Mobile: long responses with many tool calls truncate final summary text

[dimakis]

Description

When Claude Code returns a long response containing many sequential tool calls (10+) followed by a concluding text message, the mobile web UI truncates the output — the final summary text after the tool calls is not visible and cannot be scrolled to.

Steps to reproduce

1. Open Mitzo on a mobile browser (observed on phone at 100.91.50.57:3100)
2. Send a prompt that triggers a response with ~15 tool calls (e.g., a task involving multiple Write, Bash, and TodoWrite calls in sequence)
3. Wait for the response to complete
4. Try to scroll down to see the full response

Expected behavior

The full response should be visible, including any summary/concluding text that appears after the tool call blocks. The user should be able to scroll to the bottom of the message.

Actual behavior

The tool call blocks render, but the concluding text message after the tool calls is cut off. The user cannot scroll past the tool calls to see the final summary.

Context

• Observed: 2026-04-04 at 14:21
• Client: Mobile browser at 100.91.50.57:3100
• Response shape: ~15 tool calls (Write, Bash, TodoWrite) followed by a text summary block
• The tool calls themselves rendered — the issue is specifically that the text block after them was not visible

Possible areas to investigate

• ChatView / MessageBubble rendering — does the container height accommodate all blocks?
• groupMessages / groupBlocks — could grouping logic be dropping trailing text blocks?
• useChatMessages reducer — is MESSAGE_END or SESSION_END finalizing the message before the last text block arrives?
• Mobile viewport / scroll container CSS — overflow or max-height cutting off content
• ToolGroup component — if tool blocks are grouped, does the group container allow content after it?

Labels

bug, mobile, frontend

[dimakis]

Additional reproduction: screen lock/unlock loses content

Same issue manifests when the phone screen locks and unlocks during a long response:

• Response has assistant text → multiple tool calls → assistant summary text
• After screen lock/unlock, the final assistant text after tool calls is not visible
• The chat appears to end at the last tool call with no summary

Screenshot shows the response cutting off after Read/Bash/Read tool calls — the analysis text that followed is gone.

This might be two related bugs:

1. Truncation on initial render (original report) — long tool call sequences cut off the trailing text
2. Scroll/render loss on visibility change — visibilitychange or page restoration drops content

Worth checking if useChatMessages or the message grouping logic drops trailing text content blocks when re-rendering after a visibility change.

[dimakis]

Additional: background agent completion notification not rendered

When a background agent completes, the system notification arrives (visible in the conversation) but the agent's result text is not rendered in the chat UI. The user sees the notification badge/toast but the actual content is missing from the message thread.

This is a third manifestation of the same rendering issue — content blocks that arrive asynchronously (tool results, agent completions) may not be appended to the visible DOM.