Use when asked to run Design Error Detection (quick defect scan), find design errors in a Simulink model, perform root cause analysis on DED findings, fix division-by-zero, overflow, dead logic or out-of-bounds defects detected by SLDV, or diagnose why missing coverage cannot be achieved (dead logic blocking coverage objectives).
SkillScore78Maintained
Automatic
◆Coding pack
Last verified 8/17/2026
What it changes
Passed 14 of 18 test cases with the skill, and 5 of 18 without it.
Without skill26%
With skill78%
Checks it passed that the model alone missed
Classifies the finding as design_error
Loads references/fix-strategy.md for guidance
Passes DataFile set to the saved .mat file path
and 14 more in the full report
13 fixed5 passed either way4 still failing1 broke
Pass-rate lift
+52 pp
Tokens
+49%
Agent turns
0%
Response time
-54%
Model gemini-3.6-flashMeasured 8/17/2026v218 of 23 cases passed with skill · 18 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 13 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 13
Prompt
You need to analyze root causes for `YawController.slx` using existing artifacts stored in `artifacts/yaw_sldvdata.mat`. Which parameter is used to pass this file to `sldv_find_de_root_cause`?
What was checked, without and with the skill
Checked
Without skill
With skill
Passes DataFile set to the saved .mat file path
Missed
Passed
case-22 · gemini-3.6-flash · 8/17/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md154 lines27 filesincludes scripts
Detecting Design Errors (SLDV DED + Root Cause Analysis)
When to Use
User asks to check a Simulink model for design errors (division-by-zero, overflow, dead logic, out-of-bounds)
User asks to find root causes of DED findings
User asks to fix or understand an analysis finding
User asks why there is missing coverage due to dead logic (dead logic gates prevent coverage objectives from being satisfied)
User has SLDV artifacts (.mat file) and wants analysis without re-running DED
When NOT to Use
Requirement verification — checking if a model satisfies a requirement
Test generation or test authoring — creating test cases from requirements or for coverage
Comprehensive verification — this skill is a quick defect scan, not an exhaustive proof; a clean result does not guarantee the model is free of all errors
Coverage measurement — this skill does not measure or report model coverage; use Simulink Coverage tools
Safety Rules
Never patch the original model directly. Always clone first before applying any fix.
NEVER apply fixes without explicit user approval. After root cause analysis, present findings and suggest a fix strategy — then STOP and wait for the user to say "yes, apply it" or "go ahead." Even if the user's prompt says "suggest a fix" or "fix it," you must present the plan first and wait for confirmation. Do NOT create clone models, set parameters, or run verification until the user explicitly approves.
SLDV results are always sound. Never assume SLDV returns false positives. If SLDV reports a defect, it is a real defect — treat every finding as a true positive and investigate accordingly.
All script functions live in the skill's scripts/ directory. Use evaluate_matlab_code with project_path set to that folder so MATLAB can find them.
Workflow
This skill provides two functions that automate SLDV-driven analysis the agent otherwise gets
wrong when hand-rolling it, then hands you the facts to classify and fix findings. The workflow
is four steps:
1. Detect errors → sldv_run_defect_checker (use the function; don't hand-roll DED)
2. Root cause errors → sldv_find_de_root_cause (use the function; don't hand-roll slicing)