A Git-compatible VCS that is both simple and powerful
This report presents the forensic synthetic code analysis of jj-vcs/jj, a Rust project with 30,339 GitHub stars. SynthScan v2.0 examined 303,415 lines of code across 636 source files, recording 811 pattern matches distributed across 10 syntactic categories. The overall adjusted score of 2.8 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).
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.
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 811 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.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | deny.toml | 1 | # This template contains all of the possible sections and their default values | COMMENT |
| LOW | deny.toml | 21 | # `target_family = "unix"` configuration, that only having windows targets in | COMMENT |
| LOW | deny.toml | 41 | #exclude = [] | COMMENT |
| LOW | deny.toml | 61 | COMMENT | |
| LOW | deny.toml | 101 | ] | COMMENT |
| LOW | deny.toml | 121 | # The SPDX expression for the license requirements of the crate | COMMENT |
| LOW | deny.toml | 141 | # not have its license(s) checked | COMMENT |
| LOW | deny.toml | 161 | # the workspace that is being checked. This can be overridden by allowing/denying | COMMENT |
| LOW | deny.toml | 181 | COMMENT | |
| LOW | deny.toml | 201 | # If true, the allowed features must exactly match the enabled feature set. If | COMMENT |
| LOW | deny.toml | 221 | # https://embarkstudios.github.io/cargo-deny/checks/sources/cfg.html | COMMENT |
| LOW | web/docs/src/content/docs/config.toml | 21 | COMMENT | |
| LOW | docs/config.toml | 21 | COMMENT | |
| LOW | cli/build.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_file_search_command.rs | 1 | // Copyright 2025 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_git_init.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_git_colocation.rs | 1 | // Copyright 2025 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_immutable_commits.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_run_command.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_file_list_command.rs | 1 | // Copyright 2025 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_config_schema.rs | 1 | // Copyright 2025 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_util_command.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_bisect_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_fix_command.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_resolve_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_git_root.rs | 1 | // Copyright 2025 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_revset_output.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_debug_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_commit_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_interdiff_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_squash_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_git_push.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_git_push.rs | 2401 | [EOF] | COMMENT |
| LOW | cli/tests/test_fileset_output.rs | 1 | // Copyright 2026 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_next_prev_commands.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_concurrent_operations.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_restore_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_operations.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_absorb_command.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_builtin_aliases.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_parallelize_command.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_evolog_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_workspaces.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_gitignores.rs | 1 | // Copyright 2020 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_git_clone.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_config_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_metaedit_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_working_copy.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_templater.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_split_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_advance_bookmarks.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_rebase_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_show_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_diffedit_command.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_global_opts.rs | 1 | // Copyright 2022 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_generate_md_cli_help.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_duplicate_command.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_arrange_command.rs | 1 | // Copyright 2026 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_tag_command.rs | 1 | // Copyright 2024 The Jujutsu Authors | COMMENT |
