[fix]: make `page.evaluate()` use main world #1331

seanmcguire12 · 2025-12-02T00:47:09Z

why

currently, we add the init scripts to the main world
this is problematic, because page.evaluate() uses the v3-world
this means that you can't easily evaluate the script you add with addInitScript()

what changed

makes sure that page.evaluate() uses the main world

test plan

added a test which calls page.evaluate() on a script added via context.addInitScript()

Summary by cubic

Fixes a context mismatch: page.evaluate now runs in the main world so scripts injected via context.addInitScript are callable. Frame.evaluate was updated to use the main world too.

Why:

evaluate() used the v3 isolated world while init scripts were in the main world, making injected globals inaccessible.

What:

Switched page.evaluate and frame.evaluate to use the main-world execution context via executionContextRegistry.
Added a test verifying an init-script function is callable from page.evaluate.

Test Plan:

New test: init-script function is callable from page.evaluate (passes).
Ran existing context.addInitScript tests to ensure no regressions.

^{Written for commit d4bf59d. Summary will update automatically on new commits.}

changeset-bot · 2025-12-02T00:47:12Z

🦋 Changeset detected

Latest commit: d4bf59d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@browserbasehq/stagehand	Patch
@browserbasehq/stagehand-evals	Patch

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greptile-apps · 2025-12-02T00:49:32Z

Greptile Overview

Greptile Summary

Changed page.evaluate() and frame.evaluate() to execute in the main world instead of an isolated world, fixing compatibility with scripts injected via context.addInitScript().

Previously, init scripts were installed in the main world but evaluations ran in an isolated v3-world, preventing access to injected functions
Now uses ExecutionContextRegistry to resolve the main world execution context for each frame
Updated documentation comments to reflect the change
Added comprehensive test coverage verifying that functions installed via addInitScript() are callable from page.evaluate()

Confidence Score: 5/5

This PR is safe to merge with minimal risk
The changes are well-tested, properly documented, and address a clear bug where init scripts couldn't be accessed from evaluations due to execution context isolation. The implementation uses an existing, well-designed execution context registry to resolve main world contexts. The test coverage is comprehensive and validates the fix.
No files require special attention

Important Files Changed

File Analysis

Filename	Score	Overview
packages/core/lib/v3/understudy/frame.ts	5/5	Replaced isolated world execution with main world execution for `frame.evaluate()`, using execution context registry
packages/core/lib/v3/understudy/page.ts	5/5	Replaced isolated world execution with main world execution for `page.evaluate()`, `page.title()`, and lifecycle checks

Sequence Diagram

sequenceDiagram
    participant User
    participant Context
    participant Page
    participant CDPSession
    participant ExecutionContextRegistry
    participant Browser

    User->>Context: addInitScript(script)
    Context->>Page: registerInitScript(source)
    Page->>CDPSession: Page.addScriptToEvaluateOnNewDocument
    CDPSession->>Browser: Install script in main world

    User->>Page: goto(url)
    Browser->>CDPSession: Runtime.executionContextCreated
    CDPSession->>ExecutionContextRegistry: Register main world context
    Note over ExecutionContextRegistry: Tracks frameId -> contextId mapping<br/>for main world (isDefault=true)

    User->>Page: evaluate(function)
    Page->>ExecutionContextRegistry: waitForMainWorld(frameId)
    ExecutionContextRegistry-->>Page: Return main world contextId
    Page->>CDPSession: Runtime.evaluate(contextId)
    Note over CDPSession,Browser: Executes in main world<br/>where init scripts are available
    Browser-->>Page: Return result

greptile-apps

_{3 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}

cubic-dev-ai

1 issue found across 4 files

Prompt for AI agents (all 1 issues)


Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="packages/core/lib/v3/tests/context-addInitScript.spec.ts">

<violation number="1" location="packages/core/lib/v3/tests/context-addInitScript.spec.ts:127">
P2: This test uses an external URL (`https://example.com`) while all other tests in this file use the `toDataUrl()` helper to create data URLs. Using an external URL makes the test dependent on network connectivity and potentially flaky. Consider using a data URL for consistency and reliability.</violation>
</file>

_{Reply to cubic to teach it or ask questions. Re-run a review with @cubic-dev-ai review this PR}

packages/core/lib/v3/tests/context-addInitScript.spec.ts

cubic-dev-ai

1 issue found across 4 files

Prompt for AI agents (all 1 issues)


Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="packages/core/lib/v3/tests/context-addInitScript.spec.ts">

<violation number="1" location="packages/core/lib/v3/tests/context-addInitScript.spec.ts:127">
P2: This test uses an external URL (`https://example.com`) while all other tests in this file use `toDataUrl()` for network-independent data URLs. This introduces unnecessary network dependency and potential test flakiness.</violation>
</file>

