Overview DocuGen AI uses Jinja2 as its template engine to generate README files. The template system is flexible, allowing you to customize the output format and structure of generated documentation.
Template Engine Architecture The TemplateEngine class (docugen/templates/engine.py:11) manages template rendering:
class TemplateEngine : def __init__ ( self , template_dir : str | Path | None = None ) -> None : base_dir = Path(template_dir) if template_dir else Path( __file__ ).resolve().parent self .environment = Environment( loader = FileSystemLoader( str (base_dir)), autoescape = False , trim_blocks = True , lstrip_blocks = True , )
Configuration Options Option Value Purpose autoescapeFalseAllows raw Markdown output without HTML escaping trim_blocksTrueRemoves newlines after template blocks lstrip_blocksTrueStrips whitespace before blocks for cleaner output
Default Template Structure The default template (default_readme.md.j2) receives three context variables:
# {{ project_name }} > Generated by DocuGen AI. {% if summary %} ## Analysis Summary - Python files scanned: {{ summary["file_count"] }} - Classes detected: {{ summary["class_count"] }} - Top-level functions detected: {{ summary["function_count"] }} - Methods detected: {{ summary["method_count"] }} - Parsing errors: {{ summary["error_count"] }} {% endif %} ## Technical Documentation {{ ai_content }}
Template Context Variables The name of the project being documented
AI-generated technical documentation from Gemini API
Project analysis metrics including:
file_count: Number of Python files scannedclass_count: Total classes foundfunction_count: Top-level functionsmethod_count: Methods within classeserror_count: Parsing errors encountered Creating Custom Templates Step 1: Create Template File Create a new .j2 file in your templates directory:
# 🚀 {{ project_name }} **AI-Powered Documentation** --- ## 📊 Project Statistics {% if summary %} | Metric | Count | |--------|-------| | Files | {{ summary.file_count }} | | Classes | {{ summary.class_count }} | | Functions | {{ summary.function_count }} | | Methods | {{ summary.method_count }} | {% endif %} ## 📖 Documentation {{ ai_content }} --- *Generated on {{ timestamp }}*
Step 2: Use Custom Template from docugen.templates.engine import TemplateEngine engine = TemplateEngine( template_dir = "/path/to/templates" ) output = engine.render( "custom_readme.md.j2" , { "project_name" : "My Project" , "ai_content" : "Documentation content..." , "summary" : { "file_count" : 15 , "class_count" : 8 , "function_count" : 23 , "method_count" : 42 , }, "timestamp" : "2026-03-10" } )
Advanced Customization Adding Custom Filters Extend the Jinja2 environment with custom filters:
from docugen.templates.engine import TemplateEngine engine = TemplateEngine() engine.environment.filters[ 'uppercase' ] = lambda x : x.upper()
Then in your template:
# {{ project_name | uppercase }}
Conditional Sections Add logic-based content rendering:
{% if summary.error_count > 0 %} ## ⚠️ Parsing Warnings This project encountered {{ summary.error_count }} parsing errors. Review the code for syntax issues. {% endif %} {% if summary.class_count > 10 %} ## 🏗️ Complex Architecture This is a large project with {{ summary.class_count }} classes. {% endif %}
Loops and Iteration If you extend the context with additional data:
{% if files %} ## 📁 File Breakdown {% for file in files %} - **{{ file.path }}**: {{ file.line_count }} lines {% endfor %} {% endif %}
Template Best Practices
Keep Templates Simple Templates should focus on structure and formatting. Leave complex logic in Python code.
Use Whitespace Control Leverage trim_blocks and lstrip_blocks to keep generated Markdown clean.
Provide Fallbacks Always use conditional checks ({% if summary %}) for optional data.
Test Thoroughly Test templates with various data scenarios including missing fields and edge cases.
Rendering API The render() method (docugen/templates/engine.py:21) handles template execution:
def render ( self , template_name : str , context : dict[ str , Any]) -> str : template = self .environment.get_template(template_name) rendered = template.render( ** context).strip() return f " { rendered } \n "
The method automatically strips whitespace and ensures the output ends with a single newline.
Common Use Cases Create templates for different documentation formats:
readme.md.j2 - Standard READMEapi_docs.md.j2 - API reference formatchangelog.md.j2 - Change log formatwiki.md.j2 - Wiki-style documentation
Internationalization Create language-specific templates:
# {{ project_name }} > Generado por DocuGen AI. {% if summary %} ## Resumen del Análisis - Archivos Python escaneados: {{ summary.file_count }} - Clases detectadas: {{ summary.class_count }} {% endif %}
Brand Customization Add company branding and style:
# {{ project_name }}  **Developed by Acme Corp** {{ ai_content }} --- © 2026 Acme Corp. All rights reserved.
