Explain the mode required to create agents on another provider (#8483)

* fix(server): say when create_agent needs an explicit mode

* test(server): verify cross-provider mode discovery through the daemon

Exercise the MCP contract, refusal without a child, provider inspection, and explicit-mode creation through the public daemon interfaces. Qualify unattended advice because targets without an unattended mode still require an explicit choice.

Co-authored-by: Noah <noahguerin20@gmail.com>

* test(server): run mode discovery in the integration suite

The unit command excludes E2E files, and CI integration uses an explicit list. Add the cross-provider MCP regression to that existing list so CI exercises its guidance, refusal, discovery, and retry assertions.

---------

Co-authored-by: Noah <noahguerin20@gmail.com>
Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>

packages/server/package.json

@@ -89,7 +89,7 @@
     "speech:transcribe:local": "tsx scripts/transcribe-local-wav.ts",
     "test": "npm run test:unit && npm run test:integration",
     "test:unit": "vitest run --fileParallelism --exclude \"**/*.e2e.test.ts\"",
-    "test:integration": "vitest run --maxWorkers=1 src/server/git-filename-diffs.e2e.test.ts src/server/daemon-e2e/checkout-diff-content.e2e.test.ts src/server/daemon-e2e/filesystem.e2e.test.ts src/server/daemon-e2e/file-download.e2e.test.ts src/server/daemon-e2e/cli-logs-follow.e2e.test.ts src/server/creation/creation.e2e.test.ts src/server/daemon-e2e/creation-status.e2e.test.ts src/server/daemon-e2e/terminal-workspace-sdk.e2e.test.ts src/server/daemon-e2e/terminal-worker-lifecycle.e2e.test.ts src/server/workspace-create-worktree-source.e2e.test.ts src/server/daemon-e2e/models.e2e.test.ts src/server/daemon-e2e/live-preferences.e2e.test.ts src/server/daemon-e2e/oversized-message.e2e.test.ts src/server/agent/model-catalog.e2e.test.ts src/server/plugins/plugin-paseo-api.e2e.test.ts src/server/plugins/usage-sources.e2e.test.ts src/server/plugins/lifecycle.e2e.test.ts src/server/connected-hosts/hosts.e2e.test.ts src/server/owned-subscriptions.e2e.test.ts && vitest run --maxWorkers=1 src/server/agent/providers/omp/history.e2e.test.ts src/server/daemon-e2e/git-operations.e2e.test.ts src/server/session.create-agent-worktree-autoarchive.e2e.test.ts src/server/agent/providers/opencode-bridge.local.e2e.test.ts src/server/daemon-e2e/relay-transport.e2e.test.ts -t \"merges into|creates a worktree and auto-archives both|versioned runtime|oversized attachments|connected hosts|password-protected daemon refuses|replays selected OMP history\"",
+    "test:integration": "vitest run --maxWorkers=1 src/server/git-filename-diffs.e2e.test.ts src/server/daemon-e2e/checkout-diff-content.e2e.test.ts src/server/daemon-e2e/create-agent-mode.e2e.test.ts src/server/daemon-e2e/filesystem.e2e.test.ts src/server/daemon-e2e/file-download.e2e.test.ts src/server/daemon-e2e/cli-logs-follow.e2e.test.ts src/server/creation/creation.e2e.test.ts src/server/daemon-e2e/creation-status.e2e.test.ts src/server/daemon-e2e/terminal-workspace-sdk.e2e.test.ts src/server/daemon-e2e/terminal-worker-lifecycle.e2e.test.ts src/server/workspace-create-worktree-source.e2e.test.ts src/server/daemon-e2e/models.e2e.test.ts src/server/daemon-e2e/live-preferences.e2e.test.ts src/server/daemon-e2e/oversized-message.e2e.test.ts src/server/agent/model-catalog.e2e.test.ts src/server/plugins/plugin-paseo-api.e2e.test.ts src/server/plugins/usage-sources.e2e.test.ts src/server/plugins/lifecycle.e2e.test.ts src/server/connected-hosts/hosts.e2e.test.ts src/server/owned-subscriptions.e2e.test.ts && vitest run --maxWorkers=1 src/server/agent/providers/omp/history.e2e.test.ts src/server/daemon-e2e/git-operations.e2e.test.ts src/server/session.create-agent-worktree-autoarchive.e2e.test.ts src/server/agent/providers/opencode-bridge.local.e2e.test.ts src/server/daemon-e2e/relay-transport.e2e.test.ts -t \"merges into|creates a worktree and auto-archives both|versioned runtime|oversized attachments|connected hosts|password-protected daemon refuses|replays selected OMP history\"",
     "test:hub-cli-contract": "vitest run --maxWorkers=1 src/server/hub/hub-cli-contract.test.ts",
     "test:integration:all": "npm run test:e2e",
     "test:integration:real": "vitest run real.e2e.test.ts",

