feat: model Codex subagent result events

frontend/src/lib/api/types/core.ts

@@ -41,6 +41,19 @@ export interface ProjectInfo {
   session_count: number;
 }
 
+/** Matches Go ToolResultEvent struct in internal/db/messages.go */
+export interface ToolResultEvent {
+  tool_use_id?: string;
+  agent_id?: string;
+  subagent_session_id?: string;
+  source: string;
+  status: string;
+  content: string;
+  content_length: number;
+  timestamp?: string;
+  event_index: number;
+}
+
 /** Matches Go ToolCall struct in internal/db/messages.go */
 export interface ToolCall {
   tool_name: string;
@@ -51,6 +64,7 @@ export interface ToolCall {
   result_content_length?: number;
   result_content?: string;
   subagent_session_id?: string;
+  result_events?: ToolResultEvent[];
 }
 
 /** Matches Go Message struct in internal/db/messages.go */

frontend/src/lib/components/content/ToolBlock.svelte

@@ -20,10 +20,13 @@
   let { content, label, toolCall, highlightQuery = "", isCurrentHighlight = false }: Props = $props();
   let userCollapsed: boolean = $state(true);
   let userOutputCollapsed: boolean = $state(true);
+  let userHistoryCollapsed: boolean = $state(true);
   let userOverride: boolean = $state(false);
   let userOutputOverride: boolean = $state(false);
+  let userHistoryOverride: boolean = $state(false);
   let searchExpandedInput: boolean = $state(false);
   let searchExpandedOutput: boolean = $state(false);
+  let searchExpandedHistory: boolean = $state(false);
   let prevQuery: string = "";
 
   // Auto-expand when a search match exists in input or output
@@ -41,14 +44,19 @@
     const inputText = (
       taskPrompt ?? content ?? fallbackContent ?? ""
     ).toLowerCase();
+    const historyText = (
+      toolCall?.result_events?.map((event) => event.content).join("\n\n") ?? ""
+    ).toLowerCase();
     const outputText = (
-      toolCall?.result_content ?? ""
+      [toolCall?.result_content ?? "", historyText].filter(Boolean).join("\n\n")
     ).toLowerCase();
     searchExpandedInput = inputText.includes(q);
     searchExpandedOutput = outputText.includes(q);
+    searchExpandedHistory = historyText.includes(q);
     if (hq !== prevQuery) {
       userOverride = false;
       userOutputOverride = false;
+      userHistoryOverride = false;
       prevQuery = hq;
     }
   });
@@ -63,6 +71,11 @@
       : searchExpandedOutput ? false
       : userOutputCollapsed,
   );
+  let historyCollapsed = $derived(
+    userHistoryOverride ? userHistoryCollapsed
+      : searchExpandedHistory ? false
+      : userHistoryCollapsed,
+  );
 
   let outputPreviewLine = $derived.by(() => {
     const rc = toolCall?.result_content;
@@ -71,6 +84,14 @@
     return (nl === -1 ? rc : rc.slice(0, nl)).slice(0, 100);
   });
 
+  let resultEvents = $derived(toolCall?.result_events ?? []);
+
+  let historyPreviewLine = $derived.by(() => {
+    const last = resultEvents[resultEvents.length - 1];
+    if (!last) return "";
+    return `${last.status}: ${last.content.split("\n")[0]}`.slice(0, 100);
+  });
+
   /** Parsed input parameters from structured tool call data */
   let inputParams = $derived.by(() => {
     if (!toolCall?.input_json) return null;
@@ -247,6 +268,51 @@
         <pre class="tool-content output-content" use:applyHighlight={{ q: highlightQuery, current: isCurrentHighlight, content: toolCall.result_content }}>{@html escapeHTML(toolCall.result_content)}</pre>
       {/if}
     {/if}
+    {#if resultEvents.length > 0}
+      <button
+        class="history-header"
+        onclick={(e) => {
+          e.stopPropagation();
+          const sel = window.getSelection();
+          if (sel && sel.toString().length > 0) return;
+          userHistoryCollapsed = !userHistoryCollapsed;
+          userHistoryOverride = true;
+        }}
+      >
+        <span class="tool-chevron" class:open={!historyCollapsed}>
+          &#9656;
+        </span>
+        <span class="output-label">history</span>
+        {#if historyCollapsed && historyPreviewLine}
+          <span class="tool-preview">{historyPreviewLine}</span>
+        {/if}
+      </button>
+      {#if !historyCollapsed}
+        <div class="result-history">
+          {#each resultEvents as event (event.event_index)}
+            <div class="result-event">
+              <div class="result-event-meta">
+                <span class="meta-tag">
+                  <span class="meta-label">status:</span>
+                  {event.status}
+                </span>
+                <span class="meta-tag">
+                  <span class="meta-label">source:</span>
+                  {event.source}
+                </span>
+                {#if event.agent_id}
+                  <span class="meta-tag">
+                    <span class="meta-label">agent:</span>
+                    {event.agent_id}
+                  </span>
+                {/if}
+              </div>
+              <pre class="tool-content output-content history-content" use:applyHighlight={{ q: highlightQuery, current: isCurrentHighlight, content: event.content }}>{@html escapeHTML(event.content)}</pre>
+            </div>
+          {/each}
+        </div>
+      {/if}
+    {/if}
   {/if}
   {#if subagentSessionId}
     <SubagentInline sessionId={subagentSessionId} />
@@ -364,6 +430,26 @@
     color: var(--text-primary);
   }
 
