✏️ refactor: Read the Inline Editors' Messages View Through the Parts Host

[berry-13]

Summary

EditContentParts and UIResourceCarousel were two more Messages/Content siblings reading the app directly: the editor took the chat direction from Recoil and the conversation and operations from the messages view providers, and the carousel took ask from the optional operations context.

This adds useChatDirection to MessagePartsHost, and two app-owned members to the augmentation in hooks/Chat/contract.ts, the same way useArtifactPanel is declared: useMessagesEditing (conversation, ask, getMessages, setMessages) and useMessagesAsk, which keeps the no-op outside a messages view. Their type is a Pick of the messages view's own value, so nothing is duplicated. The app host backs each with the provider or atom the component read before.

Stacked on #17171. EditMessage follows in the next link because it overlaps open contributor PRs.

Type of change

• Refactor

Testing

Tested environments/configuration:

Local jest and typecheck; no runtime configuration matters for this change.

Automated tests:

• cd client && npx jest src/components/Chat/Messages src/components/MCPUIResource src/Providers src/components/Share src/components/Chat/Subagents: 141 suites, 2,577 tests pass, including the existing EditContentParts, UIResourceCarousel and MCPUIResourceCarousel specs, which now reach the app through the host.
• cd packages/chat && npx jest: 36 suites, 388 tests pass; every host fixture carries the new members.
• npx tsc --noEmit for client and packages/chat, and the package build, are clean. ESLint, Prettier and import sorting are clean on every changed file.
• The audit's parts-context.sh over Messages/Content reports 5 of 115 files (7 on 🧱 refactor: Read Message Content Siblings Through the Parts Host #17171).

Screenshots / recordings

No user-facing change.

Risk / compatibility

Low. Each member returns what the component read before; useChatDirection normalizes the stored LTR/RTL to the lowercase value the editor already compared against.

Checklist

• I reviewed my own changes
• Relevant tests have been added or updated
• Existing relevant tests pass
• The change does not introduce new warnings or errors

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-16T20:07:12.513161Z	2e57e58	New commits
🔒 Security Review	✅ Completed 2026-10-15T18:01:47.145329Z	759e31f	Draft marked ready

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