Production-grade engineering skills for AI coding agents.
This report presents the forensic synthetic code analysis of addyosmani/agent-skills, a JavaScript project with 78,099 GitHub stars. SynthScan v2.0 examined 15,632 lines of code across 124 source files, recording 82 pattern matches distributed across 5 syntactic categories. The overall adjusted score of 10.9 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).
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 82 distinct pattern matches across 5 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 |
|---|---|---|---|---|
| MEDIUM | hooks/simplify-ignore.sh | 144 | # ── Stop: restore all files from backup ─────────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore.sh | 176 | # ── PreToolUse Read: filter in-place ────────────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore.sh | 218 | # ── PostToolUse Edit|Write: expand, then re-filter ──────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 49 | # ── Test 1: Single-line block produces exactly one placeholder ──────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 77 | # ── Test 2: Multi-line block ───────────────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 101 | # ── Test 3: Multiple blocks in one file ────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 128 | # ── Test 4: Reason string preserved ────────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 149 | # ── Test 5: Trailing newline preservation ──────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 165 | # ── Test 6: No blocks → return 1 ──────────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 181 | # ── Test 7: Unclosed block emits warning and flushes ───────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 198 | # ── Test 8: Single-line block with reason ──────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 217 | # ── Test 9: HTML comment syntax ────────────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 238 | # ── Test 10: JSON parsing error warning ────────────────────────────────── | COMMENT |
| MEDIUM | hooks/simplify-ignore-test.sh | 244 | # ── Summary ────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 27 | // ─── Config ────────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 78 | // ─── Helpers ───────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 118 | // ─── Validator ─────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 139 | // ── Frontmatter ────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 173 | // ── Exemption guard ────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 187 | // ── Required sections ──────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 199 | // ── Cross-skill references ─────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-skills.js | 210 | // ─── Main ──────────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-commands.js | 26 | // ─── Config ─────────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-commands.js | 45 | // ─── Parsers ────────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-commands.js | 69 | // ─── Loader ─────────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-commands.js | 90 | // ─── Main ───────────────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-commands.js | 113 | // ── Parity check ──────────────────────────────────────────────────────────── | COMMENT |
| MEDIUM | scripts/validate-commands.js | 139 | // ── Description sync check ────────────────────────────────────────────────── | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | skills/debugging-and-error-recovery/SKILL.md | 40 | ### Step 1: Reproduce | COMMENT |
| LOW | skills/debugging-and-error-recovery/SKILL.md | 87 | ### Step 2: Localize | COMMENT |
| LOW | skills/debugging-and-error-recovery/SKILL.md | 111 | ### Step 3: Reduce | COMMENT |
| LOW | skills/debugging-and-error-recovery/SKILL.md | 121 | ### Step 4: Fix the Root Cause | COMMENT |
| LOW | skills/debugging-and-error-recovery/SKILL.md | 138 | ### Step 5: Guard Against Recurrence | COMMENT |
| LOW | skills/debugging-and-error-recovery/SKILL.md | 154 | ### Step 6: Verify End-to-End | COMMENT |
| LOW | skills/test-driven-development/SKILL.md | 35 | ### Step 1: RED — Write a Failing Test | COMMENT |
| LOW | skills/test-driven-development/SKILL.md | 53 | ### Step 2: GREEN — Make It Pass | COMMENT |
| LOW | skills/test-driven-development/SKILL.md | 71 | ### Step 3: REFACTOR — Clean Up | COMMENT |
| LOW⚡ | skills/test-driven-development/SKILL.md | 110 | // Step 1: Write the reproduction test (it should FAIL) | COMMENT |
| LOW⚡ | skills/test-driven-development/SKILL.md | 119 | // Step 2: Fix the bug | COMMENT |
