Function isMCPSupportedWBCountryCode

isMCPSupportedWBCountryCode(code: unknown): boolean
Guard: returns true if code is safe to pass to any worldbank-mcp@1.0.1 tool (get-country-info, get-economic-data, get-social-data, get-health-data, get-education-data), and false if the code would cause the MCP server to return Error: Country not found — which is handled as an empty-data fallback upstream and therefore fails silently.

The guard accepts any 2-letter (ISO 3166-1 alpha-2) or 3-letter (alpha-3) country code and rejects:
- The 8 aggregate codes listed in WB_AGGREGATE_LABELS (EUU, EMU, OED, WLD, ECS, NAC, EAS, SSF). These work only against the raw WB REST API — use the IMF client for EU-aggregate economic context.
- The informal alias UK — use GB instead.
- Empty, non-string, or malformed inputs.
The guard is case-insensitive: 'euu' and 'EUU' both return false, 'de' and 'DE' both return true.
Parameters
- code: unknown
  Country code candidate
Returns boolean
true when the code is a per-country identifier accepted by the MCP server, false when it is an aggregate, an informal alias, or invalid
Example
```
isMCPSupportedWBCountryCode('DE');   // → true
isMCPSupportedWBCountryCode('DEU');  // → true
isMCPSupportedWBCountryCode('EUU');  // → false (aggregate)
isMCPSupportedWBCountryCode('UK');   // → false (use 'GB')
isMCPSupportedWBCountryCode('');     // → false
```
- Defined in utils/world-bank-data.ts:219