Report Generator Skill

Generate professional markdown and HTML reports from data with charts, tables, and analysis.

Instructions

You are a report generation expert. When invoked:

1. Analyze Data:

• Understand data structure and content
• Identify key metrics and insights
• Calculate statistics and trends
• Detect patterns and anomalies
• Generate executive summaries

1. Create Report Structure:

• Design clear, logical sections
• Create table of contents
• Add executive summary
• Include detailed analysis
• Provide recommendations

1. Generate Visualizations:

• Create tables for structured data
• Generate charts (bar, line, pie, scatter)
• Add badges and indicators
• Include code blocks and examples
• Format numbers and percentages

1. Format Output:

• Generate markdown reports
• Create HTML reports with styling
• Export to PDF
• Add branding and customization
• Ensure responsive design

Usage Examples

@report-generator data.csv
@report-generator --format html
@report-generator --template executive-summary
@report-generator --charts --pdf
@report-generator --compare baseline.json current.json

Report Types

Executive Summary Report

python
def generate_executive_summary(data, title="Executive Summary"):
    """
    Generate high-level executive summary report
    """
    from datetime import datetime

    report = f"""# {title}
**Generated:** {datetime.now().strftime('%B %d, %Y at %I:%M %p')}

---

## Key Highlights

"""

    # Calculate key metrics
    metrics = calculate_key_metrics(data)

    for metric in metrics:
        icon = "✅" if metric['status'] == 'good' else "⚠️" if metric['status'] == 'warning' else "❌"
        report += f"{icon} **{metric['name']}**: {metric['value']}\n"

    report += f"""

---

## Performance Overview

| Metric | Current | Previous | Change |
|--------|---------|----------|--------|
"""

    for metric in metrics:
        if 'previous' in metric:
            change = calculate_change(metric['current'], metric['previous'])
            arrow = "↑" if change > 0 else "↓" if change < 0 else "→"
            color = "green" if change > 0 else "red" if change < 0 else "gray"

            report += f"| {metric['name']} | {metric['current']:,} | {metric['previous']:,} | {arrow} {abs(change):.1f}% |\n"

    report += """

---

## Recommendations

"""

    recommendations = generate_recommendations(metrics)
    for i, rec in enumerate(recommendations, 1):
        priority = rec.get('priority', 'medium')
        emoji = "🔴" if priority == 'high' else "🟡" if priority == 'medium' else "🟢"

        report += f"{i}. {emoji} **{rec['title']}**\n"
        report += f"   {rec['description']}\n\n"

    return report

Data Analysis Report

python
import pandas as pd
import numpy as np
from datetime import datetime

def generate_data_analysis_report(df, title="Data Analysis Report"):
    """
    Generate comprehensive data analysis report
    """

    report = f"""# {title}
**Date:** {datetime.now().strftime('%Y-%m-%d')}
**Dataset:** {len(df):,} rows × {len(df.columns)} columns

---

## Table of Contents
1. [Dataset Overview](#dataset-overview)
2. [Data Quality](#data-quality)
3. [Statistical Summary](#statistical-summary)
4. [Distributions](#distributions)
5. [Correlations](#correlations)
6. [Insights](#insights)

---

## Dataset Overview

### Basic Information
- **Total Rows:** {len(df):,}
- **Total Columns:** {len(df.columns)}
- **Memory Usage:** {df.memory_usage(deep=True).sum() / 1024**2:.2f} MB
- **Duplicate Rows:** {df.duplicated().sum():,}

### Column Information

| Column | Type | Non-Null | Unique | Sample Values |
|--------|------|----------|--------|---------------|
"""

    for col in df.columns:
        dtype = str(df[col].dtype)
        non_null = df[col].count()
        unique = df[col].nunique()
        samples = df[col].dropna().head(3).tolist()
        sample_str = ", ".join(str(s) for s in samples)

        report += f"| {col} | {dtype} | {non_null:,} | {unique:,} | {sample_str} |\n"

    report += """

---

## Data Quality

### Missing Values

"""

    missing = df.isnull().sum()
    if missing.sum() > 0:
        report += "| Column | Missing Count | Missing % |\n"
        report += "|--------|---------------|----------|\n"

        for col in missing[missing > 0].index:
            count = missing[col]
            pct = (count / len(df)) * 100
            report += f"| {col} | {count:,} | {pct:.1f}% |\n"
    else:
        report += "✅ No missing values detected.\n"

    report += "\n### Data Type Issues\n\n"

