diff --git a/src/tools/delegate-task/background-task.test.ts b/src/tools/delegate-task/background-task.test.ts
index f6ff49cb0..7b631f659 100644
--- a/src/tools/delegate-task/background-task.test.ts
+++ b/src/tools/delegate-task/background-task.test.ts
@@ -102,7 +102,7 @@ describeFn("executeBackgroundTask output/session metadata compatibility", () =>
     //#then - output and metadata should include canonical session linkage
     expectFn(result).toContain("<task_metadata>")
     expectFn(result).toContain("session_id: ses_sub_123")
-    expectFn(result).toContain("task_id: ses_sub_123")
+    expectFn(result).toContain("task_id: bg_resolved")
     expectFn(result).toContain("background_task_id: bg_resolved")
     expectFn(result).toContain("Background Task ID: bg_resolved")
     expectFn(metadataCalls).toHaveLength(1)
@@ -150,7 +150,7 @@ describeFn("executeBackgroundTask output/session metadata compatibility", () =>
 
     //#then - late session id still propagates to task metadata contract
     expectFn(result).toContain("session_id: ses_late_123")
-    expectFn(result).toContain("task_id: ses_late_123")
+    expectFn(result).toContain("task_id: bg_late")
     expectFn(result).toContain("background_task_id: bg_late")
     expectFn(metadataCalls).toHaveLength(1)
     expectFn(metadataCalls[0].metadata.sessionId).toBe("ses_late_123")
diff --git a/src/tools/delegate-task/background-task.ts b/src/tools/delegate-task/background-task.ts
index 1e0d2a697..04e0b1cb4 100644
--- a/src/tools/delegate-task/background-task.ts
+++ b/src/tools/delegate-task/background-task.ts
@@ -82,7 +82,7 @@ export async function executeBackgroundTask(
     }
 
     const taskMetadataBlock = sessionId
-      ? `\n\n<task_metadata>\nsession_id: ${sessionId}\ntask_id: ${sessionId}\nbackground_task_id: ${task.id}\n</task_metadata>`
+      ? `\n\n<task_metadata>\nsession_id: ${sessionId}\ntask_id: ${task.id}\nbackground_task_id: ${task.id}\n</task_metadata>`
       : ""
 
     return `Background task launched.