coalesce cursor thinking deltas in run log streaming

packages/adapter-utils/src/types.ts

@@ -136,7 +136,7 @@ export interface ServerAdapterModule {
 
 export type TranscriptEntry =
   | { kind: "assistant"; ts: string; text: string }
-  | { kind: "thinking"; ts: string; text: string }
+  | { kind: "thinking"; ts: string; text: string; delta?: boolean }
   | { kind: "user"; ts: string; text: string }
   | { kind: "tool_call"; ts: string; name: string; input: unknown }
   | { kind: "tool_result"; ts: string; toolUseId: string; content: string; isError: boolean }

packages/adapters/cursor-local/src/ui/parse-stdout.ts

@@ -219,8 +219,10 @@ export function parseCursorStdoutLine(line: string, ts: string): TranscriptEntry
 
   if (type === "thinking") {
     const text = asString(parsed.text).trim() || asString(asRecord(parsed.delta)?.text).trim();
+    const subtype = asString(parsed.subtype).trim().toLowerCase();
+    const isDelta = subtype === "delta" || asRecord(parsed.delta) !== null;
     if (!text) return [];
-    return [{ kind: "thinking", ts, text }];
+    return [{ kind: "thinking", ts, text, ...(isDelta ? { delta: true } : {}) }];
   }
 
   if (type === "tool_call") {

server/src/__tests__/cursor-local-adapter.test.ts

@@ -162,7 +162,7 @@ describe("cursor ui stdout parser", () => {
         }),
         ts,
       ),
-    ).toEqual([{ kind: "thinking", ts, text: "planning next command" }]);
+    ).toEqual([{ kind: "thinking", ts, text: "planning next command", delta: true }]);
 
     expect(
       parseCursorStdoutLine(

ui/src/adapters/transcript.ts

@@ -2,6 +2,18 @@ import type { TranscriptEntry, StdoutLineParser } from "./types";
 
 type RunLogChunk = { ts: string; stream: "stdout" | "stderr" | "system"; chunk: string };
 
+function appendTranscriptEntry(entries: TranscriptEntry[], entry: TranscriptEntry) {
+  if (entry.kind === "thinking" && entry.delta) {
+    const last = entries[entries.length - 1];
+    if (last && last.kind === "thinking" && last.delta) {
+      last.text += entry.text;
+      last.ts = entry.ts;
+      return;
+    }
+  }
+  entries.push(entry);
+}
+
 export function buildTranscript(chunks: RunLogChunk[], parser: StdoutLineParser): TranscriptEntry[] {
   const entries: TranscriptEntry[] = [];
   let stdoutBuffer = "";
@@ -22,14 +34,18 @@ export function buildTranscript(chunks: RunLogChunk[], parser: StdoutLineParser)
     for (const line of lines) {
       const trimmed = line.trim();
       if (!trimmed) continue;
-      entries.push(...parser(trimmed, chunk.ts));
+      for (const entry of parser(trimmed, chunk.ts)) {
+        appendTranscriptEntry(entries, entry);
+      }
     }
   }
 
   const trailing = stdoutBuffer.trim();
   if (trailing) {
     const ts = chunks.length > 0 ? chunks[chunks.length - 1]!.ts : new Date().toISOString();
-    entries.push(...parser(trailing, ts));
+    for (const entry of parser(trailing, ts)) {
+      appendTranscriptEntry(entries, entry);
+    }
   }
 
   return entries;

ui/src/components/ActiveAgentsPanel.tsx

@@ -97,6 +97,25 @@ function parseStdoutChunk(
   pendingByRun.set(pendingKey, split.pop() ?? "");
   const adapter = getUIAdapter(run.adapterType);
 
+  const summarized: Array<{ text: string; tone: FeedTone; thinkingDelta?: boolean }> = [];
+  const appendSummary = (entry: TranscriptEntry) => {
+    if (entry.kind === "thinking" && entry.delta) {
+      const text = entry.text.trim();
+      if (!text) return;
+      const last = summarized[summarized.length - 1];
+      if (last && last.thinkingDelta) {
+        last.text += text;
+      } else {
+        summarized.push({ text: `[thinking] ${text}`, tone: "info", thinkingDelta: true });
+      }
+      return;
+    }
+
+    const summary = summarizeEntry(entry);
+    if (!summary) return;
+    summarized.push({ text: summary.text, tone: summary.tone });
+  };
+
   const items: FeedItem[] = [];
   for (const line of split.slice(-8)) {
     const trimmed = line.trim();
@@ -108,13 +127,15 @@ function parseStdoutChunk(
       continue;
     }
     for (const entry of parsed) {
-      const summary = summarizeEntry(entry);
+      appendSummary(entry);
-      if (!summary) continue;
-      const item = createFeedItem(run, ts, summary.text, summary.tone, nextIdRef.current++);
-      if (item) items.push(item);
     }
   }
 
+  for (const summary of summarized) {
+    const item = createFeedItem(run, ts, summary.text, summary.tone, nextIdRef.current++);
+    if (item) items.push(item);
+  }
+
   return items;
 }
 

ui/src/components/LiveRunWidget.tsx

@@ -108,6 +108,25 @@ function parseStdoutChunk(
   pendingByRun.set(pendingKey, split.pop() ?? "");
   const adapter = getUIAdapter(run.adapterType);
 
+  const summarized: Array<{ text: string; tone: FeedTone; thinkingDelta?: boolean }> = [];
+  const appendSummary = (entry: TranscriptEntry) => {
+    if (entry.kind === "thinking" && entry.delta) {
+      const text = entry.text.trim();
+      if (!text) return;
+      const last = summarized[summarized.length - 1];
+      if (last && last.thinkingDelta) {
+        last.text += text;
+      } else {
+        summarized.push({ text: `[thinking] ${text}`, tone: "info", thinkingDelta: true });
+      }
+      return;
+    }
+
+    const summary = summarizeEntry(entry);
+    if (!summary) return;
+    summarized.push({ text: summary.text, tone: summary.tone });
+  };
+
   const items: FeedItem[] = [];
   for (const line of split.slice(-8)) {
     const trimmed = line.trim();
@@ -119,13 +138,15 @@ function parseStdoutChunk(
       continue;
     }
     for (const entry of parsed) {
-      const summary = summarizeEntry(entry);
+      appendSummary(entry);
-      if (!summary) continue;
-      const item = createFeedItem(run, ts, summary.text, summary.tone, nextIdRef.current++);
-      if (item) items.push(item);
     }
   }
 
+  for (const summary of summarized) {
+    const item = createFeedItem(run, ts, summary.text, summary.tone, nextIdRef.current++);
+    if (item) items.push(item);
+  }
+
   return items;
 }