Sensei MCP has 5 tools with verb-noun naming (get_, record_, validate_, list_) and descriptions present. However, critical gaps undermine quality: (1) Input schemas are inferred from function signatures but NOT explicitly visible in JSON Schema format in the code, cannot verify type definitions, constraints, or enums. (2) Parameter descriptions exist in docstrings but are generic ('Session identifier', 'Absolute path') without format/constraint guidance. (3) Output schemas are completely undocumented, tools return markdown strings or confirmation messages with no structured schema declaration. (4) No error handling guidance; tools silently fail or return generic strings. (5) session_id and project_root parameters appear in every tool, suggesting stateful session management (deprecated pattern). Per-tool average: 52.

• Add explicit JSON Schema definitions to all tools. Use @mcp.tool() decorator with input_schema parameter or equivalent fastmcp mechanism to declare types, enums, min/max, and patterns for every parameter. Example: focus_areas should be array of strings with enum values like ['naming', 'error-handling', 'security'].
• Document output schemas for all tools. Define structured return types (e.g. {decision_id: string, timestamp: string, category: string} for record_decision) instead of free-form markdown. Enable LLM chaining and reduce parsing errors.
• Enhance parameter descriptions with format and constraint guidance. Replace 'Session identifier' with 'Session identifier (alphanumeric, 1-64 chars, lowercase). Defaults to "default" if omitted.' Replace 'Absolute path' with 'Absolute path to project root (must exist and be readable; used to load local rules and sessions).'
• Add error handling guidance to tool descriptions. Document what errors can occur, whether they are retryable, and what the LLM should do next. Example: 'If session not found, call list_sessions() to see available sessions, or create a new one by calling record_decision() with a new session_id.'
• Refactor session management to be stateless. Pass session context (decisions, constraints, patterns) as tool parameters or load from a configuration file at startup, rather than maintaining server-side state keyed by session_id. Align with current MCP spec (2026-07-28) which removed Mcp-Session-Id.