricter authorship policies. The dashed secondary line (right axis) independently tracks total raw pattern hit count, which can diverge from the normalised score when codebase size changes significantly between scans.

Severity Breakdown

Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.

CRITICAL 0HIGH 2MEDIUM 6LOW 474

Directory Score Breakdown

This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.

Pattern Findings

The scanner identified 482 distinct pattern matches across 10 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.

Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.

Over-Commented Block452 hits · 282 pts
SeverityFileLineSnippetContext
LOWtest/c-test.c1// Formatting library for C++ - the C API testsCOMMENT
LOWtest/posix-mock.h1// Formatting library for C++ - mocks of POSIX functionsCOMMENT
LOWtest/mock-allocator.h1// Formatting library for C++ - mock allocatorCOMMENT
LOWtest/util.h1// Formatting library for C++ - test utilitiesCOMMENT
LOWtest/test-assert.h1// Formatting library for C++ - test version of FMT_ASSERTCOMMENT
LOWtest/scan.h1// Formatting library for C++ - scanning API proof of conceptCOMMENT
LOWtest/gtest-extra.h1// Formatting library for C++ - custom Google Test assertionsCOMMENT
LOWtest/fuzzing/fuzzer-common.h1// Copyright (c) 2019, Paul DreikCOMMENT
LOWtest/fuzzing/build.sh1#!/bin/shCOMMENT
LOWtest/cuda-test/CMakeLists.txt1# We can find some usecases which follow the guide of CMake which usesCOMMENT
LOWtest/cuda-test/CMakeLists.txt21# providing another (non-CUDA) C++ source code.COMMENT
LOWtest/gtest/gtest/gtest-spi.h1// Copyright 2007, Google Inc.COMMENT
LOWtest/gtest/gtest/gtest-spi.h21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHTCOMMENT
LOWtest/gtest/gtest/gtest-spi.h121// A set of macros for testing Google Test assertions or code that's expectedCOMMENT
LOWtest/gtest/gtest/gtest-spi.h181// being part of the failure message.COMMENT
LOWtest/gtest/gtest/gtest.h1// Copyright 2005, Google Inc.COMMENT
LOWtest/gtest/gtest/gtest.h21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHTCOMMENT
LOWtest/gtest/gtest/gtest.h41//COMMENT
LOWtest/gtest/gtest/gtest.h61COMMENT
LOWtest/gtest/gtest/gtest.h81// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FORCOMMENT
LOWtest/gtest/gtest/gtest.h101// Copyright 2005, Google Inc.COMMENT
LOWtest/gtest/gtest/gtest.h121// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHTCOMMENT
LOWtest/gtest/gtest/gtest.h141// GOOGLETEST_CM0001 DO NOT DELETECOMMENT
LOWtest/gtest/gtest/gtest.h161// provide a default definition. After this header is #included, allCOMMENT
LOWtest/gtest/gtest/gtest.h181// GTEST_HAS_STD_WSTRING - Define it to 1/0 to indicate thatCOMMENT
LOWtest/gtest/gtest/gtest.h201// source version since 2008. The recommended valueCOMMENT
LOWtest/gtest/gtest/gtest.h221// GTEST_OS_HPUX - HP-UXCOMMENT
LOWtest/gtest/gtest/gtest.h241// most stable support. Since core members of the Google Test projectCOMMENT
LOWtest/gtest/gtest/gtest.h261//COMMENT
LOWtest/gtest/gtest/gtest.h281// the given Google Test flag.COMMENT
LOWtest/gtest/gtest/gtest.h301// is suppressed.COMMENT
LOWtest/gtest/gtest/gtest.h321// Extended Regular Expression syntax on UNIX-like platformsCOMMENT
LOWtest/gtest/gtest/gtest.h341// BiggestInt - the biggest signed integer type.COMMENT
LOWtest/gtest/gtest/gtest.h361#include <stdio.h>COMMENT
LOWtest/gtest/gtest/gtest.h381#include <locale>COMMENT
LOWtest/gtest/gtest/gtest.h401// contributors may be used to endorse or promote products derived fromCOMMENT
LOWtest/gtest/gtest/gtest.h421#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_COMMENT
LOWtest/gtest/gtest/gtest.h441// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORSCOMMENT
LOWtest/gtest/gtest/gtest.h461// Determines the platform on which Google Test is compiled.COMMENT
LOWtest/gtest/gtest/gtest.h481# define GTEST_OS_WINDOWS_TV_TITLE 1COMMENT
LOWtest/gtest/gtest/gtest.h501# define GTEST_OS_FREEBSD 1COMMENT