    # Check for potential type issues
    type_issues = []

    for col in df.select_dtypes(include=['object']):
        # Check if column should be numeric
        try:
            pd.to_numeric(df[col], errors='raise')
            type_issues.append(f"- `{col}` appears to be numeric but stored as string")
        except:
            pass

        # Check if column should be datetime
        try:
            pd.to_datetime(df[col], errors='raise')
            if df[col].str.contains(r'\d{4}-\d{2}-\d{2}').any():
                type_issues.append(f"- `{col}` appears to be datetime but stored as string")
        except:
            pass

    if type_issues:
        report += "\n".join(type_issues) + "\n"
    else:
        report += "✅ No data type issues detected.\n"

    report += """

---

## Statistical Summary

### Numeric Columns

"""

    # Add statistics for numeric columns
    numeric_cols = df.select_dtypes(include=[np.number]).columns

    if len(numeric_cols) > 0:
        stats = df[numeric_cols].describe()
        report += stats.to_markdown() + "\n"

        # Add additional statistics
        report += "\n### Additional Statistics\n\n"
        report += "| Column | Median | Mode | Std Dev | Variance |\n"
        report += "|--------|--------|------|---------|----------|\n"

        for col in numeric_cols:
            median = df[col].median()
            mode = df[col].mode().iloc[0] if not df[col].mode().empty else "N/A"
            std = df[col].std()
            var = df[col].var()

            report += f"| {col} | {median:.2f} | {mode} | {std:.2f} | {var:.2f} |\n"

    report += """

### Categorical Columns

"""

    categorical_cols = df.select_dtypes(include=['object']).columns

    if len(categorical_cols) > 0:
        for col in categorical_cols[:5]:  # Limit to first 5
            report += f"\n#### {col}\n\n"

            value_counts = df[col].value_counts().head(10)

            report += "| Value | Count | Percentage |\n"
            report += "|-------|-------|------------|\n"

            for value, count in value_counts.items():
                pct = (count / len(df)) * 100
                report += f"| {value} | {count:,} | {pct:.1f}% |\n"

    report += """

---

## Distributions

"""

    # Analyze distributions of numeric columns
    for col in numeric_cols[:5]:  # Limit to first 5
        report += f"\n### {col} Distribution\n\n"

        q1 = df[col].quantile(0.25)
        q2 = df[col].quantile(0.50)
        q3 = df[col].quantile(0.75)
        iqr = q3 - q1

        # Detect outliers
        lower_bound = q1 - 1.5 * iqr
        upper_bound = q3 + 1.5 * iqr
        outliers = df[(df[col] < lower_bound) | (df[col] > upper_bound)]

        report += f"""
**Quartiles:**
- Q1 (25%): {q1:.2f}
- Q2 (50%, Median): {q2:.2f}
- Q3 (75%): {q3:.2f}
- IQR: {iqr:.2f}

**Outliers:** {len(outliers)} ({len(outliers)/len(df)*100:.1f}%)
- Lower bound: {lower_bound:.2f}
- Upper bound: {upper_bound:.2f}

"""

    report += """

---

## Correlations

"""

    if len(numeric_cols) > 1:
        corr_matrix = df[numeric_cols].corr()

        report += "\n### Correlation Matrix\n\n"
        report += corr_matrix.to_markdown() + "\n"

        # Find strong correlations
        report += "\n### Strong Correlations (|r| > 0.7)\n\n"

        strong_corr = []
        for i in range(len(corr_matrix.columns)):
            for j in range(i+1, len(corr_matrix.columns)):
                corr_val = corr_matrix.iloc[i, j]
                if abs(corr_val) > 0.7:
                    col1 = corr_matrix.columns[i]
                    col2 = corr_matrix.columns[j]
                    strong_corr.append((col1, col2, corr_val))

        if strong_corr:
            for col1, col2, corr_val in strong_corr:
                direction = "positive" if corr_val > 0 else "negative"
                report += f"- **{col1}** ↔ **{col2}**: {corr_val:.3f} ({direction})\n"
        else:
            report += "No strong correlations found.\n"

    report += """

---

## Insights

"""

    # Generate insights
    insights = generate_insights(df)

    for insight in insights:
        report += f"### {insight['title']}\n\n"
        report += f"{insight['description']}\n\n"

        if 'details' in insight:
            for detail in insight['details']:
                report += f"- {detail}\n"

        report += "\n"

    return report

def generate_insights(df):
    """Generate data insights"""
    insights = []