packages/server/src/server/agent/create-agent-mode.test.ts

@@ -78,7 +78,7 @@ describe("resolveAndValidateCreateAgentMode", () => {
         availableModes: OPENCODE_MODES,
       }),
     ).toThrow(
-      "cannot inherit mode 'bypassPermissions' from caller (provider 'claude') for new agent (provider 'opencode'). Pass an explicit mode. Available modes for 'opencode': build, plan",
+      "cannot inherit mode 'bypassPermissions' from caller (provider 'claude') for new agent (provider 'opencode'). Pass an explicit mode in settings.modeId. Available modes for 'opencode': build, plan",
     );
   });
 
@@ -92,7 +92,7 @@ describe("resolveAndValidateCreateAgentMode", () => {
         availableModes: CODEX_MODES,
       }),
     ).toThrow(
-      "cannot inherit mode '<none>' from caller (provider 'opencode') for new agent (provider 'codex'). Pass an explicit mode. Available modes for 'codex': auto, full-access",
+      "cannot inherit mode '<none>' from caller (provider 'opencode') for new agent (provider 'codex'). Pass an explicit mode in settings.modeId. Available modes for 'codex': auto, full-access",
     );
   });
 
@@ -180,7 +180,7 @@ describe("resolveAndValidateCreateAgentMode", () => {
         targetUnattendedMode: "full-access",
       }),
     ).toThrow(
-      "cannot inherit mode 'default' from caller (provider 'claude') for new agent (provider 'codex'). Pass an explicit mode. Available modes for 'codex': auto, full-access",
+      "cannot inherit mode 'default' from caller (provider 'claude') for new agent (provider 'codex'). Pass an explicit mode in settings.modeId. Available modes for 'codex': auto, full-access",
     );
   });
 
@@ -195,7 +195,7 @@ describe("resolveAndValidateCreateAgentMode", () => {
         targetUnattendedMode: undefined,
       }),
     ).toThrow(
-      "cannot inherit mode 'bypassPermissions' from caller (provider 'claude') for new agent (provider 'zai-custom'). Pass an explicit mode. Available modes for 'zai-custom': unknown",
+      "cannot inherit mode 'bypassPermissions' from caller (provider 'claude') for new agent (provider 'zai-custom'). Pass an explicit mode in settings.modeId. Available modes for 'zai-custom': unknown",
     );
   });
 

packages/server/src/server/agent/create-agent-mode.ts

@@ -77,7 +77,7 @@ export function resolveAndValidateCreateAgentMode(
   }
 
   throw new Error(
-    `cannot inherit mode '${formatCreateConfigParentMode(parent)}' from ${formatCreateConfigParentSource(parent)} for new agent (provider '${targetProvider}'). Pass an explicit mode. Available modes for '${targetProvider}': ${listModes(availableModes)}`,
+    `cannot inherit mode '${formatCreateConfigParentMode(parent)}' from ${formatCreateConfigParentSource(parent)} for new agent (provider '${targetProvider}'). Pass an explicit mode in settings.modeId. Available modes for '${targetProvider}': ${listModes(availableModes)}`,
   );
 }
 

