diff --git a/packages/core/src/tool/subagent.ts b/packages/core/src/tool/subagent.ts
index 78be0df690..ed487556ef 100644
--- a/packages/core/src/tool/subagent.ts
+++ b/packages/core/src/tool/subagent.ts
@@ -73,7 +73,7 @@ export const Plugin = {
       yield* runtime.session.synthetic({
         sessionID: parentID,
         text: `<subagent id="${childID}" state="${state}" description="${description}">\n${text}\n</subagent>`,
-        description: `Background agent ${state}: ${description}`,
+        description,
         metadata: { source: "subagent", childID, agent, state, description },
       })
     })
diff --git a/packages/core/test/tool-subagent.test.ts b/packages/core/test/tool-subagent.test.ts
index 2596e3058d..706fc67058 100644
--- a/packages/core/test/tool-subagent.test.ts
+++ b/packages/core/test/tool-subagent.test.ts
@@ -289,7 +289,7 @@ describe("SubagentTool", () => {
           const admission = Array.from(yield* Fiber.join(admitted))[0]
           expect(admission?.data.input.data.text).toContain(`<subagent id="${childID}" state="completed"`)
           expect(admission?.data.input.data).toMatchObject({
-            description: "Background agent completed: background review",
+            description: "background review",
             metadata: {
               source: "subagent",
               childID,