fix(desktop): prevent raw i18n key from leaking in slash command descriptions

getLocalizedFallbackCommands previously passed a constructed key to t()
without checking if the translation actually resolved. When the i18n
table lacked an entry, t() returned the raw key (e.g.
'slashCmd.clear.description'), which dosubot flagged in PR #593.

Fix: default to the static English description, only override when
t(key) returns a different string. Add two tests covering missing-key
fallback and partial-translation scenarios.

Co-Authored-By: qwen3.6-plus <QwenLM@claude-code-best.win>

desktop/src/components/chat/composerUtils.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest'
 import {
   filterSlashCommands,
   findSlashToken,
+  getLocalizedFallbackCommands,
   insertSlashTrigger,
   mergeSlashCommands,
   replaceSlashCommand,
@@ -143,4 +144,38 @@ describe('composerUtils', () => {
     expect(resolveSlashUiAction('context')).toEqual({ type: 'panel', command: 'context' })
     expect(resolveSlashUiAction('status')).toEqual({ type: 'panel', command: 'status' })
   })
+
+  it('falls back to the static English description when a translation key is missing', () => {
+    // Simulate an i18n t() function that returns the raw key for missing entries
+    // (this is what the real translate() does via zh[key] ?? en[key] ?? key).
+    const mockT = (key: string) => key
+
+    const commands = getLocalizedFallbackCommands(mockT)
+    const clearCmd = commands.find((c) => c.name === 'clear')
+    expect(clearCmd?.description).toBe('Clear conversation history')
+    expect(clearCmd?.description).not.toBe('slashCmd.clear.description')
+
+    // Verify every command renders a human-readable description, never a raw key
+    for (const cmd of commands) {
+      expect(cmd.description).not.toMatch(/^slashCmd\./)
+    }
+  })
+
+  it('uses the localized description when the translation key resolves to a real string', () => {
+    const mockT = (key: string) => {
+      const map: Record<string, string> = {
+        'slashCmd.clear.description': '清空会话历史',
+      }
+      return map[key] ?? key
+    }
+
+    const commands = getLocalizedFallbackCommands(mockT)
+    const clearCmd = commands.find((c) => c.name === 'clear')
+    expect(clearCmd?.description).toBe('清空会话历史')
+
+    // A command without a translated key should still fall back to English
+    const mcpCmd = commands.find((c) => c.name === 'mcp')
+    expect(mcpCmd?.description).toBe('Open available MCP tools for the current chat context')
+    expect(mcpCmd?.description).not.toBe('slashCmd.mcp.description')
+  })
 })

desktop/src/components/chat/composerUtils.ts

@@ -79,13 +79,34 @@ export const FALLBACK_SLASH_COMMANDS: SlashCommandOption[] = [
   { name: 'vim', description: 'Toggle vim editing mode' },
 ]
 
-/** Build localized fallback commands using the current locale */
+/** Build localized fallback commands using the current locale.
+ *
+ * Resolution order for each command's description:
+ *   1. Localized string from the i18n table (zh -> en) when a key is registered.
+ *   2. The static English description shipped in FALLBACK_SLASH_COMMANDS.
+ *
+ * This guarantees we never render a raw key (e.g. "slashCmd.foo.description")
+ * in the UI even if a command is missing from SLASH_CMD_DESCRIPTION_KEYS or
+ * its translation entry is absent.
+ */
 export function getLocalizedFallbackCommands(t: (key: TranslationKey) => string): SlashCommandOption[] {
-  return FALLBACK_SLASH_COMMANDS.map((cmd) => ({
-    name: cmd.name,
-    description: t(SLASH_CMD_DESCRIPTION_KEYS[cmd.name] ?? ('slashCmd.' + cmd.name + '.description' as TranslationKey)),
-    ...(cmd.argumentHint && { argumentHint: cmd.argumentHint }),
-  }))
+  return FALLBACK_SLASH_COMMANDS.map((cmd) => {
+    const key = SLASH_CMD_DESCRIPTION_KEYS[cmd.name]
+    let description = cmd.description
+    if (key) {
+      const translated = t(key)
+      // i18n returns the key itself when no translation is found; fall back to
+      // the static English description in that case.
+      if (translated && translated !== key) {
+        description = translated
+      }
+    }
+    return {
+      name: cmd.name,
+      description,
+      ...(cmd.argumentHint && { argumentHint: cmd.argumentHint }),
+    }
+  })
 }
 
 export type SlashCommandOption = {