Describe the bug

The Goose UI fails to display tool outputs and MCP UI components for sequentially executed tools. When multiple tools are called in sequence (one after another), only the first tool's output is rendered in the UI with both "Tool Details" and "Output" sections visible. All subsequent tools only show "Tool Details" without any visible output section, including MCP UI components.

However, when the same tools are called in parallel (at once), the UI correctly renders all tool outputs and MCP UI components simultaneously.

logs
tool-calls-in-sequence__20250930_135612.txt
tool-calls-at-once__20250930_135657.txt

To Reproduce

Steps to reproduce the behavior:

Scenario 1: Sequential tool calls (reproduces the bug)

1. In Goose UI, ask the assistant to execute tools sequentially with a prompt like: "I want you to call a few in sequence: write a new file to my desktop and write a poem about flowers, read that file, then Tool Call: _mcpaharvard__demo-mcp-ui-actions"
2. Observe that only the first tool (writing file) displays both "Tool Details" and "Output" sections
3. Notice that subsequent tools (reading file, MCP demo) only show "Tool Details" without any visible output
4. The MCP UI is not rendered for the third tool call

Scenario 2: Parallel tool calls (works correctly)

1. In Goose UI, ask the assistant to execute the same tools at once with a prompt like: "I want you to call a few tools at once: write a new file to my desktop and write a poem about flowers, read that file, then Tool Call: _mcpaharvard__demo-mcp-ui-actions"
2. Observe that all three tools display both "Tool Details" and "Output" sections simultaneously
3. The MCP UI is properly rendered and visible

Expected behavior

All tool outputs should be displayed in the UI regardless of whether tools are executed sequentially or in parallel. Each tool call should show:

• Tool Details section
• Output section with the tool's response
• MCP UI components (when applicable)

Screenshots

See attached comparison image showing:

• Left side: Sequential execution where only the first tool shows output
• Right side: Parallel execution where all tools show output and MCP UI is visible

Reference files:

• tool-calls-in-sequence__20250930_135612.jsonl - Sequential execution session
• tool-calls-at-once__20250930_135657.jsonl - Parallel execution session

Please provide following information:

• OS & Arch: macOS (darwin 24.6.0)
• Interface: UI
• Version: 1.9.0-block
• Extensions enabled: Developer, MCP Aharvard
• Provider & Model: gpt-5 and claude-4-sonnet

Additional context

This appears to be a UI rendering issue specific to how Goose handles sequential tool execution. The underlying tool execution appears to work correctly (both scenarios complete successfully and produce the same results), but the UI display behavior differs:

• Sequential execution: 8 messages total, only first tool output visible in UI
• Parallel execution: 4 messages total, all tool outputs visible in UI