# Simulink Explain Missing Coverage

Use this skill when the user asks to summarize, or asks why Simulink Coverage...

- Repository: https://github.com/matlab/simulink-agentic-toolkit (1305 stars)
- Category: Design
- License: see repository
- Last updated: 2026-10-29
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add matlab/simulink-agentic-toolkit --skill simulink-explain-missing-coverage -g -a claude-code -y`
Codex: `npx skills add matlab/simulink-agentic-toolkit --skill simulink-explain-missing-coverage -g -a codex -y`
Cursor: `npx skills add matlab/simulink-agentic-toolkit --skill simulink-explain-missing-coverage -g -a cursor -y`
Gemini CLI: `npx skills add matlab/simulink-agentic-toolkit --skill simulink-explain-missing-coverage -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add matlab/simulink-agentic-toolkit`

## Description

Use this skill when the user asks to summarize, or asks why Simulink Coverage objectives are missing, unsatisfied, or uncovered on a coverage result they already have, why specific decision, condition, MCDC, relational-boundary, or saturation/overflow outcomes weren't exercised, whether uncovered logic is dead code, or how to close the gap (a test, a coverage filter, or a design change). It reads an existing cvdata, .cvt file, sim-with-coverage output, or Simulink Test result; it never runs cvsim to collect coverage.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Explaining Missing Simulink Coverage

Explain *why* coverage objectives are missing on a coverage result the user **already
has**, and *what to do* about each one, across **all** objective types (decision,
condition, MCDC, relational boundary, saturation/overflow, lookup-table execution).
Works from an existing `cvdata` / `cvdatagroup`, a `.cvt` file, a
`Simulink.SimulationOutput` with coverage on, or a Simulink Test result set.

It keeps two questions separate:

- **Is this outcome reachable?**, for decision/condition/MCDC objectives, answered by
  formal proof (SLDV dead-logic detection) joined to the coverage result deterministically.
  A provably-dead outcome is a *fact*.
- **If reachable, why wasn't it tested, and if dead, was that intended?**, answered by
  the agent, reasoning over an input trace (Model Slicer) plus model structure. This is
  judgment, always presented as a recommendation.

**Requires:** MATLAB R2023a+, Simulink Coverage, Simulink Design Verifier (dead-logic
detection), Simulink Check / Model Slicer (input tracing). The skill
**never collects coverage**, it reads a result that already exists. When SLDV or the Model
Slicer is unavailable, the affected step degrades honestly (see Guardrails), never
fabricating evidence.

## When to Use

- User asks **why** an objective, of any metric, or a specific true/false outcome is
  missing, unsatisfied, or uncovered.
- User asks whether uncovered logic is **dead code** (unreachable) or just **untested**.
- User asks **how to close** a coverage gap on a result they already collected, what test
  to add, what to filter, or what to change.
- User needs **audit-ready triage**: provably-dead vs. still-to-test, each traced to its
  inputs.
- User points at an existing coverage artifact and asks to explain it.

## When NOT to Use

The rest: https://github.com/matlab/simulink-agentic-toolkit/blob/HEAD/skills-catalog/verification-validation-and-test/simulink-explain-missing-coverage/SKILL.md