Strong tool design with clear naming (verb_noun pattern), comprehensive schemas, and detailed descriptions. All 12 tools have explicit input schemas with proper JSON Schema structure. Descriptions average ~180 chars, well within the 10-1024 baseline. Key strengths: draft/confirm pattern prevents accidental sends (pattern:confirmation-request); idempotent confirm_send; multi-message-type support. Gaps: no tool annotations (readOnlyHint/destructiveHint/idempotentHint); output schemas not formally documented in code; some parameter descriptions could be more prescriptive about constraints.

• Add tool annotations to all tool definitions: readOnlyHint=true for get_status, list_sessions, health_check, resolve_recipient, list_groups, list_recent; destructiveHint=true for confirm_send, schedule_send; idempotentHint=true for confirm_send (already documented as idempotent in description).
• Document output schemas as JSON Schema in the ToolDef interface. E.g., draft_message returns { draftId: string, preview: string, expiresInSec: number }; confirm_send returns { messageId: string, timestamp: string, status: string }.
• Add explicit constraints to draft_message: path must be absolute, max 4096 chars, no traversal (..); latitude ∈ [-90, 90]; longitude ∈ [-180, 180]; text max 4096 chars.
• Add pagination to list_scheduled and list_recent: limit (1-100, default 20), offset (default 0). Document max result size and truncation behavior.
• Enhance error descriptions with recovery guidance. E.g., resolve_recipient: 'If no match found, returns { candidates: [] }. Try a different query or use phone number format.'; confirm_send: 'If session not connected, returns error with status. Call health_check first to verify.'

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry