fix(agent-switch): make handoff durable and sync CLI TUI selection

src/tools/switch-agent/tools.test.ts

@@ -1,3 +1,5 @@
+/// <reference types="bun-types" />
+
 import { describe, test, expect, beforeEach } from "bun:test"
 import { createSwitchAgentTool } from "./tools"
 import { consumePendingSwitch, _resetForTesting as resetSwitch } from "../../features/agent-switch"
@@ -20,11 +22,36 @@ describe("switch_agent tool", () => {
     resetSession()
   })
 
+  function createToolWithMockClient(promptImpl?: () => Promise<unknown>) {
+    const client = {
+      session: {
+        promptAsync:
+          promptImpl ??
+          (async () => {
+            return undefined
+          }),
+        messages: async () => ({ data: [] }),
+      },
+    }
+
+    return createSwitchAgentTool({
+      client: client as unknown as {
+        session: {
+          promptAsync: (input: {
+            path: { id: string }
+            body: { agent: string; parts: Array<{ type: "text"; text: string }> }
+          }) => Promise<unknown>
+          messages: (input: { path: { id: string } }) => Promise<unknown>
+        }
+      },
+    })
+  }
+
   //#given valid atlas switch args
   //#when execute is called
   //#then it stores pending switch and updates session agent
   test("should queue switch to atlas", async () => {
-    const tool = createSwitchAgentTool()
+    const tool = createToolWithMockClient()
     const result = await tool.execute(
       { agent: "atlas", context: "Fix the auth bug based on council findings" },
       toolContext
@@ -46,7 +73,7 @@ describe("switch_agent tool", () => {
   //#when execute is called
   //#then it stores pending switch for prometheus
   test("should queue switch to prometheus", async () => {
-    const tool = createSwitchAgentTool()
+    const tool = createToolWithMockClient()
     const result = await tool.execute(
       { agent: "Prometheus", context: "Create a plan for the refactoring" },
       toolContext
@@ -63,7 +90,7 @@ describe("switch_agent tool", () => {
   //#when execute is called
   //#then it returns an error
   test("should reject invalid agent names", async () => {
-    const tool = createSwitchAgentTool()
+    const tool = createToolWithMockClient()
     const result = await tool.execute(
       { agent: "librarian", context: "Some context" },
       toolContext
@@ -78,7 +105,7 @@ describe("switch_agent tool", () => {
   //#when execute is called
   //#then it normalizes to lowercase
   test("should handle case-insensitive agent names", async () => {
-    const tool = createSwitchAgentTool()
+    const tool = createToolWithMockClient()
     await tool.execute(
       { agent: "ATLAS", context: "Fix things" },
       toolContext

src/tools/switch-agent/tools.ts

@@ -1,5 +1,6 @@
 import { tool, type ToolDefinition } from "@opencode-ai/plugin"
 import { setPendingSwitch } from "../../features/agent-switch"
+import { schedulePendingSwitchApply } from "../../features/agent-switch/scheduler"
 import { updateSessionAgent } from "../../features/claude-code-session-state"
 import type { SwitchAgentArgs } from "./types"
 
@@ -10,7 +11,26 @@ const DESCRIPTION =
 
 const ALLOWED_AGENTS = new Set(["atlas", "prometheus", "sisyphus", "hephaestus"])
 
-export function createSwitchAgentTool(): ToolDefinition {
+type SessionClient = {
+  session: {
+    prompt?: (input: {
+      path: { id: string }
+      body: { agent: string; parts: Array<{ type: "text"; text: string }> }
+    }) => Promise<unknown>
+    promptAsync: (input: {
+      path: { id: string }
+      body: { agent: string; parts: Array<{ type: "text"; text: string }> }
+    }) => Promise<unknown>
+    messages: (input: { path: { id: string } }) => Promise<unknown>
+    status?: () => Promise<unknown>
+  }
+}
+
+export function createSwitchAgentTool(args: {
+  client: SessionClient
+}): ToolDefinition {
+  const { client } = args
+
   return tool({
     description: DESCRIPTION,
     args: {
@@ -30,6 +50,10 @@ export function createSwitchAgentTool(): ToolDefinition {
 
       updateSessionAgent(toolContext.sessionID, agentName)
       setPendingSwitch(toolContext.sessionID, agentName, args.context)
+      schedulePendingSwitchApply({
+        sessionID: toolContext.sessionID,
+        client,
+      })
 
       return `Agent switch queued. Session will switch to ${agentName} when your turn completes.`
     },