fix(core): limit subagent nesting depth (#37124)

Co-authored-by: Dax <mail@thdxr.com>
2026-07-15 09:53:52 -05:00
parent 656f299017
commit 285d315b4e
4 changed files with 99 additions and 1 deletions
@@ -388,6 +388,86 @@ describe("tool.task", () => {
    }),
  )

+  it.instance("prevents subagents from launching subagents by default", () =>
+    Effect.gen(function* () {
+      const sessions = yield* Session.Service
+      const { chat, assistant } = yield* seed()
+      const child = yield* sessions.create({ parentID: chat.id, title: "child" })
+      const nestedAssistant = yield* sessions.updateMessage({
+        ...assistant,
+        id: MessageID.ascending(),
+        parentID: MessageID.ascending(),
+        sessionID: child.id,
+      })
+      const tool = yield* TaskTool
+      const def = yield* tool.init()
+      let asked = false
+
+      const exit = yield* def
+        .execute(
+          {
+            description: "inspect bug",
+            prompt: "look into the cache key path",
+            subagent_type: "general",
+          },
+          {
+            sessionID: child.id,
+            messageID: nestedAssistant.id,
+            agent: "general",
+            abort: new AbortController().signal,
+            extra: { promptOps: stubOps() },
+            messages: [],
+            metadata: () => Effect.void,
+            ask: () => Effect.sync(() => (asked = true)),
+          },
+        )
+        .pipe(Effect.exit)
+
+      expect(Exit.isFailure(exit)).toBe(true)
+      expect(asked).toBe(false)
+      expect(yield* sessions.children(child.id)).toHaveLength(0)
+    }),
+  )
+
+  it.instance(
+    "allows nested subagents up to the configured depth",
+    () =>
+      Effect.gen(function* () {
+        const sessions = yield* Session.Service
+        const { chat, assistant } = yield* seed()
+        const child = yield* sessions.create({ parentID: chat.id, title: "child" })
+        const nestedAssistant = yield* sessions.updateMessage({
+          ...assistant,
+          id: MessageID.ascending(),
+          parentID: MessageID.ascending(),
+          sessionID: child.id,
+        })
+        const tool = yield* TaskTool
+        const def = yield* tool.init()
+
+        const result = yield* def.execute(
+          {
+            description: "inspect bug",
+            prompt: "look into the cache key path",
+            subagent_type: "general",
+          },
+          {
+            sessionID: child.id,
+            messageID: nestedAssistant.id,
+            agent: "general",
+            abort: new AbortController().signal,
+            extra: { promptOps: stubOps() },
+            messages: [],
+            metadata: () => Effect.void,
+            ask: () => Effect.void,
+          },
+        )
+
+        expect((yield* sessions.get(result.metadata.sessionId)).parentID).toBe(child.id)
+      }),
+    { config: { subagent_depth: 2 } },
+  )
+
  it.instance(
    "execute shapes child permissions for task, todowrite, and primary tools",
    () =>