fix(web,mobile): image-only messages show the image, not the placeholder prompt#26769

External image Run configuration

• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: t3/improve-image-message-preview
• File: .coderabbit.config.ts
• Commit: e40bd88
• Layers: Repository TS config
• Review profile: CHILL
• Plan: Advanced
• Run ID: 9407cec9-9add-4e71-a151-9afe5f30defd

External image Commits

Reviewing files that changed from the base of the PR and between 508dadbac4899309556793e6156615f68623432a and e40bd88cf8e5c64645c60f614044cd87d4d6e7cd.

External image Files selected for processing: 2

• apps/mobile/src/features/threads/ThreadFeed.tsx
• apps/web/src/components/chat/TimelineUserMessageRow.tsx

External image Files skipped from review as they are similar to previous changes: 1

• apps/mobile/src/features/threads/ThreadFeed.tsx

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The shared prompt detector suppresses attachment-only bootstrap text from message presentation, search results, and queue previews. Web and mobile thread views adjust bubble and media layouts for eligible media-only messages.

Changes: Attachment-only message presentation

Layer / File(s)	Summary
Detect and suppress the bootstrap prompt packages/shared/src/composerContextReferences.ts, packages/client-runtime/src/userMessage.ts, packages/client-runtime/src/userMessage.test.ts, packages/shared/src/threadFindText.ts, packages/shared/src/threadFindText.test.ts, apps/mobile/src/features/threads/threadQueueControlPresentation.ts, apps/web/src/components/chat/QueuedRunsControl.tsx	A shared helper recognizes the attachment-only bootstrap prompt, including an optional leading Ultrathink: prefix. Message presentation, search results, and queue previews omit matching prompt text. Tests cover message presentation and search behavior.
Render media-only messages on web apps/web/src/components/chat/TimelineUserMessageRow.tsx	Context resolution uses presented text. Eligible media-only messages omit bubble background and padding. Image layouts distinguish lone images and collages from ordinary attachments.
Render media-only messages on mobile apps/mobile/src/features/threads/ThreadFeed.tsx	Eligible image-only messages omit bubble background and padding. Visible non-inline images can fill the bubble width. Message body rendering checks presented text.

Priority: External image Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Possibly related PRs

• pingdotgg/t3code#25873 — Adds visible-text handling to hide the attachment-only prompt in web, mobile, and queue views.
• pingdotgg/t3code#24104 — Adds guest attribution and guest-specific message presentation, which affects the media-only rendering condition.
• pingdotgg/t3code#23613 — Changes web and mobile presentation of attachment-only bootstrap prompts.

Suggested reviewers: shivamhwp, juliusmarminge, t3dotgg

Rare messages matching the bootstrap sentence can disappear or be omitted from search. This is a limited merge risk.

^Failed Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Description check	Warning	The description clearly explains the problem, implementation, UI behavior, verification results, limitations, screenshots, and agent details. However, it does not follow the required section structure…	Organize the description under the required Problem, Change, Scope and approval, and Verification headings. Add a link to the triaged issue or discussion with explicit maintainer approval and the approval comment, or explain why this focuse…

^Passed Passed checks: 3 passed

Check name	Status	Explanation
Title check	Passed	The title clearly and concisely describes the main change: image-only messages display the image instead of the placeholder prompt.
Linked Issues check	Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	Passed	Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description clearly explains the problem, implementation, UI behavior, verification results, limitations, screenshots, and agent details. However, it does not follow the required section structure and does not provide the required triaged issue or explicit maintainer approval for scope and direction.

Resolution

Organize the description under the required Problem, Change, Scope and approval, and Verification headings. Add a link to the triaged issue or discussion with explicit maintainer approval and the approval comment, or explain why this focused fix qualifies for the exemption. Keep the verification results, screenshots, unverified items, and agent details in the appropriate sections.

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10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB