Add MemorySync persistent memory cursor rule

rules/memorysync-persistent-memory.mdc

@@ -0,0 +1,44 @@
+---
+description: Scoped persistent memory guidelines for Cursor AI to capture and recall architecture decisions, API conventions, and project constraints across sessions via MemorySync MCP.
+globs: ["**/*"]
+alwaysApply: false
+---
+# MemorySync Persistent Memory for Cursor
+
+This rule guides Cursor AI in maintaining persistent, scoped project memory across conversation restarts using the MemorySync Model Context Protocol (MCP) server.
+
+## Connection Setup
+Ensure the MemorySync MCP server is configured in `.cursor/mcp.json` or Cursor Settings > Features > MCP:
+
+```json
+{
+  "mcpServers": {
+    "memorysync": {
+      "url": "https://mcp.memorysync.io/mcp"
+    },
+    "memorysync-docs": {
+      "url": "https://docs.memorysync.io/mcp"
+    }
+  }
+}
+```
+
+## When to Save Memories
+Automatically invoke memory storage when the user or project establishes durable decisions:
+- **Architecture Decisions:** Choice of libraries, state management patterns, routing conventions.
+- **Project Conventions:** Date formatting (e.g., strict UTC ISO-8601), naming styles, error handling structures.
+- **Bug Fixes & Gotchas:** Non-obvious edge cases resolved, pinned package workarounds, deprecated API replacements.
+- **Environment & Secrets:** Key configuration variables needed (never store plaintext secrets or private tokens).
+
+## When to Recall Memories
+At the start of new tasks, feature implementations, or refactoring:
+- Query MemorySync for existing decisions scoped to the current project or workspace (`project_id`).
+- Respect recalled decisions rather than guessing or re-implementing contrasting patterns.
+- Cite the memory record ID when applying a recalled rule (e.g., `Applied architecture constraint from memory #mem_...`).
+
+## Documentation Search
+When encountering unfamiliar SDK APIs or framework features:
+- Use `memorysync-docs` to search live, verified documentation before generating speculative implementations.
+
+## Reference
+- Official Cursor Guide: [docs.memorysync.io/guides/cursor](https://docs.memorysync.io/guides/cursor)