render-template

name	render-template
description	Render templates with variable substitution using {{variable}} or ${variable} syntax. Use for generating formatted output, reports, commit messages, or any text requiring variable interpolation.

Render Template

Render templates with variable substitution, supporting various syntax formats and helper functions.

When to Use

• Format commit messages with dynamic data
• Generate report sections with variables
• Create formatted outputs from templates
• Replace placeholders in text templates
• Consolidate formatting logic across Skills

Instructions

Step 1: Receive Template and Data

Accept template string and variable data.

Expected Input:

• template: String (template with placeholders)
• variables: Object (key-value pairs for substitution)
• syntax: String (optional: mustache|shell|mixed, default: mustache)

Supported Syntax:

• Mustache: {{variable}}, {{object.property}}
• Shell: ${variable}, ${VARIABLE}
• Mixed: Supports both

Step 2: Parse Template

Identify all placeholders in template.

Placeholder Patterns:

• {{variable}}: Simple variable
• {{object.property}}: Nested property
• {{#if condition}}...{{/if}}: Conditional (optional)
• {{#each array}}...{{/each}}: Loop (optional)

Step 3: Resolve Variables

Replace placeholders with values from variables object.

Resolution Rules:

• Direct match: {{name}} → variables.name
• Nested property: {{user.name}} → variables.user.name
• Missing variable: Replace with empty string or keep placeholder (configurable)
• Undefined: Replace with empty string

Step 4: Apply Filters (Optional)

Support simple filters if specified.

Common Filters:

• {{variable | uppercase}}: Convert to uppercase
• {{variable | lowercase}}: Convert to lowercase
• {{variable | capitalize}}: Capitalize first letter
• {{date | format:YYYY-MM-DD}}: Format date

Step 5: Return Rendered Output

Return final rendered string.

Expected Output: String (template with variables replaced)

Error Handling

• Missing Variables: Replace with empty string or warn (configurable)
• Invalid Template Syntax: Return error describing syntax issue
• Circular References: Detect and return error
• Type Mismatch: Convert to string automatically

Examples

Example 1: Simple Variable Substitution

Input:

{
  "template": "Hello {{name}}, your score is {{score}}!",
  "variables": {
    "name": "Alice",
    "score": 95
  },
  "syntax": "mustache"
}

Output:

Hello Alice, your score is 95!

Example 2: Nested Properties

Input:

{
  "template": "User: {{user.name}} ({{user.email}})\nRole: {{user.role}}",
  "variables": {
    "user": {
      "name": "Bob",
      "email": "[e-mail]",
      "role": "admin"
    }
  }
}

Output:

User: Bob ([e-mail])
Role: admin

Example 3: Shell Syntax

Input:

{
  "template": "Version: ${VERSION}\nDate: ${RELEASE_DATE}",
  "variables": {
    "VERSION": "0.8.0",
    "RELEASE_DATE": "2025-10-17"
  },
  "syntax": "shell"
}

Output:

Version: 0.8.0
Date: 2025-10-17

Example 4: Commit Message Template

Input:

{
  "template": "{{type}}({{scope}}): {{description}}\n\n{{body}}\n\n🤖 Generated with Codex\nCo-Authored-By: Codex <[e-mail]>",
  "variables": {
    "type": "feat",
    "scope": "auth",
    "description": "add OAuth2 support",
    "body": "Implemented OAuth2 flow with token refresh.\nSupports Google and GitHub providers."
  }
}

Output:

feat(auth): add OAuth2 support

Implemented OAuth2 flow with token refresh.
Supports Google and GitHub providers.

🤖 Generated with Codex
Co-Authored-By: Codex <[e-mail]>

Example 5: Missing Variables

Input:

{
  "template": "Name: {{name}}\nAge: {{age}}\nCity: {{city}}",
  "variables": {
    "name": "Alice"
  }
}

Output (with empty string replacement):

Name: Alice
Age:
City:

Output (with keep placeholder):

Name: Alice
Age: {{age}}
City: {{city}}

Example 6: Report Header Template

Input:

{
  "template": "# {{reportType}} Report: {{version}}\n\n**Generated**: {{timestamp}}\n**Status**: {{statusEmoji}} {{status}}\n**Version**: {{version}}",
  "variables": {
    "reportType": "Bug Hunting",
    "version": "2025-10-17",
    "timestamp": "2025-10-17 14:30:00 UTC",
    "statusEmoji": "✅",
    "status": "success"
  }
}

Output:

# Bug Hunting Report: 2025-10-17

**Generated**: 2025-10-17 14:30:00 UTC
**Status**: ✅ success
**Version**: 2025-10-17

Validation

• Replaces simple variables correctly
• Handles nested properties
• Supports multiple syntax formats
• Handles missing variables gracefully
• Converts types to strings
• Preserves formatting (line breaks, indentation)
• Detects circular references
• Returns clear error messages

Supporting Files

None required - pure template rendering logic.

Integration with Other Skills

This Skill consolidates formatting logic used by:

• format-commit-message: Use render-template for message formatting
• generate-report-header: Use render-template for header generation
• format-todo-list: Use render-template for activeForm generation
• generate-changelog: Use render-template for section formatting

Example Integration:

Instead of: Hard-coded string formatting in each Skill
Use: render-template Skill with predefined templates
Result: Consistent formatting, easier to maintain