Three tools with complete input schemas and descriptions. Naming follows verb_noun pattern (navigate, list_metrics, get_metric_data). Descriptions are detailed (194 - 280 chars) and explain the hierarchy model well. However, output schemas are entirely undocumented, LLMs cannot plan downstream calls or extract fields. Parameter descriptions lack format constraints (e.g., no enum for theme values, no min/max for page_size). No error handling guidance. Missing tool annotations (readOnlyHint). The navigate tool's optional parameters lack clear dependency documentation.

• Document output schemas for all three tools. For navigate/list_metrics, specify: {results: [{name: string, link: string}]}. For get_metric_data, specify: {count: number, next: string|null, previous: string|null, results: [{date: string, metric_value: number, year: number, month: number, epiweek: number, sex: string, age: string, stratum: string, geography_code: string}]}.
• Add enum constraints to theme, sub_theme, topic, geography_type parameters. E.g., theme: {type: 'string', enum: ['infectious_disease', 'immunisation', 'climate_and_environment', 'medicines']}. This prevents hallucinated values and self-documents valid options.
• Add min/max bounds to numeric parameters. E.g., page_size: {type: 'number', minimum: 1, maximum: 365}, page: {type: 'number', minimum: 1}. Include these in descriptions: 'Observations per page (1 - 365, default 5).'
• Document parameter dependencies explicitly in schema and descriptions. For navigate(), mark sub_theme, topic, geography_type, geography as conditionally required based on prior levels. E.g., 'sub_theme requires theme to be set.'
• Add error handling guidance to descriptions. E.g., 'If theme is invalid, returns 404 with available themes. Call navigate() with no args to discover valid themes.' This guides LLM recovery.