18 tools with consistent verb_noun naming (send_sms, get_contacts, read_sms). All tools have descriptions (10 - 200 chars, within baseline). Input schemas present with Zod validation and parameter descriptions. However, output schemas are NOT documented, responses are returned as generic text blobs via the text() helper without structured field definitions. No error recovery guidance (e.g., 'If SMS fails, check network'). Missing tool annotations (readOnlyHint, destructiveHint, idempotentHint). Parameter descriptions are adequate but lack format constraints (e.g., phone number regex, duration ranges). No pagination support for list-returning tools (read_sms, get_contacts, get_call_log). Security concern: no permission gates or audit logging visible.

• Add structured output schemas to all tools. Document return fields (e.g., read_sms returns [{id, from, body, timestamp}], get_battery returns {level: number, status: string, temperature: number}). Use JSON Schema in tool definitions.
• Implement pagination for read_sms, get_contacts, get_call_log. Add offset/limit parameters and return {items: [...], total_count: N, has_more: boolean}.
• Add tool annotations via MCP SDK: mark send_sms, make_call, take_photo, record_audio, set_clipboard, set_volume, flashlight, vibrate, send_notification with destructiveHint=true. Mark all get_* tools with readOnlyHint=true.
• Enhance error messages with recovery guidance. E.g., 'SMS send failed: network unavailable. Check WiFi/cellular connection and retry.' or 'Location timeout: GPS disabled. Enable location services and try again with provider=network.'
• Add parameter constraints: send_sms.to as regex pattern (E.164 format); vibrate.duration_ms as min=1, max=5000; record_audio.duration_s as min=1, max=300; set_volume.volume as min=0, max=15; get_location.provider as enum [gps, network, passive].