What is the issue?

Several small performance issues across the message rendering pipeline add up, especially in chats with many tool calls:

1. Tool call arguments are re-parsed on every render — BrowserToolCallDisplay calls JSON.parse on tool call arguments during render without memoizing the result. Every re-render (e.g., during streaming) re-parses the same JSON.

2. Collapsed tool results still run JSON.stringify — When a tool result is collapsed and invisible, the component still stringifies the raw JSON on every render. This should be deferred until the user actually expands the section.

3. Message memo comparator is missing lastToolQuery — The custom React.memo comparator for the Message component doesn't include lastToolQuery in the comparison, which can cause missed memoization opportunities or stale renders.

4. lastToolQueries recalculates on every streaming token — The memoized computation depends on the full messages array reference, which changes on every streamed token. Using messages.length as the dependency would prevent unnecessary recalculations since tool queries only change when new messages are added.

5. Unreachable code after early returns — In ToolCallDisplay, there's a code path that checks for browser.* tool names that can never be reached because a previous branch already handles all non-browser.* names and returns.

6. browserToolResult prop is untyped — The prop is typed as any in MessageList instead of using the existing BrowserToolResult type.

Relevant log output

OS

macOS

GPU

Apple

CPU

Apple

Ollama version

No response