@Operation annotation for descriptions in Spring Boot - Step-by-Step Execution

Concept Flow - @Operation annotation for descriptions

Write REST Controller Method

↓

Add @Operation Annotation

↓

Set description attribute

↓

Springdoc Reads Annotation

↓

Generate API Documentation with Description

↓

User Views API Docs with Descriptions

This flow shows how adding @Operation with a description to a REST method helps Springdoc generate clear API docs.

Execution Sample

Spring Boot

@RestController
public class MyController {
  @Operation(description = "Get all users")
  @GetMapping("/users")
  public List<User> getUsers() { return List.of(); }
}

A REST method annotated with @Operation to add a description for API documentation.

Execution Table

Step	Action	Annotation Read	Effect
1	Spring Boot starts and scans controllers	No @Operation yet	No description in docs
2	Reads MyController class	Finds @Operation on getUsers()	Captures description 'Get all users'
3	Springdoc builds API docs	Uses description from @Operation	API docs show 'Get all users' for GET /users
4	User opens API docs UI	Description visible	User understands endpoint purpose

💡 API docs generated with descriptions from @Operation annotations

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
description	null	"Get all users"	"Get all users"	"Get all users"

Key Moments - 2 Insights

Why doesn't the description appear if @Operation is missing?

Without @Operation, Springdoc has no description to read, so the docs show no description (see execution_table step 1).

Can @Operation description be changed dynamically?

No, @Operation is a static annotation read at startup (see execution_table step 2), so descriptions are fixed until restart.

Visual Quiz - 3 Questions

Look at the execution table, at which step does Springdoc capture the description?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Check the 'Annotation Read' column in execution_table rows

According to variable_tracker, what is the value of 'description' after step 3?

A "Get all users"

B "No description"

C null

D undefined

💡 Hint

Look at the 'description' row under 'After Step 3' in variable_tracker

If @Operation annotation is removed, what happens to the API docs description?

A API docs fail to generate

B Description remains the same

C Description becomes empty

D Description shows default text

💡 Hint

Refer to key_moments about missing @Operation and execution_table step 1

Concept Snapshot

@Operation annotation adds descriptions to REST methods.
Place it above controller methods.
Springdoc reads it at startup.
Descriptions appear in generated API docs.
No annotation means no description shown.

Full Transcript

This visual trace shows how the @Operation annotation in Spring Boot REST controllers adds descriptions for API documentation. First, the REST method is written, then @Operation with a description is added. When Spring Boot starts, it scans the controller and reads the @Operation annotation. Springdoc captures the description and uses it to generate API docs. When users open the docs, they see the description explaining the endpoint. Variables like 'description' start as null and get set when the annotation is read. If @Operation is missing, no description appears. This helps beginners understand how adding @Operation improves API docs clarity.