| LOW⚡ | skills/test-driven-development/SKILL.md | 127 | // Step 3: Test passes → bug fixed, regression guarded | COMMENT |
| LOW | skills/planning-and-task-breakdown/SKILL.md | 24 | ### Step 1: Enter Plan Mode | COMMENT |
| LOW | skills/planning-and-task-breakdown/SKILL.md | 35 | ### Step 2: Identify the Dependency Graph | COMMENT |
| LOW | skills/planning-and-task-breakdown/SKILL.md | 57 | ### Step 3: Slice Vertically | COMMENT |
| LOW | skills/planning-and-task-breakdown/SKILL.md | 79 | ### Step 4: Write Tasks | COMMENT |
| LOW | skills/planning-and-task-breakdown/SKILL.md | 106 | ### Step 5: Order and Checkpoint | COMMENT |
| LOW | skills/code-review-and-quality/SKILL.md | 142 | ### Step 1: Understand the Context | COMMENT |
| LOW | skills/code-review-and-quality/SKILL.md | 152 | ### Step 2: Review the Tests First | COMMENT |
| LOW | skills/code-review-and-quality/SKILL.md | 164 | ### Step 3: Review the Implementation | COMMENT |
| LOW | skills/code-review-and-quality/SKILL.md | 177 | ### Step 4: Categorize Findings | COMMENT |
| LOW | skills/code-review-and-quality/SKILL.md | 193 | ### Step 5: Verify the Verification | COMMENT |
| LOW | skills/deprecation-and-migration/SKILL.md | 69 | ### Step 1: Build the Replacement | COMMENT |
| LOW | skills/deprecation-and-migration/SKILL.md | 77 | ### Step 2: Announce and Document | COMMENT |
| LOW | skills/deprecation-and-migration/SKILL.md | 94 | ### Step 3: Migrate Incrementally | COMMENT |
| LOW | skills/deprecation-and-migration/SKILL.md | 108 | ### Step 4: Remove the Old System | COMMENT |
| LOW | skills/interview-me/SKILL.md | 40 | ### Step 1: Hypothesize, with a confidence number | COMMENT |
| LOW | skills/interview-me/SKILL.md | 53 | ### Step 2: Ask one question at a time, each with a guess attached | COMMENT |
| LOW | skills/interview-me/SKILL.md | 79 | ### Step 3: Listen for "want vs. should want" | COMMENT |
| LOW | skills/interview-me/SKILL.md | 94 | ### Step 4: Restate intent in the user's own words | COMMENT |
| LOW | skills/interview-me/SKILL.md | 113 | ### Step 5: Confirm — explicit yes, not "whatever you think" | COMMENT |
| LOW | skills/code-simplification/SKILL.md | 107 | ### Step 1: Understand Before Touching (Chesterton's Fence) | COMMENT |
| LOW | skills/code-simplification/SKILL.md | 123 | ### Step 2: Identify Simplification Opportunities | COMMENT |
| LOW | skills/code-simplification/SKILL.md | 157 | ### Step 3: Apply Changes Incrementally | COMMENT |
| LOW | skills/code-simplification/SKILL.md | 173 | ### Step 4: Verify the Result | COMMENT |
| LOW | skills/doubt-driven-development/SKILL.md | 62 | ### Step 1: CLAIM — Surface what stands | COMMENT |
| LOW | skills/doubt-driven-development/SKILL.md | 75 | ### Step 2: EXTRACT — Smallest reviewable unit | COMMENT |
| LOW | skills/doubt-driven-development/SKILL.md | 85 | ### Step 3: DOUBT — Invoke the fresh-context reviewer | COMMENT |
| LOW | skills/doubt-driven-development/SKILL.md | 168 | ### Step 4: RECONCILE — Fold findings back | COMMENT |
| LOW | skills/doubt-driven-development/SKILL.md | 181 | ### Step 5: STOP — Bounded loop, not recursion | COMMENT |
| LOW | skills/source-driven-development/SKILL.md | 38 | ### Step 1: Detect Stack and Versions | COMMENT |
| LOW | skills/source-driven-development/SKILL.md | 63 | ### Step 2: Fetch Official Documentation | COMMENT |
| LOW | skills/source-driven-development/SKILL.md | 97 | ### Step 3: Implement Following Documented Patterns | COMMENT |
| LOW | skills/source-driven-development/SKILL.md | 122 | ### Step 4: Cite Your Sources | COMMENT |
| LOW | skills/performance-optimization/SKILL.md | 40 | ### Step 1: Measure | COMMENT |
| LOW | skills/performance-optimization/SKILL.md | 99 | ### Step 2: Identify the Bottleneck | COMMENT |
| LOW | skills/performance-optimization/SKILL.md | 121 | ### Step 3: Fix Common Anti-Patterns | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | references/orchestration-patterns.md | 11 | ### 1. Direct invocation (no orchestration) | COMMENT |
| MEDIUM | docs/agents.md | 58 | ## Worked example: valid orchestration | COMMENT |
| MEDIUM | docs/agents.md | 79 | ## Worked example: invalid orchestration (do not build this) | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | hooks/simplify-ignore.sh | 1 | #!/bin/bash | COMMENT |
| LOW | hooks/sdd-cache-post.sh | 1 | #!/bin/bash | COMMENT |
| LOW | hooks/sdd-cache-pre.sh | 1 | #!/bin/bash | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | skills/frontend-ui-engineering/SKILL.md | 128 | | Lorem ipsum-style copy | Placeholder text hides layout problems that real content reveals (length, wrapping, overflow) | CODE |