Errorbook demonstrates solid tool design with consistent naming (verb_noun pattern), comprehensive parameter descriptions, and structured error handling. All 12 tools have descriptions (avg 156 chars, within baseline 194). Input schemas are present with type definitions and enums for constrained values (e.g., outcome, status, priority_delta). However, output schemas are not explicitly documented in the visible code, responses are inferred from error handling patterns. Idempotency keys and version-based optimistic locking show production maturity. Chinese descriptions are clear but reduce LLM compatibility for English-only agents. Error responses include retryable classification and actionable guidance (e.g., 'DATABASE_BUSY' with retry hint). Minor gaps: no tool annotations (readOnlyHint/destructiveHint), output structure not formally declared, and some parameter relationships (e.g., mode-dependent fields in ReviewSheetRequest) lack explicit documentation.

• Add explicit output schema documentation for all 12 tools. Define response structure (e.g., {ok: bool, data?: {...}, error?: {code, message, retryable, details}}) in tool docstrings or a separate schema file.
• Implement tool annotations: mark get_* and search_* with readOnlyHint=true; mark delete_export, set_problem_status, update_problem with destructiveHint=true; mark all write operations with idempotentHint=true (since idempotency_key is supported).
• Provide English translations or bilingual descriptions. Keep Chinese for domain clarity but add English equivalents so English-only agents can select tools correctly.
• Document parameter dependencies explicitly: 'ReviewSheetRequest.mode: If mode=scheduled, horizon_days and max_questions apply; if mode=custom, numbers must be provided; if mode=subjects_tags, subjects and/or tags must be provided.'
• Clarify pagination: 'Returns up to limit results. Response includes total_count and has_more flag. Use offset to fetch subsequent pages.' Add these fields to list_exports and search_problems responses.

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

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