**2 issues found** across 14 files Confidence score: **3/5** - There is a concrete regression risk in `packages/core/lib/v3/handlers/handlerUtils/actHandlerUtils.ts`: writing `_valueTracker` to the same value as the DOM can bypass React’s change detection and cause `onChange` not to fire on subsequent events. - The update in `packages/core/lib/v3/understudy/frameRegistry.ts` appears mostly low risk functionally, but the JSDoc no longer matches behavior for non-root `swap` detaches, which can mislead future maintenance. - Given one user-facing behavior risk (moderate severity, good confidence) plus one documentation inconsistency, this looks mergeable with caution rather than fully low-risk. - Pay close attention to `packages/core/lib/v3/handlers/handlerUtils/actHandlerUtils.ts` and `packages/core/lib/v3/understudy/frameRegistry.ts` - verify `onChange` event behavior and align docs with the narrowed swap-detach semantics.

Prompt for AI agents (unresolved issues)

```text Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately. P2: The method's JSDoc still says "For `swap` we keep the node to preserve continuity", but this change narrows that behavior to root frames only. Update the JSDoc to reflect that non-root swap detaches now remove the subtree, so future maintainers don't rely on the stale contract. (Based on your team's feedback about documenting complex logic and edge-case interactions inline.) [FEEDBACK_USED] P2: Setting `_valueTracker` to the same value just written to the DOM defeats React's change detection. React compares `tracker.getValue()` to the current DOM value on the next event — if they match, `onChange` never fires. Set the tracker to a different value (e.g., empty string) so React sees the change. ```

Architecture diagram

```mermaid sequenceDiagram participant Agent as Agent / LLM participant Tools as AgentTools (Queue) participant Act as ActHandler participant FL as FrameLocator participant Registry as FrameRegistry participant Page as Page (CDP Sessions) participant Browser as Browser (Shopify/PCI) Note over Agent,Browser: [STG-1824] Stabilized Iframe & Action Flow Agent->>Tools: execute(toolCall) activate Tools Note right of Tools: NEW: Serialized execution queue
prevents overlapping browser actions Tools->>Tools: wait for executionChain Tools->>Act: performUnderstudyMethod() activate Act Act->>FL: resolveLocatorTarget(selector) activate FL FL->>Page: describeNode(selector) Page-->>FL: node (frameId, backendNodeId) opt CHANGED: If frameId present or OOPIF FL->>Page: resolvedOwnerSession(frameId) Note right of Page: NEW: Probes all sessions via getFrameTree
to find real owner for stale IDs Page-->>FL: activeSession FL->>Registry: seedFromFrameTree(sessionId, tree) Note right of Registry: CHANGED: Force overwrite stale
ownership from parent session end FL-->>Act: target (frame, selector) deactivate FL alt NEW: Target is Shopify PCI Iframe Act->>Act: hintedIframeTextSelector(title) Note right of Act: Maps iframe title (e.g. "Card number")
to inner PCI input Act->>Browser: setFrameTextEntryValue(innerSelector, value) Act->>Browser: waitForTimeout(settleMs) Note right of Browser: Wait for Shopify checkout state to stabilize else Standard Interaction Act->>Browser: click / type / fill end alt CHANGED: Transient Frame Error Browser-->>Act: Error (e.g. "Main world not ready") Act->>Act: Retry (up to 4 attempts) else Success Browser-->>Act: OK end Act-->>Tools: result deactivate Act Tools-->>Agent: tool result deactivate Tools ```

_{Reply with feedback, questions, or to request a fix. Tag `@cubic-dev-ai` to re-run a review, or [fix all with cubic](https://www.cubic.dev/action/fix/pr/browserbase/stagehand/2003/ai_pr_review_1776295096517_fd4bcd41-d172-4c45-8d7b-b02f88a3a5e3?entrySource=github_ui_to_cubic_ui).}