Three tools with complete input schemas and detailed descriptions. Naming follows verb_noun pattern (calculate_chart, get_transits, compare_charts). Descriptions are comprehensive (200-400 chars) and explain WHAT, WHEN, and RETURN. However, output schemas are not formally documented, responses are JSON strings without declared field structures. Parameters lack enums for constrained values (e.g., birth_month should be 1-12 enum, not free integer). No error handling guidance or recovery paths. No tool annotations (readOnlyHint, idempotentHint). Composition is sound: each tool has one responsibility, and outputs contain IDs for chaining.

• Add formal output schema documentation. Define the structure of returned JSON: e.g., 'Returns object with fields: type (string), profile (string), authority (string), channels (array of {id, name, definition}), gates (array of {number, line}), variables (object with 4 arrows), etc.' Use JSON Schema or TypedDict in docstrings.
• Convert free-form integer parameters to enums: birth_month: enum [1-12], birth_day: enum [1-31], birth_hour: enum [0-23], birth_minute: enum [0-59]. Add validation in tool implementation to reject out-of-range values with actionable error messages.
• Add error handling with recovery guidance. E.g., 'If birth_place is not recognized, try providing utc_offset explicitly (e.g., 3.0 for UTC+3). Common cities: Moscow, New York, London, Tokyo.'
• Annotate tools with readOnlyHint=true in tool registration (FastMCP supports this via @mcp.tool(readOnly=True)). This signals to agents that calls are safe to retry without side effects.
• For compare_charts, consider adding optional person1_name and person2_name defaults ('Person 1', 'Person 2') and document that birth_place is optional if utc_offset is provided. Reduce cognitive load for simple queries.