chore: create infrastructure to support backend function in cy.prompt

[ryanthemanuel]

Additional details

This PR creates an infrastructure to communicate to the backend within the cloud-delivered cy-prompt code. It is modeled after Cypress.backend

Steps to test

How has the user experience changed?

PR Tasks

• Have tests been added/updated?
• Has a PR for user-facing changes been opened in cypress-documentation?
• Have API changes been updated in the type definitions?

[ryanthemanuel]

I also took this opportunity to remove these types. We won't officially add them until we are ready to release the experiment

[cypress]

cypress    Run #62860

Run Properties:   Passed #62860  •  ad3c467bc9: fix test

Project	cypress
Branch Review	ryanm/chore/add-prompt-backend
Run status	Passed #62860
Run duration	18m 48s
Commit	ad3c467bc9: fix test
Committer	Ryan Manuel
View all properties for this run ↗︎

---

Test results
Failures	0
Flaky	10
Pending	1232
Skipped	0
Passing	32187
View all changes introduced in this branch ↗︎

UI Coverage  45.83%
Untested elements	190
Tested elements	165

Accessibility  92.74%
Failed rules	3 critical   9 serious   2 moderate   2 minor
Failed elements	695

[emilyrohrbough]

I'm curious we'd want to introduce so many places in the app where this could diverge vs bundling this logic up in a cloud call that handles what to do as well as telling the app if it should continue with non-cloud logic

Cloud {
   backend (emitEventName: string, eventName, ...args)) {
      if (!cloudService || !cloudService.isSupportedEvent(emitEventName)) {
         return [true, null]
      }

       return [false, cloudService.handleEvent()]
   }
 
}

private baseBackendRequestHandler (emitEventName: string, eventName, ...args) {
    const [isAppBackendRequest, result] = await this.cloud.backend(.....) <-- initialized on start
    if (!isAppBackendRequest) {
       return result
    }

    return new Promise((resolve, reject) => {

    }
)


backend (eventName, ...args) {
    return this.baseBackendRequestHandler('backend:request', eventName, ...args)
  }

[AtofStryker]

@emilyrohrbough makes a good point. Do we know if this is mostly for the experiment to iterate faster with plans to move it later to something a bit more stable

[ryanthemanuel]

This is a good point and I've refactored it a bit to minimize what is necessary on the app providing hooks to be more flexible in the cloud

[AtofStryker]

looks like some of the added tests are failing?

[AtofStryker]

@emilyrohrbough makes a good point. Do we know if this is mostly for the experiment to iterate faster with plans to move it later to something a bit more stable

[mschile]

Maybe I'm missing something, but is this supposed to be Cypress.backend or is the backendRequestNamespace missing from this call?

[ryanthemanuel]

Yeah this should be backendRequestNamespace not eventName. Will update

[ryanthemanuel]

The functionality is right, the name is confusing (wrong)

[ryanthemanuel]

342dd99 (#31803)

[Copilot]

Pull Request Overview

Adds the plumbing for cy.prompt to send and receive backend requests by mirroring Cypress.backend behavior.

• Introduces a new addSocketListeners API in the cy-prompt server types and manager
• Hooks the cy-prompt lifecycle into the main socket server
• Updates driver code with a new backendRequestHandler and refactors the prompt command

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/types/src/config.ts	Removed experimentalPromptCommand from config types
packages/server/lib/socket-base.ts	Dropped old backend:request handler and registered addSocketListeners
packages/server/lib/cloud/cy-prompt/CyPromptManager.ts	Replaced handleBackendRequest with addSocketListeners
packages/driver/src/cypress.ts	Added backendRequestHandler, refactored backend alias
packages/driver/src/cy/commands/prompt/index.ts	Switched to createCyPrompt and improved error messages
packages/app/src/runner/event-manager.ts	Delegated primary-origin socket events to handler

Comments suppressed due to low confidence (5)

packages/types/src/config.ts:33

• The ReceivedCypressOptions type no longer includes experimentalPromptCommand, but code in project-base.ts still checks this flag. Please re-add experimentalPromptCommand to the Pick<> so the flag remains typed.

& Pick<Cypress.ResolvedConfigOptions, 'chromeWebSecurity' | ... | 'justInTimeCompile'>

packages/server/lib/socket-base.ts:455

• The backend:request listener was removed, so any non-prompt backend events will no longer be handled. Consider restoring or rewriting the logic to route backend:request events through the new addSocketListeners hook.

socket.on('backend:request', (eventName: string, ...args) => {

packages/driver/src/cy/commands/prompt/index.ts:21

• [nitpick] Error messages typically start with an uppercase letter. Consider capitalizing the first word for consistency (e.g., Error waiting for cy prompt bundle…).

throw new Error('error waiting for cy prompt bundle to be downloaded and ready')

packages/driver/src/cy/commands/prompt/index.ts:15

• [nitpick] The name initializedModule is vague; consider renaming to initializedCyPromptDriver or similar to clarify its purpose.

let initializedModule: CyPromptDriverDefaultShape | null = null

packages/app/src/runner/event-manager.ts:801

• There's no existing unit test covering handlePrimaryOriginSocketEvent integration. Please add a test to verify that primary-origin backend events are properly forwarded.

Cypress.handlePrimaryOriginSocketEvent(Cypress, 'backend:request')