Claude Code on the web: option to collapse Write/Edit diff cards by default (including the active one)

Surface

Claude Code on the web (claude.ai/code) — the cloud harness, not the terminal CLI or IDE extensions.

Problem

When Claude uses the Write or Edit tool, the tool-call card in the chat transcript renders the full red/green diff inline and fully expanded. On any non-trivial change this floods the conversation view and pushes everything else off screen.

There is currently no setting, toggle, account/workspace preference, URL parameter, or per-message control in the web UI to render these diff cards collapsed. The chat transcript also has no click-to-collapse on the inline card itself — clicking the +N -M indicator only opens a separate diff panel, which doesn't shrink the inline card.

Requested behavior

An option to render Write/Edit tool-call cards collapsed to a one-line summary by default (e.g. Updated foo.py (+42 -18)), expandable on demand by clicking — and critically, this should apply to the most recent / active card too, not just older ones. Today even a "collapse older cards" heuristic wouldn't help, because it's the recent large diff that overloads the screen.

Ideally configurable as one of:

• a global "compact tool calls" / "collapse diffs by default" toggle in the web UI, or
• an account/workspace preference, or
• at minimum, click-to-collapse on the inline diff card.

Related issues (same ask, other surfaces)

• #37584 — Option to collapse file edit diffs by default (expand on demand)
• #49646 — Configurable tool call visibility (hide / collapse / group) — VS Code extension
• #36462 — Collapsible tool outputs — terminal UI
• #17734 — Disable/collapse diff output in terminal

This issue is specifically scoped to the web app, where none of the above workarounds (e.g. the terminal's fullscreen renderer) are available, so the diff is always fully expanded with no way to compact it.