Habitica MCP has clear, action-oriented tool names (get_stats, list_tasks, add_task, etc.) and reasonable descriptions (avg ~120 chars). All 12 tools have input schemas with type definitions and parameter descriptions. However, schemas lack enums for constrained inputs (task_type, priority, direction), output schemas are not documented, and error handling is minimal. The _safe() wrapper converts exceptions to strings but provides no recovery guidance. Parameter descriptions are present but sparse (avg ~50 chars) and lack format/range constraints. No tool annotations (readOnlyHint/destructiveHint) despite clear risk levels. Descriptions are adequate but not LLM-optimized per pattern:tool-description baseline (target 50-200 chars).

• Add enum constraints to task_type (habit|daily|todo|reward), priority (0.1|1|1.5|2), direction (up|down), and frequency parameters. Use JSON Schema enum field.
• Document output schemas for all tools. E.g., get_stats returns {lvl, class, hp, mp, exp, gp, toNextLevel}; list_tasks returns [{id, type, text, completed?, due?, priority?, tags?, checklist?}].
• Enhance error messages with recovery guidance. E.g., 'Task not found (ID: abc123). Try list_tasks() to find valid task IDs.' Use structured error objects with code, message, and recovery_hint fields.
• Add tool annotations via FastMCP's @mcp.tool() decorator or response metadata. Mark read-only tools with readOnlyHint=true, destructive tools with destructiveHint=true, and idempotent tools with idempotentHint=true.
• Expand parameter descriptions to 50-150 chars with explicit constraints. E.g., 'Priority level (0.1=trivial, 1=easy, 1.5=medium, 2=hard). Affects reward value and difficulty scaling.' Include format hints for dates: 'ISO 8601 date (YYYY-MM-DD), e.g., 2025-12-31'.