# Documenting Features for Developers

Code alone rarely explains a feature well enough to extend it or debug it quickly. Even when it does, understanding it through code only can take unnecessary time and effort. Good documentation can help tremendously.

**Write as if the reader never attended design meetings, never read the implementation tickets, or even never used the feature.** The goal is to make them productive fast.

What to include:

1. What the feature does, its benefits and the problems it addresses
    
2. How to use it locally
    

* application settings to enable
    
* if any third-party service is required, how to set it up and get its credentials
    
* data to create or seed
    
* exact steps to follow to use the feature
    
* expected results
    

**This section is critical.** Developers often spend more time figuring out how to use a feature than fixing the bug itself.

3. How it is designed and how it works
    

Describe the architecture and the reasoning behind it:

* key components and data flow
    
* links to important classes, modules, and methods
    
* trade-offs, rejected alternatives, known limitations
    

4. Troubleshooting
    

Provide a practical playbook:

* typical symptoms
    
* likely causes: internal services, external APIs, configuration issues, end-users misunderstandings...
    
* logs to check and where to find them
    
* relevant metrics and dashboards
    
* concrete steps to confirm and fix
    

5. Maintenance
    

Document recurring tasks:

* upgrades (libraries, services, dependencies)
    
* checks to perform after upgrades
    
* anything that requires periodic attention
    

6. References
    

Link to useful resources:

* external APIs
    
* original design documents
    
* related tickets, tests, diagrams, specs
    

and link to the doc from the relevant pieces of code to make it more discoverable.

Finally, treat documentation as code: keep it in the repository, version it, and review it in every PR. This "Docs-as-Code" approach prevents knowledge rot and provides AI tools with the context they need to better support development.