Matlab Review Code

---
name: matlab-review-code
description: Review MATLAB code for quality, performance, maintainability, and adherence to MathWorks coding standards. Uses check_matlab_code and matlab_coding_guidelines. Use when reviewing code, checking style, finding code smells, assessing quality, or preparing code for handoff or publication.
license: https://www.mathworks.com/content/dam/mathworks/license/pmrl/license.md
metadata:
  author: MathWorks
  version: "1.1"
---

# Code Review

Systematically review MATLAB code for quality, correctness, performance, and adherence to MathWorks coding conventions using static analysis and manual inspection patterns.

## When to Use

- User asks to review, audit, or improve code quality
- User wants to check adherence to MathWorks coding standards
- Preparing code for handoff, publication, or open-source release
- After a significant implementation — verify before committing
- User reports "code smells" or asks for cleanup suggestions

## When NOT to Use

- User wants to debug a runtime error — use `matlab-debug-code` instead
- User wants to optimize performance — use performance profiling skills
- User wants to generate tests — use `matlab-write-tests` instead

## Workflow

1. **Run static analysis** — Use `check_matlab_code` MCP tool on all target files
2. **Load coding standards** — Read the `matlab_coding_guidelines` MCP resource
3. **Check naming** — Verify functions, classes, variables, and files follow conventions
4. **Review function signatures** — Arguments blocks, input/output counts, name-value patterns
5. **Assess structure** — Function length, nesting depth, complexity
6. **Check patterns** — Vectorization, preallocation, modern API usage
7. **Summarize** — Report findings by severity: errors > warnings > suggestions

## Step 1: Static Analysis

Use the `check_matlab_code` MCP tool on each file. Then inspect results programmatically:

```matlab
info = checkcode("src/computeArea.m", "-struct");
for k = 1:numel(info)
    fprintf('Line %d (col %d-%d): %s\n', ...
        info(k).line, info(k).column(1), info(k).column(end), info(k).message);
end
```

For directory-wide analysis (R2022b+):

```matlab
issues = codeIssues("src");
disp(issues.Issues);
```

## Step 2: Load Coding Standards

Read the `matlab_coding_guidelines` MCP resource to get the authoritative MathWorks coding standards. Use these as the baseline for all naming, formatting, and structural checks.

## Review Checklist

### Naming

| Element | Convention | Example |
|---------|-----------|---------|
| Functions | lowerCamelCase, verb phrase | `computeArea`, `loadData` |
| Classes | PascalCase | `SensorReader`, `DataProcessor` |
| Variables | lowerCamelCase, descriptive | `sampleRate` not `sr` |
| Constants | UPPER_SNAKE or `Constant` property | `MAX_ITERATIONS` |
| Test files | `t` prefix | `tComputeArea.m` |
| App files | PascalCase | `DashboardApp.m` |
| File = function | File name matches primary function | `computeArea.m` → `function computeArea` |

### Function Quality

| Check | Standard | Severity |
|-------|----------|----------|
| Input count | Max 6 positional inputs | Warning |
| Output count | Max 4 outputs | Warning |
| Validation | `arguments` block present | Warning |
| Name-value args | `options.Name` pattern (not `varargin`) | Suggestion |
| Length | Flag if >50 lines | Suggestion |
| Nesting | Flag if >3 levels deep | Warning |
| `end` keyword | All functions terminated with `end` | Warning |
| Help text | H1 line present for public functions | Suggestion |

### Code Patterns

| Check | Modern | Legacy (flag it) |
|-------|--------|-------------------|
| Multi-panel figures | `tiledlayout`/`nexttile` | `subplot` |
| Date/time | `datetime` | `datenum`/`datestr` |
| Strings | `string` type | char arrays for text |
| Vectorization | `.*`, `./`, logical indexing | Loops over elements |
| Preallocation | `zeros(n,1)` before loop | Growing arrays in loops |
| Data containers | `table`/`timetable` | Raw matrices for named data |
| Dynamic eval | Direct function calls | `eval`, `evalin`, `assignin` |

### High-Severity Flags

These should always be reported as errors:

- Use of `eval`, `assignin`, or `evalin` — security and maintainability risk
- Growing arrays inside loops without preallocation — performance
- Shadowing built-in functions — `sum = 5` shadows `sum()`
- Missing `arguments` block in public-facing functions
- Hardcoded file paths with backslashes

### What checkcode Misses

`check_matlab_code` does NOT catch all issues. After running static analysis, **always scan the source code** for these common problems that require visual inspection:

- **`subplot` usage** — not flagged by checkcode, but should use `tiledlayout`/`nexttile`
- **Shadowed builtin variables** — `sum = 0` shadows `sum()`, checkcode may not flag it
- **Deep nesting** (>3 levels) — checkcode does not measure nesting depth
- **Hardcoded backslash paths** — checkcode flags unused variables but not path style
- **Magic numbers** — unlabeled constants in code (e.g., `if length(x) > 10`)
- **Missing H1 help text** — checkcode does not require help text

Do not skip Steps 3-6 of the workflow just because checkcode returns few results.

## Patterns

### Complexity Assessment

```matlab
function complexity = assessComplexity(filePath)
%assessComplexity Estimate cyclomatic complexity of a MATLAB function.

    arguments
        filePath (1,1) string {mustBeFile}
    end

    code = fileread(filePath);
    branchKeywords = ["if " "elseif " "case " "while " "for " "catch "];
    complexity = 1;
    for kw = branchKeywords
        complexity = complexity + numel(strfind(code, kw));
    end
end
```

### Check Toolbox Dependencies

```matlab
[files, products] = matlab.codetools.requiredFilesAndProducts('src/myFunction.m');
fprintf('Required products:\n');
for k = 1:numel(products)
    fprintf('  %s (ID: %d)\n', products(k).Name, products(k).ProductNumber);
end
```

### Review Report Format

Present findings in this format:

```
## Code Review: computeArea.m

### Static Analysis (checkcode)
- 2 warnings, 0 errors

### Naming ✓
- [x] Function: lowerCamelCase
- [x] Variables: descriptive
- [x] File name matches function

### Structure
- [x] arguments block present
- [x] Function under 50 lines
- [ ] ⚠ Nesting depth reaches 4 levels (line 32)

### Patterns
- [x] Vectorized
- [x] Modern graphics API
- [ ] ⚠ Uses datenum (line 18) — migrate to datetime

### Suggestions
1. Extract nested logic at line 32 into a local function
2. Replace datenum with datetime for date handling
```

## Conventions

- Always run `check_matlab_code` as the first step — it catches issues automatically
- Load `matlab_coding_guidelines` for the authoritative standard
- Report findings by severity: errors (must fix) > warnings (should fix) > suggestions (nice to have)
- Flag any use of `eval`, `assignin`, or `evalin` as high-severity
- Check `requiredFilesAndProducts` to verify toolbox dependencies are documented
- Verify every public function has an H1 help text line
- Use `codeIssues` for directory-wide analysis (R2022b+)
- Do not suggest changes that alter behavior — review is read-only assessment
- For deprecated API migration details, use the `matlab-modernize-code` skill

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Copyright 2026 The MathWorks, Inc.

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