packages/server/src/server/agent/tools/paseo-tools.ts

@@ -1590,7 +1590,7 @@ function createToolCatalog(
     {
       title: "Create agent",
       description:
-        "Create an agent. Agent-scoped creation defaults to your workspace and creates your subagent. Top-level creation without workspaceId creates a new local workspace. Requires provider/model (for example codex/gpt-5.4) and an initial prompt. Do not guess; call list_providers and list_models first if uncertain.",
+        "Create an agent. Agent-scoped creation defaults to your workspace and creates your subagent. Top-level creation without workspaceId creates a new local workspace. Requires provider/model (for example codex/gpt-5.4) and an initial prompt. For a different provider, set settings.modeId from inspect_provider; omission is accepted for targets with no modes and for unattended execution supported by the target. Do not guess; call list_providers and list_models first if uncertain.",
       inputSchema: createAgentInputSchema,
       outputSchema: {
         agentId: z.string(),

packages/server/src/server/daemon-e2e/create-agent-mode.e2e.test.ts

@@ -0,0 +1,67 @@
+import { mkdir, mkdtemp, rm } from "node:fs/promises";
+import path from "node:path";
+import { Client } from "@modelcontextprotocol/sdk/client/index.js";
+import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";
+import { expect, test } from "vitest";
+import { createDaemonTestContext } from "../test-utils/index.js";
+
+test("an attended MCP caller can discover and supply a cross-provider child mode", async () => {
+  const artifacts = path.join(process.cwd(), ".artifacts");
+  await mkdir(artifacts, { recursive: true });
+  const root = await mkdtemp(path.join(artifacts, "create-agent-mode-"));
+  const ctx = await createDaemonTestContext({ paseoHomeRoot: root, mcpEnabled: true });
+  const mcp = new Client({ name: "mode-contract-test", version: "1" });
+  try {
+    const parent = await ctx.client.createAgent({
+      provider: "claude",
+      cwd: root,
+      modeId: "default",
+      title: "Attended parent",
+    });
+    await mcp.connect(
+      new StreamableHTTPClientTransport(
+        new URL(`http://127.0.0.1:${ctx.daemon.port}/mcp/agents?callerAgentId=${parent.id}`),
+      ),
+    );
+    const { tools } = await mcp.listTools();
+    const create = tools.find((tool) => tool.name === "create_agent");
+    expect.soft(create?.description).toContain("settings.modeId");
+
+    const args = {
+      provider: "codex/gpt-5.4-mini",
+      title: "Cross-provider child",
+      initialPrompt: "Reply with OK",
+    };
+    const refused = await mcp.callTool({ name: "create_agent", arguments: args });
+    expect(refused.isError).toBe(true);
+    expect.soft(refused.content).toEqual([
+      expect.objectContaining({
+        type: "text",
+        text: expect.stringContaining("Pass an explicit mode in settings.modeId"),
+      }),
+    ]);
+    expect((await ctx.client.fetchAgents({ subscribe: {} })).entries).toHaveLength(1);
+
+    const inspected = await mcp.callTool({
+      name: "inspect_provider",
+      arguments: { provider: "codex" },
+    });
+    expect(inspected.isError).not.toBe(true);
+    expect(inspected.structuredContent).toMatchObject({
+      modes: expect.arrayContaining([expect.objectContaining({ id: "auto" })]),
+    });
+    const created = await mcp.callTool({
+      name: "create_agent",
+      arguments: { ...args, settings: { modeId: "auto" } },
+    });
+    expect(created.isError).not.toBe(true);
+    expect(created.structuredContent).toMatchObject({ type: "codex", currentModeId: "auto" });
+    const childId = (created.structuredContent as { agentId: string }).agentId;
+    expect((await ctx.client.fetchAgent(childId))?.agent.currentModeId).toBe("auto");
+    expect((await ctx.client.waitForFinish(childId, 5000)).status).toBe("idle");
+  } finally {
+    await mcp.close();
+    await ctx.cleanup();
+    await rm(root, { recursive: true, force: true });
+  }
+}, 30_000);