fix(web): suppress Task tool prompt text from leaking into chat (#372)

web/src/chat/normalizeAgent.ts

@@ -109,6 +109,18 @@ function normalizeUserOutput(
 
     const messageContent = message.content
 
+    // Skip system-injected messages that were logged as type:'user' but are
+    // not text the human actually typed (task notifications, command caveats, etc.)
+    if (typeof messageContent === 'string') {
+        const trimmed = messageContent.trimStart()
+        if (
+            trimmed.startsWith('<task-notification>') ||
+            trimmed.startsWith('<system-reminder>')
+        ) {
+            return null
+        }
+    }
+
     if (isSidechain && typeof messageContent === 'string') {
         return {
             id: messageId,

web/src/chat/reducerTimeline.ts

@@ -73,9 +73,28 @@ export function reduceTimeline(
         }
 
         if (msg.role === 'agent') {
+            // When the message contains a Task tool_use, Claude often writes the
+            // prompt as a text block before the tool_use block.  We only want to
+            // suppress that exact prompt text — not every text block in the message.
+            const taskToolCall = msg.content.find(
+                (c) => c.type === 'tool-call' && c.name === 'Task'
+            )
+            const taskPromptText: string | null = (() => {
+                if (!taskToolCall || taskToolCall.type !== 'tool-call') return null
+                const input = taskToolCall.input
+                if (typeof input === 'object' && input !== null && 'prompt' in input) {
+                    const p = (input as { prompt: unknown }).prompt
+                    if (typeof p === 'string') return p
+                }
+                return null
+            })()
+
             for (let idx = 0; idx < msg.content.length; idx += 1) {
                 const c = msg.content[idx]
                 if (c.type === 'text') {
+                    // Skip text blocks that are just the Task tool prompt (already shown in tool card)
+                    if (taskPromptText && c.text.trim() === taskPromptText.trim()) continue
+
                     if (isCliOutputText(c.text, msg.meta)) {
                         blocks.push(createCliOutputBlock({
                             id: `${msg.id}:${idx}`,