LOWtest/gtest/gtest/gtest.h521#elif defined __NetBSD__COMMENT
LOWtest/gtest/gtest/gtest.h541# define GTEST_FLAG_PREFIX_ "gtest_"COMMENT
LOWtest/gtest/gtest/gtest.h561// GTEST_DISABLE_MSC_WARNINGS_PUSH_(4800 4385)COMMENT
LOWtest/gtest/gtest/gtest.h581 _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"") \COMMENT
LOWtest/gtest/gtest/gtest.h601#if GTEST_OS_WINDOWS_MINGW && !defined(__MINGW64_VERSION_MAJOR)COMMENT
LOWtest/gtest/gtest/gtest.h621#endif // GTEST_OS_WINDOWSCOMMENT
LOWtest/gtest/gtest/gtest.h641COMMENT
LOWtest/gtest/gtest/gtest.h661// simple regex implementation instead.COMMENT
LOWtest/gtest/gtest/gtest.h681// clang defines __EXCEPTIONS if and only if exceptions are enabled before clangCOMMENT
LOWtest/gtest/gtest/gtest.h701# elif defined(__HP_aCC)COMMENT
LOWtest/gtest/gtest/gtest.h721COMMENT
LOWtest/gtest/gtest/gtest.h741# ifdef __GXX_RTTICOMMENT
LOWtest/gtest/gtest/gtest.h761# define GTEST_HAS_RTTI __has_feature(cxx_rtti)COMMENT
LOWtest/gtest/gtest/gtest.h781COMMENT
LOWtest/gtest/gtest/gtest.h801COMMENT
LOWtest/gtest/gtest/gtest.h821// architecture.COMMENT
LOWtest/gtest/gtest/gtest.h841#ifndef GTEST_HAS_STREAM_REDIRECTIONCOMMENT
LOWtest/gtest/gtest/gtest.h861#endifCOMMENT
LOWtest/gtest/gtest/gtest.h881#endifCOMMENT
392 more matches not shown…
AI Slop Vocabulary3 hits · 9 pts
SeverityFileLineSnippetContext
MEDIUMtest/gtest/gtest/gtest.h7407// This implementation is *not* meant to be as highly tuned or robustCOMMENT
MEDIUMtest/gtest/gtest/gtest.h7478// In practice, this can be used to test functions that utilize theCOMMENT
MEDIUMinclude/fmt/format.h3386 // Compilers are not aware of how to leverage the maximum value ofCOMMENT
Deep Nesting8 hits · 8 pts
SeverityFileLineSnippetContext
LOWsupport/docopt.py72CODE
LOWsupport/docopt.py301CODE
LOWsupport/docopt.py334CODE
LOWsupport/docopt.py402CODE
LOWsupport/docopt.py428CODE
LOWsupport/docopt.py57CODE
LOWsupport/printable.py133CODE
LOWsupport/python/mkdocstrings_handlers/cxx/__init__.py358CODE
Cross-Language Confusion2 hits · 8 pts
SeverityFileLineSnippetContext
HIGHsupport/release.py200 fmt_repo.push('origin', 'release')CODE
HIGHsupport/printable.py194 print(" if (0x{:x} <= cp && cp < 0x{:x}) return false;".format(a, a + b))STRING
Unused Imports7 hits · 7 pts
SeverityFileLineSnippetContext
LOWsupport/release.py12CODE
LOWsupport/release.py13CODE
LOWsupport/python/mkdocstrings_handlers/cxx/__init__.py17CODE
LOWsupport/python/mkdocstrings_handlers/cxx/__init__.py17CODE
LOWsupport/python/mkdocstrings_handlers/cxx/__init__.py19CODE
LOWsupport/python/mkdocstrings_handlers/cxx/__init__.py20CODE
LOWsupport/python/mkdocstrings_handlers/cxx/__init__.py20CODE
Verbosity Indicators3 hits · 4 pts
SeverityFileLineSnippetContext
LOWinclude/fmt/format-inl.h1275 // Step 1: integer promotion & Schubfach multiplier calculation.COMMENT
LOWinclude/fmt/format-inl.h1330 // Step 2: Try larger divisor; remove trailing zeros if necessary.COMMENT
LOWinclude/fmt/format-inl.h1362 // Step 3: Find the significand with the smaller divisor.COMMENT
Structural Annotation Overuse3 hits · 4 pts
SeverityFileLineSnippetContext
LOWinclude/fmt/format-inl.h1275 // Step 1: integer promotion & Schubfach multiplier calculation.COMMENT
LOWinclude/fmt/format-inl.h1330 // Step 2: Try larger divisor; remove trailing zeros if necessary.COMMENT
LOWinclude/fmt/format-inl.h1362 // Step 3: Find the significand with the smaller divisor.COMMENT
Excessive Try-Catch Wrapping2 hits · 4 pts
SeverityFileLineSnippetContext
MEDIUMdoc/ChangeLog-old.md2026 fmt::print("Error: ");CODE
MEDIUMdoc/ChangeLog-old.md3171 fmt::print("Error: {}");CODE
Self-Referential Comments1 hit · 3 pts
SeverityFileLineSnippetContext
MEDIUMsupport/release.py196 # Create a draft release on GitHub, then trigger the release workflow toCOMMENT
Modern Structural Boilerplate1 hit · 1 pts
SeverityFileLineSnippetContext
LOWsupport/docopt.py13__all__ = ['docopt']CODE