fix(seer-explorer): Do not open a reasoning box that renders nothing

`hasTrace` opened the box whenever a block had tool calls, but `ToolCallList` suppresses a call that reported no rows, links, todos or markdown. A settled Code Mode call that produced nothing therefore left an empty box between the previous answer and the next spinner.

Both now go through one predicate, so the container and its contents cannot disagree.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: azulus

static/app/views/seerExplorer/components/chat/responseGroup.spec.tsx

@@ -120,6 +120,79 @@ describe('ResponseGroup', () => {
     expect(screen.getByText('The final answer')).toBeInTheDocument();
   });
 
+  it('does not open a reasoning box for a call that renders nothing', () => {
+    // `ToolCallList` suppresses a settled call that reported no rows, links, todos or markdown.
+    // Counting it as a trace anyway left an empty box between the previous answer and the next
+    // spinner.
+    const group: Block[] = [
+      {
+        id: 't1',
+        message: {
+          role: 'tool_use',
+          content: null,
+          tool_calls: [{id: 't1-call', function: 'sentry_api_execute', args: '{}'}],
+        },
+        timestamp: '2024-01-01T00:01:00Z',
+        loading: false,
+        tool_results: [
+          {
+            tool_call_id: 't1-call',
+            tool_call_function: 'sentry_api_execute',
+            content: 'ok',
+            structuredContent: null,
+          },
+        ],
+      },
+    ];
+
+    render(<ResponseGroup group={group} blockIndex={1} blocks={group} showThinking />, {
+      organization,
+    });
+
+    expect(screen.queryByRole('button', {name: /Thinking/})).not.toBeInTheDocument();
+  });
+
+  it('still opens the box when the call reported call records', () => {
+    const group: Block[] = [
+      {
+        id: 't1',
+        message: {
+          role: 'tool_use',
+          content: null,
+          tool_calls: [{id: 't1-call', function: 'sentry_api_execute', args: '{}'}],
+        },
+        timestamp: '2024-01-01T00:01:00Z',
+        loading: false,
+        tool_results: [
+          {
+            tool_call_id: 't1-call',
+            tool_call_function: 'sentry_api_execute',
+            content: 'ok',
+            structuredContent: {
+              calls: [{id: 1, kind: 'api', title: 'Retrieving issue 4521'}],
+            },
+          },
+        ],
+      },
+    ];
+
+    render(<ResponseGroup group={group} blockIndex={1} blocks={group} showThinking />, {
+      organization,
+    });
+
+    expect(screen.getByRole('button', {name: /Thinking|Retrieving/})).toBeInTheDocument();
+  });
+
+  it('still opens the box for a classic tool call', () => {
+    const group = [toolUseBlock('t1')];
+
+    render(<ResponseGroup group={group} blockIndex={1} blocks={group} showThinking />, {
+      organization,
+    });
+
+    expect(screen.getByRole('button', {name: /Queried/})).toBeInTheDocument();
+  });
+
   it('collapses the reasoning until it is expanded', async () => {
     const group = [
       toolUseBlock('t1', {thinking_content: 'my private reasoning'}),

static/app/views/seerExplorer/components/chat/responseGroup.tsx

@@ -18,7 +18,7 @@ import {getToolsStringFromBlock} from 'sentry/views/seerExplorer/utils';
 
 import {AssistantBlock} from './assistant';
 import {MessagePlaceholder, hasValidContent} from './shared';
-import {CODE_MODE_TOOLS, ToolCallList} from './toolUse';
+import {CODE_MODE_TOOLS, ToolCallList, blockRendersToolContent} from './toolUse';
 
 /**
  * One assistant response: a run of consecutive `assistant`/`tool_use` blocks that follows a user
@@ -171,7 +171,9 @@ export function ResponseGroup({
     return (
       (showThinking && hasValidContent(block.message.thinking_content)) ||
       (!isAnswer && hasValidContent(block.message.content)) ||
-      Boolean(block.message.tool_calls?.length)
+      // Not `tool_calls.length`: a call that reported nothing renders no row, and counting it
+      // opens a reasoning box with an empty body.
+      blockRendersToolContent(block, blocks)
     );
   });
 

static/app/views/seerExplorer/components/chat/toolUse.tsx

@@ -94,6 +94,51 @@ function linkKey(link: ToolLink) {
   return `${link.kind}:${sorted}`;
 }
 
+/**
+ * Whether `ToolCallList` will render anything for this block.
+ *
+ * `ToolCallList` suppresses a tool call that reported nothing, so a caller deciding whether to open
+ * a container around it cannot go by `tool_calls.length` — that opens an empty box.
+ *
+ * Deliberately the same terms as the per-call `hasContent` guard below, minus the residual-link
+ * filtering: residual links are only consumed by rows, and rows already make this true.
+ */
+export function blockRendersToolContent(block: Block, blocks?: Block[]): boolean {
+  const toolCalls = block.message.tool_calls ?? [];
+  if (!toolCalls.length) {
+    return false;
+  }
+  const toolsUsed = getToolsStringFromBlock(block);
+  const results = block.tool_results ?? [];
+  const latestTodos = findLatestTodos(blocks);
+
+  if (latestTodos?.block === block) {
+    return true;
+  }
+  if (block.live_calls?.length) {
+    return true;
+  }
+  if ((block.tool_links ?? []).some(link => link && !link.params?.is_error)) {
+    return true;
+  }
+  if (
+    results.some(result => {
+      const structured = result?.structuredContent;
+      return Boolean(
+        structured?.calls?.length ||
+        structured?.links?.length ||
+        structured?.todos?.length ||
+        (structured && result.content.trimStart().startsWith('{%'))
+      );
+    })
+  ) {
+    return true;
+  }
+  return toolCalls.some(
+    (toolCall, idx) => !CODE_MODE_TOOLS.has(toolCall.function) && Boolean(toolsUsed[idx])
+  );
+}
+
 export function ToolUseBlock({
   block,
   showThinking,