From 32f2ee3da5cd28dc693ec736eba7d9035005bf35 Mon Sep 17 00:00:00 2001
From: Daniel Sauer <daniel.a.d.sauer@gmail.com>
Date: Sat, 17 Jan 2026 23:45:41 +0100
Subject: [PATCH 1/2] feat(ui): Add thinking/reasoning block visibility toggle

Add toggle button to show/hide thinking blocks after response completion.
Currently, reasoning blocks are only visible during streaming and disappear
once the response is complete.

Changes:
- Add showReasoning state to session turn store
- Add hasReasoningParts() memo to detect if turn has reasoning content
- Show toggle button in response header when reasoning parts exist
- Add reasoning section at bottom of response when toggled on
- Keep reasoning visible during streaming (existing behavior)

Fixes #7866
---
 packages/ui/src/components/session-turn.tsx | 32 ++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/packages/ui/src/components/session-turn.tsx b/packages/ui/src/components/session-turn.tsx
index c03622105916..ea034afcf8c9 100644
--- a/packages/ui/src/components/session-turn.tsx
+++ b/packages/ui/src/components/session-turn.tsx
@@ -378,6 +378,17 @@ export function SessionTurn(
 
   const isShellMode = createMemo(() => !!shellModePart())
 
+  const hasReasoningParts = createMemo(() => {
+    for (const m of assistantMessages()) {
+      const msgParts = data.store.part[m.id]
+      if (!msgParts) continue
+      for (const p of msgParts) {
+        if (p?.type === "reasoning") return true
+      }
+    }
+    return false
+  })
+
   const rawStatus = createMemo(() => {
     const msgs = assistantMessages()
     let last: PartType | undefined
@@ -514,6 +525,8 @@ export function SessionTurn(
     retrySeconds: 0,
     status: rawStatus(),
     duration: duration(),
+    userMessageHovered: false,
+    showReasoning: false,
   })
 
   createEffect(() => {
@@ -747,7 +760,7 @@ export function SessionTurn(
                               message={assistantMessage}
                               responsePartId={responsePartId()}
                               hideResponsePart={hideResponsePart()}
-                              hideReasoning={!working()}
+                              hideReasoning={!working() && !store.showReasoning}
                               hidden={hidden}
                             />
                           )}
@@ -775,6 +788,22 @@ export function SessionTurn(
                         <div data-slot="session-turn-summary-header">
                           <div data-slot="session-turn-summary-title-row">
                             <h2 data-slot="session-turn-summary-title">{i18n.t("ui.sessionTurn.summary.response")}</h2>
+
+                            <Show when={hasReasoningParts()}>
+                              <Button
+                                data-slot="session-turn-thinking-toggle"
+                                variant="ghost"
+                                size="small"
+                                onMouseDown={(e) => e.preventDefault()}
+                                onClick={(event) => {
+                                  event.stopPropagation()
+                                  setStore("showReasoning", (prev) => !prev)
+                                }}
+                              >
+                                {store.showReasoning ? "Hide thinking" : "Show thinking"}
+                              </Button>
+                            </Show>
+
                             <Show when={response()}>
                               <div data-slot="session-turn-response-copy-wrapper">
                                 <Tooltip
@@ -797,6 +826,7 @@ export function SessionTurn(
                               </div>
                             </Show>
                           </div>
+
                           <div data-slot="session-turn-response">
                             <Markdown
                               data-slot="session-turn-markdown"

From a5ec579e4e6ea64d54aea9fb18d30175fdda863e Mon Sep 17 00:00:00 2001
From: Daniel Sauer <daniel.a.d.sauer@gmail.com>
Date: Tue, 10 Feb 2026 20:33:46 +0100
Subject: [PATCH 2/2] chore(ui): type mouse events in thinking toggle

---
 packages/ui/src/components/session-turn.tsx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/ui/src/components/session-turn.tsx b/packages/ui/src/components/session-turn.tsx
index ea034afcf8c9..abad3879cfc8 100644
--- a/packages/ui/src/components/session-turn.tsx
+++ b/packages/ui/src/components/session-turn.tsx
@@ -794,8 +794,8 @@ export function SessionTurn(
                                 data-slot="session-turn-thinking-toggle"
                                 variant="ghost"
                                 size="small"
-                                onMouseDown={(e) => e.preventDefault()}
-                                onClick={(event) => {
+                                onMouseDown={(e: MouseEvent) => e.preventDefault()}
+                                onClick={(event: MouseEvent) => {
                                   event.stopPropagation()
                                   setStore("showReasoning", (prev) => !prev)
                                 }}