Repository Analysis

serde-rs/json

Strongly typed JSON library for Rust

7.5 Low AI signal View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of serde-rs/json, a Rust project with 5,611 GitHub stars. SynthScan v2.0 examined 24,021 lines of code across 77 source files, recording 191 pattern matches distributed across 2 syntactic categories. The overall adjusted score of 7.5 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).

7.5
Adjusted Score
7.5
Raw Score
100%
Time Factor
2026-07-28
Last Push
5.6K
Stars
Rust
Language
24.0K
Lines of Code
77
Files
191
Pattern Hits
2026-08-02
Scan Date
0.00
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

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.

No multi-scan history yet — run the scanner again to build trend data.

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 0MEDIUM 0LOW 191

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 191 distinct pattern matches across 2 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 Block174 hits · 157 pts
SeverityFileLineSnippetContext
LOWCargo.toml61# Make serde_json::Map use a representation which maintains insertion order.COMMENT
LOWCargo.toml81arbitrary_precision = []COMMENT
LOWsrc/number.rs161 /// Represents the number as f64 if possible. Returns None otherwise.COMMENT
LOWsrc/number.rs221 }COMMENT
LOWsrc/number.rs281COMMENT
LOWsrc/error.rs101 pub fn is_data(&self) -> bool {COMMENT
LOWsrc/error.rs121 /// use std::io::{self, ErrorKind, Read};COMMENT
LOWsrc/error.rs141 /// Err(error) => {COMMENT
LOWsrc/error.rs181 ///COMMENT
LOWsrc/error.rs201 /// }COMMENT
LOWsrc/lib.rs1//! # Serde JSONCOMMENT
LOWsrc/lib.rs21//! There are three common ways that you might find yourself needing to workCOMMENT
LOWsrc/lib.rs41//! representation. This data structure is [`serde_json::Value`][value].COMMENT
LOWsrc/lib.rs61//!COMMENT
LOWsrc/lib.rs81//! println!("Please call {} at the number {}", v["name"], v["phones"][0]);COMMENT
LOWsrc/lib.rs101//! containing a JSON string and its JSON representation is `"John Doe"`.COMMENT
LOWsrc/lib.rs121//! use serde::{Deserialize, Serialize};COMMENT
LOWsrc/lib.rs141//! }"#;COMMENT
LOWsrc/lib.rs161//! automatically interpret the input data as a `Person` and produce informativeCOMMENT
LOWsrc/lib.rs181//!COMMENT
LOWsrc/lib.rs201//! ```COMMENT
LOWsrc/lib.rs221//! "name": full_name,COMMENT
LOWsrc/lib.rs241//!COMMENT
LOWsrc/lib.rs261//!COMMENT
LOWsrc/lib.rs281//! without the rest of the Rust standard library. Disable the default "std"COMMENT
LOWsrc/raw.rs21///COMMENT
LOWsrc/raw.rs41/// #[derive(Deserialize)]COMMENT
LOWsrc/raw.rs61/// let input: Input = serde_json::from_str(input)?;COMMENT
LOWsrc/raw.rs81/// The typical usage of `RawValue` will be in the borrowed form:COMMENT
LOWsrc/raw.rs101///COMMENT
LOWsrc/raw.rs181 /// except that we avoid an allocation and memcpy if both of the followingCOMMENT
LOWsrc/raw.rs201 ///COMMENT
LOWsrc/raw.rs221 /// // SAFETY: `json` was produced by serde_json's own serializer, so it isCOMMENT
LOWsrc/raw.rs241 /// ```COMMENT
LOWsrc/raw.rs281/// Convert a `T` into a boxed `RawValue`.COMMENT
LOWsrc/raw.rs301/// b: u32,COMMENT
LOWsrc/raw.rs321/// This conversion can fail if `T`'s implementation of `Serialize` decides toCOMMENT
LOWsrc/ser.rs1681 /// correctly formatted but unspecified numerical value.COMMENT
LOWsrc/ser.rs1701 ///COMMENT
LOWsrc/ser.rs2181{COMMENT
LOWsrc/de.rs41impl<'de, R> Deserializer<R>COMMENT
LOWsrc/de.rs161 StreamDeserializer {COMMENT
LOWsrc/de.rs181 /// *This method is only available if serde_json is built with theCOMMENT
LOWsrc/de.rs201 /// carefully_drop_nested_arrays(value);COMMENT
LOWsrc/de.rs1561 /// whether the bytes represent a valid UTF-8 string.COMMENT
LOWsrc/de.rs1581 ///COMMENT
LOWsrc/de.rs1601 ///COMMENT
LOWsrc/de.rs1621 /// use serde_bytes::ByteBuf;COMMENT
LOWsrc/de.rs2341///COMMENT
LOWsrc/de.rs2401 /// let de = serde_json::Deserializer::from_slice(data);COMMENT
LOWsrc/de.rs2521///COMMENT
LOWsrc/de.rs2541/// # ExampleCOMMENT
LOWsrc/de.rs2561/// let file = File::open(path)?;COMMENT
LOWsrc/de.rs2581/// ```COMMENT
LOWsrc/de.rs2601/// fn main() {COMMENT
LOWsrc/de.rs2621/// type.COMMENT
LOWsrc/de.rs2641/// fingerprint: String,COMMENT
LOWsrc/de.rs2661/// structure expected by `T`, for example if `T` is a struct type but the inputCOMMENT
LOWsrc/de.rs2681/// #[derive(Deserialize, Debug)]COMMENT
LOWsrc/de.rs2701///COMMENT
114 more matches not shown…
Fake / Example Data17 hits · 22 pts
SeverityFileLineSnippetContext
LOWREADME.md30 "name": "John Doe",CODE
LOWREADME.md94 "name": "John Doe",CODE
LOWREADME.md120the output looks like `Please call "John Doe" at the number "+44 1234567"`. TheCODE
LOWREADME.md122string and its JSON representation is `"John Doe"`. Printing as a plain stringCODE
LOWREADME.md162 "name": "John Doe",CODE
LOWREADME.md222 "name": "John Doe",CODE
LOWREADME.md252let full_name = "John Doe";CODE
LOWsrc/lib.rs8//! "name": "John Doe",COMMENT
LOWsrc/lib.rs69//! "name": "John Doe",COMMENT
LOWsrc/lib.rs99//! above, the output looks like `Please call "John Doe" at the number "+44COMMENT
LOWsrc/lib.rs101//! containing a JSON string and its JSON representation is `"John Doe"`.COMMENT
LOWsrc/lib.rs135//! "name": "John Doe",COMMENT
LOWsrc/lib.rs188//! "name": "John Doe",COMMENT
LOWsrc/lib.rs216//! let full_name = "John Doe";COMMENT
LOWsrc/value/mod.rs14//! "name": "John Doe",COMMENT
LOWsrc/value/mod.rs42//! let full_name = "John Doe";COMMENT
LOWsrc/value/mod.rs68//! "name": "John Doe",COMMENT