feat(config): add custom_agents overrides and strict agent validation

src/tools/delegate-task/subagent-resolver.test.ts

@@ -79,4 +79,56 @@ describe("resolveSubagentExecution", () => {
       error: "network timeout",
     })
   })
+
+  test("uses inherited model for custom agents without explicit model", async () => {
+    //#given
+    const args = createBaseArgs({ subagent_type: "translator" })
+    const executorCtx = createExecutorContext(async () => ({
+      data: [{ name: "translator", mode: "subagent" }],
+    }))
+
+    //#when
+    const result = await resolveSubagentExecution(
+      args,
+      executorCtx,
+      "sisyphus",
+      "deep",
+      "openai/gpt-5.3-codex",
+      "anthropic/claude-opus-4-6",
+    )
+
+    //#then
+    expect(result.error).toBeUndefined()
+    expect(result.agentToUse).toBe("translator")
+    expect(result.categoryModel).toEqual({
+      providerID: "openai",
+      modelID: "gpt-5.3-codex",
+    })
+  })
+
+  test("uses system default model when inherited model is unavailable", async () => {
+    //#given
+    const args = createBaseArgs({ subagent_type: "translator" })
+    const executorCtx = createExecutorContext(async () => ({
+      data: [{ name: "translator", mode: "subagent" }],
+    }))
+
+    //#when
+    const result = await resolveSubagentExecution(
+      args,
+      executorCtx,
+      "sisyphus",
+      "deep",
+      undefined,
+      "anthropic/claude-opus-4-6",
+    )
+
+    //#then
+    expect(result.error).toBeUndefined()
+    expect(result.agentToUse).toBe("translator")
+    expect(result.categoryModel).toEqual({
+      providerID: "anthropic",
+      modelID: "claude-opus-4-6",
+    })
+  })
 })