How to use Cursor to repeat REST bug reproductions
Cursor reproduced authenticated REST failures using Swagger readiness, JWT tooling and curl; Stevens refined its stored workflow until the fourth bug ran alone.
linkedin.com
Original prompt
Shared by the source author. See source notes for context.
read work-item 1234. The payload for this is 'x' and the endpoint is http://localhost:8080/blah, go fix it
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See placements →What happened
By the fourth service bug, Stevens reports that Cursor reproduced and fixed the issue without intervention; individual bug diffs and root causes are not published.
Reported by Gethin Stevens — LinkedIn articleHow the agent did it
- Stevens supplied a failing payload, local endpoint, expected response and token-acquisition method.
- Cursor restarted the service, checked Swagger readiness, authenticated and reproduced the request with curl.
- It inspected logs and revised the code until the response matched, while the owner improved the stored workflow after failures.
Where a person stepped in
Stevens supplied the reproduction contract and authentication mechanism, refined the workflow after failures and retained the expected-result decision.
Gethin Stevens wanted Cursor Debug Mode to reproduce a service failure itself instead of repeatedly asking him to run the code. He already had the REST endpoint and failing input, but the agent also needed the local address and a way to obtain the service’s custom JWT.
He put the operating procedure in a Markdown file. Cursor checked for an existing process, restarted and compiled the service, then waited for Swagger to return HTTP 200. An MCP server supplied an authentication token. Cursor sent the supplied payload with curl, collected logs and compared the response with the expected result. A failure sent it back through hypotheses, instrumentation and another code change.
The procedure itself needed refinement. When a bug-fixing run hit a problem, Stevens asked Cursor to update the workflow so the next run avoided it. By the fourth service bug, he reports that the loop completed without intervention while he worked in a separate Cursor instance.
The article provides a repeatable execution contract, not public diffs or the exact causes of all four bugs. Stevens supplied authentication, inputs and expected behavior, and corrected the workflow. Its demonstrated result is an owner-reported autonomous reproduction-and-fix loop within that prepared service environment.
Prompt
Original prompt
Source: LinkedIn article · Gethin Stevens
Frequently asked questions
How did Cursor authenticate requests?
An MCP server supplied the custom JWT token required by the service.
What prevented requests before startup completed?
The workflow waited for a successful Swagger HTTP 200 response.
Are the individual bug fixes publicly shown?
No. The article documents the operating loop and reported completion, without public diffs.
More details
About this account
Stevens supplied a failing payload, local endpoint, expected response and token-acquisition method. Cursor restarted the service, checked Swagger readiness, authenticated and reproduced the request with curl.
Original source-provided example prompt, with placeholder work item and endpoint; it is not represented as the literal first bug request. Firsthand workflow and exact date opened. Fourth-bug autonomy is owner-reported. Original prompt excerpt.
Credit: Gethin Stevens — LinkedIn article
Source published 22 Jan 2026
Source checked 14 Oct 2026
Tools and topics
Cursor Debug Mode · curl · JWT authentication MCP · Swagger
bug reproduction · authenticated endpoint · runtime logs
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.