# End-to-End Automated API Version Upgrade with Agent Mode

Source: https://www.youtube.com/watch?v=K60ZWSkZ1Oc
Recap page: https://rapidrecap.app/video/K60ZWSkZ1Oc
Generated: 2026-02-10T23:33:45.189+00:00

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## Quick Overview

Agent Mode successfully reviews an existing OpenAPI specification for an Enterprise Resource Planning (ERP) API, identifies critical breaking changes needed for a major version bump (v1 to v2), generates a detailed migration guide, and automatically creates a fully versioned Postman collection reflecting all V2 specifications.

**Key Points:**
- The agent reviewed the initial OpenAPI specification (v1.0.0) for the ERP API and identified seven categories of critical breaking changes necessary for the v2 upgrade.
- Key breaking changes included URL versioning (changing from /api/ to /api/v2/), property naming normalization (e.g., snake_case to camelCase), and inconsistent response structures that were unified.
- The agent produced two deliverables: a complete OpenAPI specification for v2.0.0 and a detailed V1_TO_V2_MIGRATION_GUIDE.md file.
- The migration guide provided a comprehensive analysis, including impact estimates for migration tasks (e.g., URL path changes estimated at 2-4 hours).
- Upon request, the agent generated a complete Postman collection based on the new v2 OpenAPI spec, which was verified to contain 7 folders and 35 requests, including updated paths like /api/v2/hr/employees.
- The workflow demonstrated that the new Postman collection and the backend mock server routes (which were also updated) were fully aligned with the V2 specification.
- The process concluded with testing the new V2 endpoints in Postman, confirming functionality across modules like Human Resources and Payroll.

![Screenshot at 00:19: The agent displays the initial analysis of breaking changes needed for the API upgrade, detailing issues like naming convention inconsistencies and response structure changes, which forms the basis for the subsequent migration actions.](https://ss.rapidrecap.app/screens/K60ZWSkZ1Oc/00-00-19.jpg)

**Context:** The video demonstrates using Postman's Agent Mode, powered by Claude Sonnet 4.5, to automate the complex process of upgrading an existing API specification (Enterprise Resource Planning API v1) to a new major version (v2). This involves analyzing the differences between specifications, generating necessary documentation like a migration guide, and producing ready-to-use assets such as a Postman collection reflecting the updated API structure.

## Detailed Analysis

The demonstration begins with the agent analyzing the existing Enterprise Resource Planning (ERP) API specification (v1.0.0) via Agent Mode. The agent quickly identifies six major categories of breaking changes required for a version bump, including URL versioning (e.g., changing /api/hr/employees to /api/v2/hr/employees), property naming normalization (e.g., employee_id to employeeId), inconsistent response structures that were unified, missing pagination on list endpoints, authentication security inconsistencies, and the removal of demo endpoints. Following this analysis, the user prompts the agent to fix these issues, produce a v2 spec, and generate a migration guide. The agent successfully creates two deliverables: the 'Enterprise Resource Planning API v2.openapi.yaml' specification and the 'V1_TO_V2_MIGRATION_GUIDE.md'. The migration guide details the critical changes, impact overview (e.g., 35+ endpoints updated), and next steps. Subsequently, the user requests the agent to generate a Postman collection from the new v2 spec, which is created successfully, showing 7 folders and 35 requests structured according to the v2 paths. The video then shows the agent updating the mock backend routes in 'app.py' to align with the new v2 paths and endpoints, ensuring backward compatibility where necessary. Finally, the user tests the newly created collection in Postman, confirming that endpoints like 'GET /api/v2/hr/employees' function correctly with the updated V2 structure, validating the entire automated upgrade process.

### API Version Upgrade Task

- Review v1 spec and fix breaking changes for v2
- Produce v2 spec and V1 to V2 migration guide
- Generate fully updated Postman collection from v2 spec

### Identified Breaking Changes

- URL Versioning change for all endpoints
- Property naming inconsistencies resolved
- Response structure standardized
- Pagination implemented on list endpoints
- Authentication security fixed
- Demo endpoints removed

### Deliverables Created

- Enterprise Resource Planning API v2.openapi.yaml specification
- V1_TO_V2_MIGRATION_GUIDE.md detailing changes and impact

### Postman Collection Generation

- Agent generated a Postman collection from the v2 spec containing 7 folders and 35 requests, including updated paths like /api/v2/hr/employees

### Backend Integration

- Agent updated the mock backend routes in app.py to use the new /api/v2/ routes, ensuring the mock server aligns with the new specification.

### Testing the V2 API

- User tested the generated collection by executing a POST request to Create Employee and a GET request to Get All Employees, both successfully using the v2 paths.

![Screenshot at 00:04: Display of the original OpenAPI specification file open in an editor, showing the structure of the v1 API.](https://ss.rapidrecap.app/screens/K60ZWSkZ1Oc/00-00-04.jpg)
![Screenshot at 00:19: The Agent Mode output pane listing the six major categories of 'Critical Breaking Changes Needed' identified in the v1 spec.](https://ss.rapidrecap.app/screens/K60ZWSkZ1Oc/00-00-19.jpg)
![Screenshot at 00:39: The file explorer showing the two primary outputs generated by the agent: the updated OpenAPI spec \(v2\) and the migration guide file.](https://ss.rapidrecap.app/screens/K60ZWSkZ1Oc/00-00-39.jpg)
![Screenshot at 01:36: Postman interface showing the generated V2 collection structure, highlighting the updated URL path structure, e.g., GET /api/v2/hr/employees.](https://ss.rapidrecap.app/screens/K60ZWSkZ1Oc/00-01-36.jpg)
![Screenshot at 02:16: The Postman request builder tab open for 'Create Employee' \(POST request\) showing the V2 path /api/v2/hr/employees in use, confirming collection generation success.](https://ss.rapidrecap.app/screens/K60ZWSkZ1Oc/00-02-16.jpg)