session-cost/spent-value under reported for sessions with 100+ messages

[IdrisGit]

Description

The TUI sidebar displays incorrect spent value for sessions that exceed 100 messages. The cost only accumulates from the last 100 messages stored in memory, not from all messages that exist in the session.

Plugins

No response

OpenCode version

1.1.12

Steps to reproduce

1. Start a new session with a paid model.
2. Continue conversation until you have > 100 messages (requires iterative work over several hours/days).
3. Check the spent value displayed in the sidebar.
4. Compare with actual cost (using Zen dashboard).

Expected: Sidebar shows accurate total cost from all messages including messages that were reverted.
Actual: Sidebar shows cost only from the last ~100 messages.

Screenshot and/or share link

No response

Operating System

Arch Linux (Omarchy)

Terminal

Ghostty

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• [TUI] $ spent in context decreases after request #6989: [TUI] $ spent in context decreases after request - Similar issue with spent value calculations being incorrect
• Multi Model Cost Calculations are Bugged #7387: Multi Model Cost Calculations are Bugged - Cost calculation issues when using multiple models in a session
• The token cost generated by session titles, message summary titles, and body summaries has not been accounted for. #7175: The token cost generated by session titles, message summary titles, and body summaries has not been accounted for - Related cost accounting issue
• Cost in storage/session is always 0 #2891: Cost in storage/session is always 0 - Related cost tracking issue

Feel free to ignore if none of these address your specific case.