Server has 30 tools with explicit schemas and descriptions. Naming follows verb_noun convention (search_, get_, list_, etc.). Most tools have 4-6 parameters with type definitions. However, descriptions are often generic (10-50 chars), parameter descriptions lack actionable constraints, and output schemas are not documented in the visible code. Error handling is minimal, no recovery guidance or categorization. Session management tools mix READ and WRITE operations without clear state-change documentation. Cache management tools (delete_cache, prune_cache) lack confirmation patterns despite destructive risk.

• Add output schema documentation to every tool. Specify returned fields, types, and which fields are safe to pass to downstream tools. Example: 'Returns {results: [{id, title, source, url}], total_count, next_page_token}'.
• Enhance parameter descriptions with constraints and examples. Replace 'Search query' with 'Free-text search query (1-500 chars, supports AND/OR operators). Example: "Meiji literature AND poetry"'.
• Implement confirmation pattern for destructive tools. Add a 'dry_run' parameter to delete_cache and prune_cache, or require explicit confirmation via a separate confirm_deletion tool.
• Document state changes in WRITE tool descriptions. Clarify: 'Creates a new session and stores it persistently. Subsequent calls with the same title will return the existing session (idempotent).' or 'Appends notes to session (non-idempotent; each call adds a new entry)'.
• Add error handling guidance. Return structured errors with recovery hints: '{error: "Source not found", code: "SOURCE_UNKNOWN", hint: "Available sources: ndl_catalog, cinii_books, jstage_articles. Did you mean cinii_books?"}'