| LOW | cli/tests/test_file_chmod_command.rs | 1 | // Copyright 2023 The Jujutsu Authors | COMMENT |
| 707 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | web/docs/src/content/docs/config.md | 2009 | email = "YOUR_OSS_EMAIL@example.org" | STRING |
| LOW | web/docs/src/content/docs/revsets.md | 549 | 'user()' = 'user("me@example.org")' | CODE |
| LOW | docs/config.md | 2335 | email = "YOUR_OSS_EMAIL@example.org" | STRING |
| LOW | docs/revsets.md | 586 | 'user()' = 'user("me@example.org")' | CODE |
| LOW | cli/tests/test_git_init.rs | 1150 | user.email = 'base@example.org' | CODE |
| LOW | cli/tests/test_git_init.rs | 1155 | user.email = 'new-repo@example.org' | CODE |
| LOW | cli/tests/test_git_clone.rs | 963 | user.email = 'base@example.org' | CODE |
| LOW | cli/tests/test_git_clone.rs | 968 | user.email = 'new-repo@example.org' | CODE |
| LOW | cli/src/text_util.rs | 663 | split_email("user@example.com"), | CODE |
| LOW | cli/src/config.rs | 1124 | assert_eq!(parse("John Doe")?.as_str(), Some("John Doe")); | CODE |
| LOW | cli/src/template_builder.rs | 3876 | literal(new_signature("User", "user@example.com")) | CODE |
| LOW | cli/src/template_builder.rs | 4015 | literal(new_signature("User", "user@example.com")) | CODE |
| LOW | cli/src/template_builder.rs | 5607 | literal(new_signature("User", "user@example.com")) | CODE |
| LOW | cli/src/config/colors.toml | 40 | "placeholder" = "red" | CODE |
| LOW | lib/testutils/src/git.rs | 21 | pub const GIT_EMAIL: &str = "someone@example.org"; | CODE |
| LOW | lib/src/trailer.rs | 49 | /// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod | COMMENT |
| LOW | lib/src/trailer.rs | 49 | /// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod | COMMENT |
| LOW | lib/src/trailer.rs | 151 | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed | CODE |
| LOW | lib/src/trailer.rs | 151 | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed | CODE |
| LOW | lib/src/trailer.rs | 184 | Summary: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod | CODE |
| LOW | lib/src/trailer.rs | 184 | Summary: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| CRITICAL | cli/src/commit_ref_list.rs | 498 | .map(|c| c.author.timestamp.timestamp.0.to_string()) | CODE |
| CRITICAL | cli/src/commit_ref_list.rs | 508 | .map(|c| c.committer.timestamp.timestamp.0.to_string()) | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| HIGH | web/docs/src/content/docs/config.md | 0 | /// set -euo pipefail /// echo "look ma, everything in one file!" /// echo "args: $@" /// | STRING |
| HIGH | docs/config.md | 0 | /// set -euo pipefail /// echo "look ma, everything in one file!" /// echo "args: $@" /// | STRING |
| HIGH | cli/src/commands/util/exec.rs | 0 | /// set -euo pipefail /// echo "look ma, everything in one file!" /// echo "args: $@" /// | STRING |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | web/docs/src/content/docs/FAQ.md | 332 | #### Step 1: Find the commit ID for the "last good version" | COMMENT |
| LOW | web/docs/src/content/docs/FAQ.md | 414 | #### Step 2: Create a new change on top of the original revision | COMMENT |
| LOW | web/docs/src/content/docs/FAQ.md | 455 | #### Step 3: Move any bookmarks to the original revision | COMMENT |
| LOW | web/docs/src/content/docs/FAQ.md | 461 | #### Step 4: Abandon the unwanted revision | COMMENT |
| LOW | docs/FAQ.md | 331 | #### Step 1: Find the commit ID for the "last good version" | COMMENT |
| LOW | docs/FAQ.md | 415 | #### Step 2: Create a new change on top of the original revision | COMMENT |
| LOW | docs/FAQ.md | 459 | #### Step 3: Move any bookmarks to the original revision | COMMENT |
| LOW | docs/FAQ.md | 465 | #### Step 4: Abandon the unwanted revision | COMMENT |
| LOW | lib/src/graph_dominators.rs | 281 | // Step 1: Compute Dominators on Reverse Graph | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | cli/tests/test_global_opts.rs | 1344 | // The timestamp is constant sized so this is a robust operation. | COMMENT |
| MEDIUM | cli/src/cli_util.rs | 904 | // TODO: bump MSRV to 1.91.0 to leverage const PathBuf::new() | COMMENT |
| MEDIUM | lib/src/secure_config.rs | 306 | // In the future, we consider something a little more robust, where as | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | web/docs/src/content/docs/config.toml | 3 | # Don't forget to change these to your own details! | COMMENT |
| LOW | docs/config.toml | 3 | # Don't forget to change these to your own details! | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | lib/src/graph_dominators.rs | 281 | // Step 1: Compute Dominators on Reverse Graph | COMMENT |
| LOW | lib/src/git.rs | 476 | // a tag or not, and we need to check if it's a commit object. | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | lib/src/secure_config.rs | 43 | # This file is for old versions of jj. | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | lib/tests/test_merge_trees.rs | 116 | // TODO: Add tests for simplification of multi-way conflicts. Both the content | COMMENT |