Wrangling Untrusted File Formats Safely
This report presents the forensic synthetic code analysis of google/wuffs, a C project with 4,801 GitHub stars. SynthScan v2.0 examined 156,244 lines of code across 442 source files, recording 649 pattern matches distributed across 6 syntactic categories. The overall adjusted score of 4.4 places this repository in the Likely human-written 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).
Longitudinal tracking requires multiple scan runs. Once this repository is re-scanned after new commits land, this chart will visualise how the synthetic code signal evolves over time — enabling you to detect whether AI authorship is growing, stabilising, or being actively corrected by human engineers.
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.
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.
The scanner identified 649 distinct pattern matches across 6 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.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | build-fuzz.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | build-example.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | build-all.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | build-all.sh | 21 | # | COMMENT |
| LOW | cmd/wuffs-c/release.go | 161 | ) | COMMENT |
| LOW | cmd/wuffs-c/release.go | 181 | #pragma GCC diagnostic ignored "-Wimplicit-fallthrough" | COMMENT |
| LOW | cmd/wuffs-c/main.go | 1 | // Copyright 2017 The Wuffs Authors. | COMMENT |
| LOW | cmd/handsum/main.go | 1 | // Copyright 2025 The Wuffs Authors. | COMMENT |
| LOW | cmd/wuffs/main.go | 1 | // Copyright 2017 The Wuffs Authors. | COMMENT |
| LOW | cmd/commonflags/commonflags.go | 1 | // Copyright 2017 The Wuffs Authors. | COMMENT |
| LOW | cmd/dumbindent/main.go | 1 | // Copyright 2020 The Wuffs Authors. | COMMENT |
| LOW | cmd/dumbindent/main.go | 21 | // Pass -spaces=N or -tabs to use N spaces or 1 tab per indent level. The | COMMENT |
| LOW | cmd/dumbindent/main.go | 41 | // real 0m0.668s | COMMENT |
| LOW | cmd/ractool/gen.go | 1 | // Copyright 2019 The Wuffs Authors. | COMMENT |
| LOW | cmd/ractool/main.go | 1 | // Copyright 2019 The Wuffs Authors. | COMMENT |
| LOW | cmd/wuffsfmt/main.go | 1 | // Copyright 2017 The Wuffs Authors. | COMMENT |
| LOW | test/3pdata/fetch-pngsuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-blinksuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-golangsuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-tgasuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-webpsuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-bmpsuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-xzsuite.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/3pdata/fetch-xzsuite.sh | 21 | # Check out a specific commit (from February 2024). | COMMENT |
| LOW | test/3pdata/fetch-xzsuite.sh | 41 | # contains a backdoor: | COMMENT |
| LOW | test/3pdata/fetch-xzsuite.sh | 61 | # nigeltao/xz-tests-files at 6e0194063a6dc205d4db35e307778efe1c9f1875 does | COMMENT |
| LOW | test/3pdata/fetch-xzsuite.sh | 81 | # | COMMENT |
| LOW | test/data/hello.sh | 1 | #!/bin/bash -eu | COMMENT |
| LOW | test/data/artificial-thumbhash/make.go | 1 | // Copyright 2024 The Wuffs Authors. | COMMENT |
| LOW | test/data/artificial-thumbhash/make.go | 21 | // of the original thumbhash description or implementation. But "\xC3\xBE" is | COMMENT |
| LOW | …if/pixel-data-too-much-bad-lzw.gif.make-artificial.txt | 21 | # The frame area is 4 pixels and we supply 4 but then an invalid LZW code. | COMMENT |
| LOW | …icial-gif/multiple-loop-counts.gif.make-artificial.txt | 1 | # Feed this file to script/make-artificial.go | COMMENT |
| LOW | …f/pixel-data-too-much-good-lzw.gif.make-artificial.txt | 21 | # The frame area is 4 pixels but we supply 5 (that's still valid LZW data). | COMMENT |
| LOW | …a/artificial-gif/metadata-full.gif.make-artificial.txt | 21 | # Application Identifier "ICCRGBG1". | COMMENT |
| LOW | …ficial-gif/frame-out-of-bounds.gif.make-artificial.txt | 1 | # Feed this file to script/make-artificial.go | COMMENT |
| LOW | …ficial-gif/frame-out-of-bounds.gif.make-artificial.txt | 21 | # 5. Expand the image width×height to 4×5, so that no frames are clipped. This | COMMENT |
| LOW | …ficial-gif/frame-out-of-bounds.gif.make-artificial.txt | 41 | # but a surprised user filed https://github.com/golang/go/issues/20856 when | COMMENT |
| LOW | …l-deflate/distance-code-31.deflate.make-artificial.txt | 1 | # Feed this file to script/make-artificial.go | COMMENT |
| LOW | …a/artificial-bzip2/huffman-258.bz2.make-artificial.txt | 21 | bits 16 0xFFFF | COMMENT |
