From f8398dbec3acdeadbebe71f9109efd50a05c9ec0 Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Sat, 4 Apr 2026 19:33:11 +0900
Subject: [PATCH] fix(delegate-task): restrict task-callable agent modes

---
 .../delegate-task/subagent-resolver.test.ts   | 35 +++++++++++++++++++
 src/tools/delegate-task/subagent-resolver.ts  | 21 ++++-------
 2 files changed, 42 insertions(+), 14 deletions(-)

diff --git a/src/tools/delegate-task/subagent-resolver.test.ts b/src/tools/delegate-task/subagent-resolver.test.ts
index 4205a6b66..7f87f8531 100644
--- a/src/tools/delegate-task/subagent-resolver.test.ts
+++ b/src/tools/delegate-task/subagent-resolver.test.ts
@@ -85,6 +85,41 @@ describe("resolveSubagentExecution", () => {
     })
   })
 
+  test("hides primary agents from task delegation lookups", async () => {
+    //#given
+    const args = createBaseArgs({ subagent_type: "sisyphus" })
+    const executorCtx = createExecutorContext(async () => ([
+      { name: "sisyphus", mode: "primary" },
+      { name: "oracle", mode: "subagent" },
+      { name: "metis", mode: "all" },
+    ]))
+
+    //#when
+    const result = await resolveSubagentExecution(args, executorCtx, "sisyphus", "deep")
+
+    //#then
+    expect(result.agentToUse).toBe("")
+    expect(result.categoryModel).toBeUndefined()
+    expect(result.error).toBe('Unknown agent: "sisyphus". Available agents: metis, oracle')
+  })
+
+  test("requires explicit all or subagent mode for task-callable agents", async () => {
+    //#given
+    const args = createBaseArgs({ subagent_type: "custom-worker" })
+    const executorCtx = createExecutorContext(async () => ([
+      { name: "custom-worker" },
+      { name: "oracle", mode: "subagent" },
+    ]))
+
+    //#when
+    const result = await resolveSubagentExecution(args, executorCtx, "sisyphus", "deep")
+
+    //#then
+    expect(result.agentToUse).toBe("")
+    expect(result.categoryModel).toBeUndefined()
+    expect(result.error).toBe('Unknown agent: "custom-worker". Available agents: oracle')
+  })
+
   test("normalizes matched agent model string before returning categoryModel", async () => {
     //#given
     const cacheSpy = spyOn(connectedProvidersCache, "readProviderModelsCache").mockReturnValue({
diff --git a/src/tools/delegate-task/subagent-resolver.ts b/src/tools/delegate-task/subagent-resolver.ts
index 242bcdac1..f5a255c70 100644
--- a/src/tools/delegate-task/subagent-resolver.ts
+++ b/src/tools/delegate-task/subagent-resolver.ts
@@ -16,6 +16,8 @@ import { resolveModelForDelegateTask } from "./model-selection"
 import { fuzzyMatchModel } from "../../shared/model-availability"
 import type { CategoryConfig } from "../../config/schema"
 
+type AgentMode = "subagent" | "primary" | "all" | undefined
+
 function applyCategoryParams(
   base: DelegatedModelConfig,
   config: CategoryConfig | undefined,
@@ -85,7 +87,7 @@ Create the work plan directly - that's your job as the planning agent.`,
       preferResponseOnMissingData: true,
     })
 
-    const callableAgents = agents.filter((a) => a.mode !== "primary")
+    const callableAgents = agents.filter((agent) => isTaskCallableAgentMode(agent.mode))
 
     const resolvedDisplayName = getAgentDisplayName(agentToUse)
     const matchedAgent = callableAgents.find(
@@ -93,19 +95,6 @@ Create the work plan directly - that's your job as the planning agent.`,
         || agent.name.toLowerCase() === resolvedDisplayName.toLowerCase()
     )
     if (!matchedAgent) {
-      const isPrimaryAgent = agents
-        .filter((a) => a.mode === "primary")
-        .find((agent) => agent.name.toLowerCase() === agentToUse.toLowerCase()
-          || agent.name.toLowerCase() === resolvedDisplayName.toLowerCase())
-
-      if (isPrimaryAgent) {
-        return {
-          agentToUse: "",
-          categoryModel: undefined,
-    error: `Cannot call primary agent "${isPrimaryAgent.name}" via task. Primary agents are top-level orchestrators.`,
-        }
-      }
-
       const availableAgents = callableAgents
         .map((a) => a.name)
         .sort()
@@ -239,3 +228,7 @@ Create the work plan directly - that's your job as the planning agent.`,
 
   return { agentToUse, categoryModel, fallbackChain }
 }
+
+function isTaskCallableAgentMode(mode: AgentMode): boolean {
+  return mode === "all" || mode === "subagent"
+}