Four well-named tools with clear, actionable descriptions (avg 156 chars). All tools have complete input schemas with proper Zod validation, type constraints, and parameter descriptions. Naming follows verb_noun pattern (search_, get_, latest_, convert_). Error handling via guarded() wrapper surfaces API errors to LLM for self-correction. Output schemas are JSON-serialized but not formally documented. No tool annotations (readOnlyHint, etc.). Parameter constraints are well-specified (regex patterns, min/max, enums via length validation). Missing: explicit output schema documentation, tool annotations for read-only operations.

• Add explicit output schema documentation to each tool. Example for search_series: 'Returns array of {name: string, label: string, description: string}'. For get_observations: '{seriesDetail: {[key]: {label, description}}, observations: [{date: YYYY-MM-DD, values: {[series]: value}}]}'.
• Add readOnlyHint: true to all four tool schemas to signal to clients that these are safe, non-destructive operations.
• Document mutually exclusive parameters in get_observations: 'Either provide start_date+end_date for a range, OR recent for N most recent observations. Do not combine.'
• For convert_currency, add a note in the description: 'Supported currencies are those in latest_fx_rates. Call that tool first to see available pairs if unsure.'
• Consider adding a list_supported_currencies tool or returning available currencies in latest_fx_rates response to enable validation before convert_currency calls.