| LOW | …a/artificial-bzip2/huffman-258.bz2.make-artificial.txt | 61 | COMMENT | |
| LOW | test/data/artificial-xz-filter/make.go | 1 | // Copyright 2024 The Wuffs Authors. | COMMENT |
| LOW | …rtificial-jpeg/make-hippopotamus-bad-comment-length.go | 1 | // Copyright 2024 The Wuffs Authors. | COMMENT |
| LOW | …rtificial-jpeg/make-hippopotamus-bad-comment-length.go | 21 | // the itu-t81.pdf spec section B.1.1.4 "Marker segments") but libjpeg-turbo is | COMMENT |
| LOW | …data/artificial-jpeg/make-hippopotamus-sof-dht-swap.go | 1 | // Copyright 2024 The Wuffs Authors. | COMMENT |
| LOW | …data/artificial-jpeg/make-hippopotamus-sof-dht-swap.go | 21 | // | COMMENT |
| LOW | test/c/mimiclib/jpeg.c | 1 | // Copyright 2023 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/webp.c | 1 | // Copyright 2024 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/xxhash.c | 1 | // Copyright 2023 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/lzma.c | 1 | // Copyright 2023 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/deflate-gzip-zlib.c | 1 | // Copyright 2017 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/openssl.c | 1 | // Copyright 2023 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/gif.c | 1 | // Copyright 2017 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/gif.c | 41 | COMMENT | |
| LOW | test/c/mimiclib/png.c | 1 | // Copyright 2020 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/png.c | 21 | // #define WUFFS_MIMICLIB_USE_STB_IMAGE_INSTEAD_OF_LIBPNG 1 | COMMENT |
| LOW | test/c/mimiclib/png.c | 281 | for (size_t i = 0; i < quirks_len; i++) { | COMMENT |
| LOW | test/c/mimiclib/bzip2.c | 1 | // Copyright 2022 The Wuffs Authors. | COMMENT |
| LOW | test/c/mimiclib/stb.c | 1 | // Copyright 2023 The Wuffs Authors. | COMMENT |
| LOW | test/c/std/json.c | 41 | // To use that single file as a "foo.c"-like implementation, instead of a | COMMENT |
| LOW | test/c/std/json.c | 3441 | COMMENT | |
| 562 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | build-fuzz.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | build-example.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | build-all.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-pngsuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-blinksuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-golangsuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-tgasuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-webpsuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-bmpsuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/3pdata/fetch-xzsuite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | test/data/hello.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | hello-wuffs-c/run.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | script/print-nia-checksums.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | script/confirm-matches-djpeg.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | script/bench-history.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | script/print-mzcat-checksums.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | script/run-json-test-suite.sh | 12 | # ---------------- | COMMENT |
| MEDIUM | doc/note/enumerated-media-types.txt | 2 | # ---------------------- | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM⚡ | test/data/nobel-prizes.json | 1 | {"prizes":[{"year":"2019","category":"chemistry","laureates":[{"id":"976","firstname":"John","surname":"Goodenough","mot | CODE |
| MEDIUM⚡ | test/data/nobel-prizes.json | 1 | {"prizes":[{"year":"2019","category":"chemistry","laureates":[{"id":"976","firstname":"John","surname":"Goodenough","mot | CODE |
| MEDIUM⚡ | test/data/nobel-prizes.json | 1 | {"prizes":[{"year":"2019","category":"chemistry","laureates":[{"id":"976","firstname":"John","surname":"Goodenough","mot | CODE |
| MEDIUM | internal/cgen/liveness.go | 50 | // Essentially, the state transitions are: strong is sticky, weak to strong | COMMENT |
| MEDIUM | internal/cgen/base/token-public.h | 93 | // for 1_DST_1_SRC_COPY) are in the FOO format. Definitely means that the lack | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | cmd/ractool/data.go | 136 | $ # Create a shared dictionary. Using zstd-the-program produces a | CODE |
| MEDIUM | cmd/ractool/main.go | 137 | $ # Create a shared dictionary. Using zstd-the-program produces a | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | hello-wuffs-c/wuffs-parse.c | 35 | // // No need to call wuffs_demo__parser__initialize, but don't forget to | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | internal/cgen/base/image-public.h | 500 | // TODO: implement the other modes. | COMMENT |