    # Insight: Completeness
    missing_pct = (df.isnull().sum().sum() / (len(df) * len(df.columns))) * 100

    if missing_pct < 1:
        status = "excellent"
        emoji = "✅"
    elif missing_pct < 5:
        status = "good"
        emoji = "👍"
    else:
        status = "needs attention"
        emoji = "⚠️"

    insights.append({
        "title": f"{emoji} Data Completeness: {status.title()}",
        "description": f"Overall data completeness is {100-missing_pct:.1f}% with {missing_pct:.1f}% missing values.",
        "details": [
            f"Total cells: {len(df) * len(df.columns):,}",
            f"Missing cells: {df.isnull().sum().sum():,}"
        ]
    })

    # Insight: Duplicates
    dup_count = df.duplicated().sum()

    if dup_count > 0:
        insights.append({
            "title": f"⚠️ Duplicate Records Found",
            "description": f"Found {dup_count:,} duplicate rows ({dup_count/len(df)*100:.1f}% of dataset)",
            "details": [
                "Consider removing duplicates for accurate analysis",
                "Review business logic for duplicate handling"
            ]
        })

    return insights

Performance Report

python
def generate_performance_report(metrics, baseline=None):
    """
    Generate performance comparison report
    """

    report = f"""# Performance Report
**Generated:** {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}

---

## Summary

"""

    if baseline:
        report += "### Comparison with Baseline\n\n"

        report += "| Metric | Current | Baseline | Change | Status |\n"
        report += "|--------|---------|----------|--------|--------|\n"

        for metric_name, current_value in metrics.items():
            if metric_name in baseline:
                baseline_value = baseline[metric_name]
                change = ((current_value - baseline_value) / baseline_value) * 100

                if abs(change) < 5:
                    status = "🟢 Stable"
                elif change > 0:
                    status = "🟢 Improved" if is_improvement(metric_name, change) else "🔴 Degraded"
                else:
                    status = "🔴 Degraded" if is_improvement(metric_name, change) else "🟢 Improved"

                report += f"| {metric_name} | {current_value:.2f} | {baseline_value:.2f} | {change:+.1f}% | {status} |\n"

    else:
        report += "### Current Metrics\n\n"

        report += "| Metric | Value | Status |\n"
        report += "|--------|-------|--------|\n"

        for metric_name, value in metrics.items():
            threshold = get_threshold(metric_name)
            status = evaluate_metric(value, threshold)

            report += f"| {metric_name} | {value:.2f} | {status} |\n"

    report += """

---

## Detailed Analysis

"""

    for metric_name, value in metrics.items():
        report += f"### {metric_name}\n\n"

        if baseline and metric_name in baseline:
            baseline_value = baseline[metric_name]
            change = ((value - baseline_value) / baseline_value) * 100

            report += f"- **Current:** {value:.2f}\n"
            report += f"- **Baseline:** {baseline_value:.2f}\n"
            report += f"- **Change:** {change:+.1f}%\n\n"

            if abs(change) > 10:
                report += f"⚠️ Significant change detected. "
                report += "Review recent changes that may have impacted this metric.\n\n"

        else:
            report += f"- **Value:** {value:.2f}\n\n"

    return report

def is_improvement(metric_name, change):
    """Determine if change is improvement based on metric type"""
    # Lower is better for these metrics
    lower_is_better = ['response_time', 'error_rate', 'latency', 'load_time']

    for pattern in lower_is_better:
        if pattern in metric_name.lower():
            return change < 0

    return change > 0

HTML Report Generation

python
def generate_html_report(data, title="Report", template="default"):
    """
    Generate styled HTML report
    """

    # CSS styles
    css = """
    <style>
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            line-height: 1.6;
            color: #333;
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
            background: #f5f5f5;
        }

        .report-container {
            background: white;
            padding: 40px;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        }

        h1 {
            color: #2c3e50;
            border-bottom: 3px solid #3498db;
            padding-bottom: 10px;
        }

        h2 {
            color: #34495e;
            margin-top: 30px;
            border-left: 4px solid #3498db;
            padding-left: 10px;
        }

        h3 {
            color: #7f8c8d;
        }

        table {
            width: 100%;
            border-collapse: collapse;
            margin: 20px 0;
        }

        th {
            background: #3498db;
            color: white;
            padding: 12px;
            text-align: left;
            font-weight: 600;
        }

        td {
            padding: 10px 12px;
            border-bottom: 1px solid #ecf0f1;
        }

        tr:hover {
            background: #f8f9fa;
        }

        .metric-card {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: 20px;
            border-radius: 8px;
            margin: 10px 0;
            box-shadow: 0 4px 6px rgba(0,0,0,0.1);
        }

        .metric-value {
            font-size: 2em;
            font-weight: bold;
        }

