Memory MCP Server demonstrates strong schema discipline, comprehensive parameter documentation, and thoughtful tool design centered around a graph-backed memory abstraction. All 13 tools are explicitly registered with input/output schemas (visible in src/lib/tool-contracts.ts), descriptions range 75 - 180 chars (within baseline 34 - 392), and parameters consistently include type, description, and constraints. Tool annotations (readOnlyHint, idempotentHint, destructiveHint) are correctly applied per operation semantics. Batch operations (store_memories, delete_memories) follow composition best practices. However, several gaps prevent an A grade: (1) error handling is declared at the schema level but lacks actionable recovery guidance in descriptions (e.g., 'Returns E_NOT_FOUND if missing' does not explain what the agent should do next); (2) output schema documentation is complete but terse, no guidance on which fields enable chaining (e.g., which fields from recall() should be passed to downstream tools); (3) some parameter constraints are encoded in descriptions but lack formal JSON Schema constraints (e.g., 'importance_min: 0-10' is stated in text, not as minValue/maxValue); (4) secret injection and audit trail patterns are not addressed in visible code.

• Enhance error descriptions with recovery guidance. E.g., 'get_memory: Retrieve memory by SHA-256 hash. Returns error if not found, call search_memories() first if you only know partial content or tags.' (pattern: recovery-guide)
• Formalize numeric constraints in JSON Schema. Add minValue: 0, maxValue: 10 to importance parameters; minValue: 1, maxValue: 100 to limit parameters. Update descriptions to reference these schema constraints.
• Document output chaining explicitly. E.g., recall(): 'Returns array of memories (each with hash field for use in update_memory/delete_memory) and edges (each with from_hash, to_hash, relation_type for use in delete_relationship). Supports pagination via cursor.'
• Add confirmation-request support for destructive ops. E.g., delete_memories() should accept an optional 'confirmed: boolean' parameter with description 'Must be true to execute; omit to get a preview showing what would be deleted.'
• Implement and document audit trail. Log tool invocations with timestamp, caller ID, parameters, and result to a structured audit log (file or database). Document this in README with schema example.
• Introduce permission-gate pattern if multi-user scenarios are expected. E.g., 'Each tool requires the calling user to have read:memory or write:memory scope. Calls from agents without proper scope are rejected with a clear permission error.'
• Expand memory_stats description to indicate what kind of analysis it enables. E.g., 'Get aggregate statistics: total memory count, timestamp range, average importance. Use before retrieve_context to estimate how much coverage the KB provides.'

Inferred effective spec: 2025-06-18+.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry