How to test PR user workflows with Unknown
Canary generates and runs user-flow tests from code and pull-request changes, then posts results and recordings. Its founders reported catching an invoice discrepancy before release.
news.ycombinator.comPrompt to try
Editorial adaptation, not the source author’s exact prompt. Replace bracketed inputs and review tool permissions first.
Test [pull request] against [preview application]. Read the codebase and diff, identify affected user workflows, generate and run end-to-end tests, and report unexpected behavior with results and recordings on the pull request.
Reach people exploring AI agents
See placements →What happened
The founders reported catching an invoicing regression before release, with an amount-due discrepancy of approximately $1,600.
Reported by Visweshyc on Hacker NewsHow the agent did it
- Connect Canary to the codebase to examine application structure.
- Push a pull request for Canary to read and analyze.
- Generate and execute affected workflow tests against the preview app.
Where a person stepped in
The post describes PR results and recordings but does not describe the customer’s human review or repair steps.
A person set the goal and reviewed the result.
Canary's founders described an AI QA system that reads an application's codebase and tests user behavior affected by pull requests. It connects to the repository and examines routes, controllers, and validation logic. When a pull request is pushed, it reads the diff, interprets the intended changes, and generates tests for affected workflows.
Those tests run against the preview application, checking user flows end to end. Canary comments on the pull request with results and recordings, highlighting behavior that does not match expectations. The founders also described triggering specific workflow tests through pull-request comments. Tests generated from a pull request can be moved into regression suites, and plain-English requests can generate suites that run on a schedule.
The concrete customer example involved a construction-technology company's invoicing flow. The amount due drifted from the original proposal total by approximately $1,600. The founders said Canary caught that regression before release. The post does not describe the customer's exact prompt, the individual test actions, or the subsequent repair. Its broader workflow explains how the product tests changes and surfaces findings for review.
Who it's for: Teams that deploy preview applications and want automated checks of user workflows affected by code changes.
Prompt
Suggested prompt (written by Agents In Use, not the author's)
Source: Hacker News · Visweshyc
Frequently asked questions
Where does Canary run generated PR tests?
The founders say it runs tests against the preview application and comments on the pull request with results and recordings.
What customer regression did Canary catch?
The founders reported an invoicing flow where the amount due differed from the original proposal total by about $1,600. Canary caught it before release.
More details
Remaining steps
- Post test results and recordings on the pull request.
About this account
Canary analyzes code changes, generates workflow tests, executes them, and reports results on the pull request.
Platform: Hacker News. Attribution: https://news.ycombinator.com/item?id=47441629. Prompt: Suggested (written by Agents In Use, not the author's). Sourced by the Agents In Use pipeline.
Credit: Visweshyc on Hacker News
Source published 19 Mar 2026
Source checked 14 Oct 2026
Tools and topics
Canary · Pull requests · Preview application
Software development
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.