        .metric-label {
            font-size: 0.9em;
            opacity: 0.9;
        }

        .badge {
            display: inline-block;
            padding: 4px 12px;
            border-radius: 12px;
            font-size: 0.85em;
            font-weight: 600;
        }

        .badge-success {
            background: #2ecc71;
            color: white;
        }

        .badge-warning {
            background: #f39c12;
            color: white;
        }

        .badge-danger {
            background: #e74c3c;
            color: white;
        }

        .chart-container {
            margin: 30px 0;
            padding: 20px;
            background: #f8f9fa;
            border-radius: 8px;
        }

        code {
            background: #f4f4f4;
            padding: 2px 6px;
            border-radius: 3px;
            font-family: 'Courier New', monospace;
        }

        pre {
            background: #2c3e50;
            color: #ecf0f1;
            padding: 15px;
            border-radius: 5px;
            overflow-x: auto;
        }

        .timestamp {
            color: #7f8c8d;
            font-size: 0.9em;
        }
    </style>
    """

    # Generate HTML content
    html = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>{title}</title>
        {css}
        <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
    </head>
    <body>
        <div class="report-container">
            <h1>{title}</h1>
            <p class="timestamp">Generated: {datetime.now().strftime('%B %d, %Y at %I:%M %p')}</p>

            {generate_html_content(data)}
        </div>
    </body>
    </html>
    """

    return html

def generate_html_content(data):
    """Generate HTML content from data"""

    html = ""

    # Key metrics section
    if 'metrics' in data:
        html += "<h2>Key Metrics</h2>"
        html += '<div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 15px;">'

        for metric in data['metrics']:
            html += f"""
            <div class="metric-card">
                <div class="metric-label">{metric['name']}</div>
                <div class="metric-value">{metric['value']}</div>
            </div>
            """

        html += "</div>"

    # Table data
    if 'table' in data:
        html += "<h2>Data Table</h2>"
        html += generate_html_table(data['table'])

    # Charts
    if 'charts' in data:
        for chart in data['charts']:
            html += f'<h2>{chart["title"]}</h2>'
            html += '<div class="chart-container">'
            html += generate_chart_html(chart)
            html += '</div>'

    return html

def generate_html_table(table_data):
    """Generate HTML table from data"""

    html = "<table>"

    # Header
    if 'headers' in table_data:
        html += "<thead><tr>"
        for header in table_data['headers']:
            html += f"<th>{header}</th>"
        html += "</tr></thead>"

    # Rows
    html += "<tbody>"
    for row in table_data.get('rows', []):
        html += "<tr>"
        for cell in row:
            html += f"<td>{cell}</td>"
        html += "</tr>"
    html += "</tbody>"

    html += "</table>"
    return html

def generate_chart_html(chart_data):
    """Generate Chart.js chart"""

    chart_id = f"chart_{abs(hash(chart_data['title']))}"

    html = f'<canvas id="{chart_id}" width="400" height="200"></canvas>'
    html += f"""
    <script>
        var ctx = document.getElementById('{chart_id}').getContext('2d');
        var chart = new Chart(ctx, {{
            type: '{chart_data.get('type', 'bar')}',
            data: {{
                labels: {chart_data['labels']},
                datasets: [{{
                    label: '{chart_data['title']}',
                    data: {chart_data['data']},
                    backgroundColor: 'rgba(54, 162, 235, 0.5)',
                    borderColor: 'rgba(54, 162, 235, 1)',
                    borderWidth: 2
                }}]
            }},
            options: {{
                responsive: true,
                maintainAspectRatio: true,
                scales: {{
                    y: {{
                        beginAtZero: true
                    }}
                }}
            }}
        }});
    </script>
    """

    return html

Markdown Tables

python
def generate_markdown_table(data, headers=None, alignment=None):
    """
    Generate markdown table from data

    alignment: list of 'left', 'center', 'right'
    """

    if not data:
        return ""

    # Auto-detect headers if not provided
    if headers is None:
        if isinstance(data[0], dict):
            headers = list(data[0].keys())
        else:
            headers = [f"Column {i+1}" for i in range(len(data[0]))]

    # Generate header row
    table = "| " + " | ".join(str(h) for h in headers) + " |\n"

    # Generate alignment row
    if alignment is None:
        alignment = ['left'] * len(headers)

    align_chars = {
        'left': ':--',
        'center': ':-:',
        'right': '--:'
    }

    table += "| " + " | ".join(align_chars.get(a, ':--') for a in alignment) + " |\n"

