Single tool with basic definition. Tool name 'search_user' follows verb_noun convention (+). Description is present but generic (58 chars, below 194-char baseline). Input schema visible with type and description for 'username' parameter (+). However, output is unstructured JSON string rather than typed schema, and no error handling guidance. Missing parameter constraints (min/max length), no pagination support despite potentially returning many results, and no documentation of what 'multiple sites' means or how many results to expect. No tool annotations (readOnlyHint, etc.). Lacks recovery guidance for common failures (e.g., 'No results found' is bare, not actionable).

• Define output schema as structured object: {results: [{site: string, url_main: string, url_user: string}], total_found: number, search_time_ms: number}. Return typed JSON, not string.
• Add parameter constraints to 'username': min 1 char, max 50 chars, alphanumeric + underscore/dash. Document in description: 'Username to search (1-50 chars, alphanumeric + _ -).'
• Document result limits and pagination: 'Returns up to 50 matching sites. If more exist, implement pagination via offset/limit parameters or next_cursor.'
• Enhance error messages with recovery guidance: 'No results found for "username". Try: (1) Check spelling, (2) Search with partial name, (3) Try different username variants.'
• Expand tool description to 100-150 chars: 'Search for a username across 500+ social media and web platforms using Sherlock. Returns sites where the username exists with direct profile URLs. Useful for OSINT, account verification, or finding alternate profiles.'