Server provides 6 well-structured tools with complete JSON Schema input definitions and descriptions in Japanese. Tool names follow verb_noun convention (createEntries, setActiveEntry, etc.). All tools have documented input schemas with proper type constraints. However, the server has several notable gaps: (1) Output schemas are NOT documented, LLMs have no formal specification of return types, (2) Parameter descriptions are minimal and assume Japanese-literate LLMs, (3) No error recovery guidance is provided in descriptions despite UserError handling in code, (4) No tool annotations (readOnlyHint, destructiveHint, idempotentHint) declared despite clear semantic intent, (5) Composition could be stronger, updateEntry requires at least one of 'note' or 'status', but this constraint is expressed via Zod refine, not accessible to the MCP schema consumer. The definitions are functional but lack LLM-optimized clarity for discovery and error recovery.

• Add formal output schemas to each tool definition. Example for createEntries: { type: 'object', properties: { entryIds: { type: 'array', items: { type: 'string' }, description: 'Array of created entry IDs' } }, required: ['entryIds'] }
• Declare tool annotations in buildEntryTools(). Add destructiveHint to deleteEntries and updateEntry; add readOnlyHint to getActiveEntry and listEntries. Example: { ...tool, destructiveHint: true }
• Fix updateEntry schema to express the 'at least one of note/status' constraint in JSON Schema (using oneOf or allOf). Do not rely on Zod refine, which the MCP consumer cannot inspect.
• Enhance error messages with recovery guidance. Example: catch block for 'entry not found' → 'Entry not found. Call listEntries() to see available entries or createEntries() to add new ones.'
• Translate all parameter descriptions to English or provide English as a fallback. Japanese descriptions limit LLM comprehension for non-Japanese models. Use a translation layer or dual-language docs.
• Add pagination to listEntries: introduce optional 'limit' (default 20, max 100) and 'offset' (default 0) parameters, and return {entries: [...], total: N, hasMore: bool}.
• Document when to use each tool. Example for setActiveEntry: 'Use to focus on a specific entry for detailed work. Once set, getActiveEntry() returns the current focus.'
• Consider adding a deleteEntry (singular) tool for single-entry deletion, to match the create/update/delete trio pattern more idiomatically.