    # Generate data rows
    for row in data:
        if isinstance(row, dict):
            row_data = [str(row.get(h, '')) for h in headers]
        else:
            row_data = [str(cell) for cell in row]

        table += "| " + " | ".join(row_data) + " |\n"

    return table

# Example usage
data = [
    {"name": "John", "age": 30, "city": "New York"},
    {"name": "Jane", "age": 25, "city": "San Francisco"},
    {"name": "Bob", "age": 35, "city": "Chicago"}
]

table = generate_markdown_table(
    data,
    headers=['Name', 'Age', 'City'],
    alignment=['left', 'right', 'left']
)

Charts and Visualizations

python
import matplotlib.pyplot as plt
import seaborn as sns

def generate_chart(data, chart_type='bar', title='Chart', output='chart.png'):
    """
    Generate chart from data
    """

    plt.figure(figsize=(10, 6))
    plt.style.use('seaborn-v0_8-darkgrid')

    if chart_type == 'bar':
        plt.bar(data['labels'], data['values'])

    elif chart_type == 'line':
        plt.plot(data['labels'], data['values'], marker='o', linewidth=2)

    elif chart_type == 'pie':
        plt.pie(data['values'], labels=data['labels'], autopct='%1.1f%%')

    elif chart_type == 'scatter':
        plt.scatter(data['x'], data['y'], alpha=0.6)

    plt.title(title, fontsize=16, fontweight='bold')
    plt.tight_layout()
    plt.savefig(output, dpi=300, bbox_inches='tight')
    plt.close()

    return output

# For markdown reports
def embed_chart_in_markdown(chart_path, alt_text="Chart"):
    """Generate markdown image embed"""
    return f"![{alt_text}]({chart_path})\n"

PDF Export

python
from markdown import markdown
from weasyprint import HTML

def markdown_to_pdf(markdown_text, output_path='report.pdf', css=None):
    """
    Convert markdown to PDF
    """

    # Convert markdown to HTML
    html_content = markdown(markdown_text, extensions=['tables', 'fenced_code'])

    # Wrap in HTML document
    html_doc = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <style>
            {css if css else get_default_pdf_css()}
        </style>
    </head>
    <body>
        {html_content}
    </body>
    </html>
    """

    # Convert to PDF
    HTML(string=html_doc).write_pdf(output_path)

def get_default_pdf_css():
    """Default CSS for PDF export"""
    return """
        body {
            font-family: Arial, sans-serif;
            line-height: 1.6;
            color: #333;
            max-width: 800px;
            margin: 0 auto;
            padding: 20px;
        }

        h1 {
            color: #2c3e50;
            border-bottom: 2px solid #3498db;
            padding-bottom: 10px;
        }

        table {
            width: 100%;
            border-collapse: collapse;
            margin: 20px 0;
        }

        th, td {
            border: 1px solid #ddd;
            padding: 8px;
            text-align: left;
        }

        th {
            background-color: #3498db;
            color: white;
        }

        code {
            background: #f4f4f4;
            padding: 2px 4px;
            border-radius: 3px;
        }

        pre {
            background: #f4f4f4;
            padding: 10px;
            border-radius: 5px;
            overflow-x: auto;
        }
    """

Report Templates

python
TEMPLATES = {
    'executive': {
        'sections': ['summary', 'key_metrics', 'recommendations'],
        'style': 'concise'
    },
    'technical': {
        'sections': ['overview', 'detailed_analysis', 'code_examples', 'metrics'],
        'style': 'comprehensive'
    },
    'comparison': {
        'sections': ['baseline', 'current', 'differences', 'trends'],
        'style': 'comparative'
    }
}

def generate_from_template(data, template_name='executive'):
    """Generate report from template"""

    template = TEMPLATES.get(template_name, TEMPLATES['executive'])

    report = f"# {template_name.title()} Report\n\n"

    for section in template['sections']:
        report += generate_section(data, section, template['style'])

    return report

Best Practices

1. Structure reports clearly with table of contents
2. Use visual hierarchy (headings, tables, charts)
3. Include timestamps for all reports
4. Add executive summary for long reports
5. Use consistent formatting throughout
6. Include data sources and methodology
7. Add actionable recommendations
8. Use charts for trends, tables for detailed data
9. Export to multiple formats (MD, HTML, PDF)
10. Automate report generation where possible

Notes

• Keep reports focused and actionable
• Use appropriate visualizations for data types
• Include both summary and detailed views
• Version control report templates
• Test PDF export with different data sizes
• Consider accessibility in HTML reports
• Use responsive design for HTML reports
• Cache generated charts for performance