fix(server): deleting a thread also removes its agent preview recordings (#29853)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: saphid

apps/server/src/attachmentStore.ts

@@ -4,7 +4,11 @@ import * as NodeFS from "node:fs";
 import * as NodePath from "node:path";
 
 import type { ChatAttachment } from "@t3tools/contracts";
-import { htmlRenderFromToolItem, mcpAppFromToolItem } from "@t3tools/shared/toolOutput";
+import {
+  htmlRenderFromToolItem,
+  mcpAppFromToolItem,
+  previewRecordingIdFromToolItem,
+} from "@t3tools/shared/toolOutput";
 
 import {
   normalizeAttachmentRelativePath,
@@ -133,7 +137,9 @@ export function threadHtmlRenderAttachmentIds(
   if (segment === null) return [];
   return Array.from(items).flatMap((item) => {
     const attachmentId =
-      htmlRenderFromToolItem(item)?.attachmentId ?? mcpAppFromToolItem(item)?.attachmentId;
+      htmlRenderFromToolItem(item)?.attachmentId ??
+      mcpAppFromToolItem(item)?.attachmentId ??
+      previewRecordingIdFromToolItem(item);
     return attachmentId !== undefined &&
       parseThreadSegmentFromAttachmentId(attachmentId) === segment
       ? [attachmentId]

apps/server/src/orchestration-v2/ProjectionStore.ts

@@ -5504,7 +5504,8 @@ export const layer: Layer.Layer<ProjectionStoreV2, never, SqlClient.SqlClient> =
       FROM orchestration_v2_projection_turn_items
       WHERE thread_id = ${threadId}
         AND type = 'dynamic_tool'
-        AND (payload_json LIKE '%htmlRender%' OR payload_json LIKE ${`%${MCP_APP_OUTPUT_KEY}%`})
+        AND (payload_json LIKE '%htmlRender%' OR payload_json LIKE ${`%${MCP_APP_OUTPUT_KEY}%`}
+          OR payload_json LIKE '%preview_recording_stop%')
     `,
         sql<{ id: string }>`
       SELECT DISTINCT json_extract(attachment.value, '$.id') AS id

apps/server/src/orchestration-v2/TurnStartReads.test.ts

@@ -406,11 +406,30 @@ it.effect.each(["sqlite"] as const)(
           },
         },
       });
+      const recordingId = "thread-completion-reads-0b9f6c1e-3c1d-4f7a-9d2e-5a6b7c8d9e0f-webm";
+      yield* store.apply({
+        id: EventId.make("attachment:recording-event"),
+        type: "turn-item.updated",
+        threadId,
+        runId: oldRunId,
+        occurredAt: now,
+        payload: {
+          ...item,
+          id: TurnItemId.make("attachment:recording"),
+          type: "dynamic_tool",
+          toolName: "mcp__t3-code__preview_recording_stop",
+          input: {},
+          output: [
+            { type: "text", text: JSON.stringify({ id: recordingId, mimeType: "video/webm" }) },
+          ],
+        },
+      });
       assert.deepEqual((yield* store.getThreadAttachmentIds(threadId)).toSorted(), [
         "answer-document",
         "answer-image",
         "attachment:old",
         "message-file",
+        recordingId,
       ]);
     }).pipe(Effect.provide(layerDatabase)),
 );

packages/shared/src/toolOutput.ts

@@ -191,6 +191,21 @@ export function htmlRenderFromToolItem(item: {
   return output?.isError ? undefined : output?.htmlRender;
 }
 
+/** The thread-owned file `preview_recording_stop` stored for the agent. */
+export function previewRecordingIdFromToolItem(item: {
+  readonly toolName: string | null | undefined;
+  readonly output?: unknown;
+}): string | undefined {
+  if (resolveT3McpToolId(item.toolName) !== "preview_recording_stop") return undefined;
+  const budget: ResultReadBudget = {
+    remainingBytes: MAX_PARSED_BYTES,
+    remainingNodes: MAX_ENVELOPE_NODES,
+    exceeded: false,
+  };
+  const result = readResult(item.output, budget);
+  return result.failed || budget.exceeded ? undefined : boundedId(result.data?.id);
+}
+
 /** Accept app references only when server and tool match the item, so tools cannot impersonate another app source. */
 export function mcpAppFromToolItem(item: {
   readonly toolName: string | null | undefined;