fix: inherit dispatcher model for spawned sessions

src/server/sessions/spawnSessionTool.test.ts

@@ -2,18 +2,20 @@ import type { ExtensionContext } from "@earendil-works/pi-coding-agent";
 import { describe, expect, it, vi } from "vitest";
 import { createSpawnSessionToolDefinition } from "./spawnSessionTool.js";
 
-// The spawn tool's execute() never reads ctx, so an empty stub is sufficient.
-// eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub; execute() does not use ctx.
+// eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub with the minimal surface the tool reads.
 const ctx = {} as ExtensionContext;
+const dispatchModel = { provider: "anthropic", id: "claude-sonnet" };
+// eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- test stub with the minimal surface the tool reads.
+const ctxWithModel = { model: dispatchModel } as ExtensionContext;
 
 describe("createSpawnSessionToolDefinition", () => {
   it("passes the spawning cwd and params to the spawn callback and reports success", async () => {
     const spawn = vi.fn(() => Promise.resolve({ sessionId: "new-1", cwd: "/repos/a-feature" }));
     const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
 
-    const result = await tool.execute("call-1", { prompt: "do the thing", cwd: "/repos/a-feature" }, undefined, undefined, ctx);
+    const result = await tool.execute("call-1", { prompt: "do the thing", cwd: "/repos/a-feature" }, undefined, undefined, ctxWithModel);
 
-    expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", prompt: "do the thing", cwd: "/repos/a-feature" });
+    expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", prompt: "do the thing", cwd: "/repos/a-feature", model: dispatchModel });
     expect(result.details).toEqual({ sessionId: "new-1", cwd: "/repos/a-feature" });
     expect(result.content[0]).toMatchObject({ type: "text", text: "Started session new-1 in /repos/a-feature." });
   });
@@ -27,11 +29,20 @@ describe("createSpawnSessionToolDefinition", () => {
     expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", prompt: "continue", cwd: undefined });
   });
 
+  it("omits the inherited model when the dispatching session has no current model", async () => {
+    const spawn = vi.fn(() => Promise.resolve({ sessionId: "new-3", cwd: "/repos/a" }));
+    const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
+
+    await tool.execute("call-3", { prompt: "continue" }, undefined, undefined, ctx);
+
+    expect(spawn).toHaveBeenCalledWith({ spawningCwd: "/repos/a", prompt: "continue", cwd: undefined });
+  });
+
   it("propagates the spawn callback error so the agent loop reports it", async () => {
     const spawn = vi.fn(() => Promise.reject(new Error("cwd must be a workspace of this project. Allowed: /repos/a")));
     const tool = createSpawnSessionToolDefinition("/repos/a", { spawn });
 
-    await expect(tool.execute("call-3", { prompt: "x", cwd: "/elsewhere" }, undefined, undefined, ctx))
+    await expect(tool.execute("call-4", { prompt: "x", cwd: "/elsewhere" }, undefined, undefined, ctx))
       .rejects.toThrow("cwd must be a workspace of this project. Allowed: /repos/a");
   });
 });