_{Reply to cubic to teach it or ask questions. Re-run a review with @cubic-dev-ai review this PR}

packages/core/lib/v3/tests/context-addInitScript.spec.ts

@miguelg719

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @browserbasehq/[email protected] ### Patch Changes - [#1388](#1388) [`605ed6b`](605ed6b) Thanks [@miguelg719](https://github.com/miguelg719)! - Fix multiple click event dispatches on CDP and Anthropic CUA handling (double clicks) - [#1400](#1400) [`34e7e5b`](34e7e5b) Thanks [@seanmcguire12](https://github.com/seanmcguire12)! - don't write base64 encoded screenshots to disk when caching agent actions - [#1345](#1345) [`943d2d7`](943d2d7) Thanks [@tkattkat](https://github.com/tkattkat)! - Add support for aborting / stopping an agent run & continuing an agent run using messages from prior runs - [#1334](#1334) [`0e95cd2`](0e95cd2) Thanks [@tkattkat](https://github.com/tkattkat)! - Add support for google vertex provider - [#1410](#1410) [`d4237e4`](d4237e4) Thanks [@seanmcguire12](https://github.com/seanmcguire12)! - fix: include extract in stagehand.history() - [#1315](#1315) [`86975e7`](86975e7) Thanks [@tkattkat](https://github.com/tkattkat)! - Add streaming support to agent through stream:true in the agent config - [#1304](#1304) [`d5e119b`](d5e119b) Thanks [@miguelg719](https://github.com/miguelg719)! - Add support for Microsoft's Fara-7B - [#1346](#1346) [`4e051b2`](4e051b2) Thanks [@seanmcguire12](https://github.com/seanmcguire12)! - fix: don't attach to targets twice - [#1327](#1327) [`6b5a3c9`](6b5a3c9) Thanks [@miguelg719](https://github.com/miguelg719)! - Informed error parsing from api - [#1335](#1335) [`bb85ad9`](bb85ad9) Thanks [@seanmcguire12](https://github.com/seanmcguire12)! - add support for page.addInitScript() - [#1331](#1331) [`88d28cc`](88d28cc) Thanks [@seanmcguire12](https://github.com/seanmcguire12)! - fix: page.evaluate() now works with scripts injected via context.addInitScript() - [#1316](#1316) [`45bcef0`](45bcef0) Thanks [@tkattkat](https://github.com/tkattkat)! - Add support for callbacks in stagehand agent - [#1374](#1374) [`6aa9d45`](6aa9d45) Thanks [@miguelg719](https://github.com/miguelg719)! - Fix key action mapping in Anthropic CUA - [#1330](#1330) [`d382084`](d382084) Thanks [@seanmcguire12](https://github.com/seanmcguire12)! - fix: make act, extract, and observe respect user defined timeout param - [#1336](#1336) [`1df08cc`](1df08cc) Thanks [@tkattkat](https://github.com/tkattkat)! - Patch agent on api - [#1358](#1358) [`2b56600`](2b56600) Thanks [@tkattkat](https://github.com/tkattkat)! - Add support for 4.5 opus in cua agent ## @browserbasehq/[email protected] ### Patch Changes - [#1364](#1364) [`ca0630e`](ca0630e) Thanks [@tkattkat](https://github.com/tkattkat)! - Update model handling in agent evals cli - Updated dependencies \[[`605ed6b`](605ed6b), [`34e7e5b`](34e7e5b), [`943d2d7`](943d2d7), [`0e95cd2`](0e95cd2), [`d4237e4`](d4237e4), [`86975e7`](86975e7), [`d5e119b`](d5e119b), [`4e051b2`](4e051b2), [`6b5a3c9`](6b5a3c9), [`bb85ad9`](bb85ad9), [`88d28cc`](88d28cc), [`45bcef0`](45bcef0), [`6aa9d45`](6aa9d45), [`d382084`](d382084), [`1df08cc`](1df08cc), [`2b56600`](2b56600)]: - @browserbasehq/[email protected] ## @browserbasehq/[email protected] ### Patch Changes - Updated dependencies \[[`605ed6b`](605ed6b), [`34e7e5b`](34e7e5b), [`943d2d7`](943d2d7), [`0e95cd2`](0e95cd2), [`d4237e4`](d4237e4), [`86975e7`](86975e7), [`d5e119b`](d5e119b), [`4e051b2`](4e051b2), [`6b5a3c9`](6b5a3c9), [`bb85ad9`](bb85ad9), [`88d28cc`](88d28cc), [`45bcef0`](45bcef0), [`6aa9d45`](6aa9d45), [`d382084`](d382084), [`1df08cc`](1df08cc), [`2b56600`](2b56600)]: - @browserbasehq/[email protected] Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

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packages/core/lib/v3/tests/context-addInitScript.spec.ts Show resolved Hide resolved

seanmcguire12 added 2 commits December 1, 2025 16:53

make context.addInitScript() use correct isolated world

c341d59

use main world instead of v3 world for addInitScripts & page.evaluate

d4bf59d

seanmcguire12 force-pushed the seanmcguire/stg-1012-make-contextaddinitscript-add-to-correct-js-world branch from 28dcdce to d4bf59d Compare December 2, 2025 00:55

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miguelg719 approved these changes Dec 2, 2025

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seanmcguire12 merged commit 88d28cc into main Dec 2, 2025
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[fix]: make `page.evaluate()` use main world #1331

[fix]: make `page.evaluate()` use main world #1331

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seanmcguire12 commented Dec 2, 2025 •

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[fix]: make page.evaluate() use main world #1331

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seanmcguire12 commented Dec 2, 2025 • edited by cubic-dev-ai bot Loading Uh oh! There was an error while loading. Please reload this page.

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why

what changed

test plan

Summary by cubic

Why:

What:

Test Plan:

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greptile-apps bot commented Dec 2, 2025

Greptile Overview

Greptile Summary

Confidence Score: 5/5

Important Files Changed

Sequence Diagram

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[fix]: make `page.evaluate()` use main world #1331

[fix]: make `page.evaluate()` use main world #1331

seanmcguire12 commented Dec 2, 2025 •

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