From 677329427f32468c74b17f3ec47eeca4e05bec65 Mon Sep 17 00:00:00 2001
From: Neko <neko@ayaka.moe>
Date: Tue, 18 Aug 2026 20:28:55 +0800
Subject: [PATCH] fix(plugin-sdk-tamagotchi): allow nullable enum tool
 parameters (#2314)

---
 .../plugin-sdk-tamagotchi/src/index.test.ts   | 34 ++++++++++++++++++-
 .../plugin-sdk-tamagotchi/src/tools/index.ts  |  6 +++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/packages/plugin-sdk-tamagotchi/src/index.test.ts b/packages/plugin-sdk-tamagotchi/src/index.test.ts
index 66039bc47..6c15615f6 100644
--- a/packages/plugin-sdk-tamagotchi/src/index.test.ts
+++ b/packages/plugin-sdk-tamagotchi/src/index.test.ts
@@ -10,7 +10,7 @@ import type { HostDataRecord } from '@proj-airi/plugin-sdk/plugin-host'
 import type { ToolKitRuntime } from './tools'
 
 import { DisposableStore } from '@proj-airi/plugin-sdk'
-import { object, optional, string } from 'valibot'
+import { object, optional, picklist, string } from 'valibot'
 import { describe, expect, it, vi } from 'vitest'
 
 import {
@@ -731,6 +731,38 @@ describe('plugin-sdk-tamagotchi', () => {
     expect(parameters.properties.opening.type).toEqual(['string', 'null'])
   })
 
+  // ROOT CAUSE:
+  //
+  // The normalizer added null to an optional enum but kept type: "string".
+  // OpenAI rejected the schema because null does not satisfy the string type.
+  // The fix must allow null in both type and enum.
+  it('serializes optional enum tool fields as nullable enum properties', async () => {
+    const registerTool = vi.fn()
+    const tools = toolKit.createClient(createToolRuntime({
+      extensionId: 'airi-extension-chess',
+      sessionId: 'session-1',
+      moduleId: 'chess',
+      register: registerTool,
+      registerToolsetPrompt: vi.fn(),
+    }))
+
+    await tools.registerTool({
+      id: 'play_chess',
+      title: 'placeholder-title',
+      description: 'placeholder-description',
+      inputSchema: object({
+        airiSide: optional(picklist(['white', 'black'])),
+      }),
+      execute: async () => ({ ok: true }),
+    })
+
+    const parameters = registerTool.mock.calls[0]?.[0].tool.parameters
+
+    expect(parameters.required).toEqual(['airiSide'])
+    expect(parameters.properties.airiSide.type).toEqual(['string', 'null'])
+    expect(parameters.properties.airiSide.enum).toEqual(['white', 'black', null])
+  })
+
   /**
    * @example
    * expect(registerBinding).toHaveBeenCalledWith(expect.objectContaining({ moduleId: 'chess:board' }))
diff --git a/packages/plugin-sdk-tamagotchi/src/tools/index.ts b/packages/plugin-sdk-tamagotchi/src/tools/index.ts
index 758569724..bf3f9076b 100644
--- a/packages/plugin-sdk-tamagotchi/src/tools/index.ts
+++ b/packages/plugin-sdk-tamagotchi/src/tools/index.ts
@@ -171,7 +171,6 @@ function withNullableValue(schema: JsonSchema): JsonSchema {
 
   if (Array.isArray(next.enum)) {
     next.enum = next.enum.includes(null) ? next.enum : [...next.enum, null]
-    return next
   }
 
   if (Array.isArray(next.type)) {
@@ -184,6 +183,11 @@ function withNullableValue(schema: JsonSchema): JsonSchema {
     return next
   }
 
+  // An enum without a type already accepts every enum value, including null.
+  if (Array.isArray(next.enum)) {
+    return next
+  }
+
   next.anyOf = [...(next.anyOf ?? []), { type: 'null' }]
   return next
 }