+  .history-header {
+    display: flex;
+    align-items: center;
+    gap: 6px;
+    padding: 5px 10px;
+    width: 100%;
+    text-align: left;
+    font-size: 12px;
+    color: var(--text-secondary);
+    min-width: 0;
+    border-top: 1px solid var(--border-muted);
+    transition: background 0.1s;
+    user-select: text;
+  }
+
+  .history-header:hover {
+    background: var(--bg-surface-hover);
+    color: var(--text-primary);
+  }
+
   .output-label {
     font-family: var(--font-mono);
     font-weight: 500;
@@ -377,4 +463,24 @@
     max-height: 300px;
     overflow-y: auto;
   }
+
+  .result-history {
+    border-top: 1px solid var(--border-muted);
+  }
+
+  .result-event + .result-event {
+    border-top: 1px solid var(--border-muted);
+  }
+
+  .result-event-meta {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 6px;
+    padding: 6px 14px 0;
+  }
+
+  .history-content {
+    border-top: 0;
+    margin-top: 0;
+  }
 </style>

frontend/src/lib/components/content/ToolBlock.test.ts

@@ -133,6 +133,77 @@ describe("ToolBlock output section", () => {
     expect(preview).not.toBeNull();
     expect(preview!.textContent).toBe("first line");
   });
+
+  it("renders history after expanding the tool block when result_events are set", async () => {
+    const toolCall: ToolCall = {
+      tool_name: "wait",
+      category: "Other",
+      result_content: "latest summary",
+      result_events: [
+        {
+          source: "wait_output",
+          status: "completed",
+          content: "Finished successfully",
+          content_length: 21,
+          agent_id: "agent-1",
+          event_index: 0,
+        },
+      ],
+    };
+    component = mount(ToolBlock, {
+      target: document.body,
+      props: { content: "some input", toolCall },
+    });
+    await tick();
+
+    expect(document.querySelector(".history-header")).toBeNull();
+
+    document.querySelector<HTMLButtonElement>(".tool-header")!.click();
+    await tick();
+
+    expect(document.querySelector(".history-header")).not.toBeNull();
+  });
+
+  it("expands event history and shows chronological event content", async () => {
+    const toolCall: ToolCall = {
+      tool_name: "wait",
+      category: "Other",
+      result_content: "agent-a:\nFirst finished\n\nagent-b:\nSecond finished",
+      result_events: [
+        {
+          source: "wait_output",
+          status: "completed",
+          content: "First finished",
+          content_length: 14,
+          agent_id: "agent-a",
+          event_index: 0,
+        },
+        {
+          source: "subagent_notification",
+          status: "completed",
+          content: "Second finished",
+          content_length: 15,
+          agent_id: "agent-b",
+          event_index: 1,
+        },
+      ],
+    };
+    component = mount(ToolBlock, {
+      target: document.body,
+      props: { content: "some input", toolCall },
+    });
+    await tick();
+
+    document.querySelector<HTMLButtonElement>(".tool-header")!.click();
+    await tick();
+    document.querySelector<HTMLButtonElement>(".history-header")!.click();
+    await tick();
+
+    const historyEntries = Array.from(document.querySelectorAll(".history-content"));
+    expect(historyEntries).toHaveLength(2);
+    expect(historyEntries[0].textContent).toBe("First finished");
+    expect(historyEntries[1].textContent).toBe("Second finished");
+  });
 });
 
 describe("ToolBlock fallback content", () => {

internal/db/db.go

@@ -23,7 +23,7 @@ import (
 // formatting changes). Old databases with a lower user_version
 // trigger a non-destructive re-sync (mtime reset + skip cache
 // clear) so existing session data is preserved.
-const dataVersion = 6
+const dataVersion = 8
 
 //go:embed schema.sql
 var schemaSQL string