MemPalace is a local-first, persistent memory system for AI agents. It stores and retrieves structured 'drawers' (memory chunks) organized into wings, rooms, and closets, with hybrid vector+BM25 search, a temporal knowledge graph, and agent coordination via a logstream. The system provides a CLI, an MCP server (both full and lightweight), and shell hooks for integration with Claude Code, Cursor, Codex, Antigravity, and DeepSeek Harness. It supports multiple storage backends (ChromaDB, SQLite exact, pgvector, Qdrant, Milvus, and a Rust native backend) and offers privacy-first operation with no mandatory API keys or internet connectivity. Architecturally, MemPalace is a modular Python package with optional Rust acceleration (PyO3). The core is split into several packages: `mempalace.cli` (fragment-exec-based CLI), `mempalace.mcp_server` (MCP tool server), `mempalace.palace` (palace operations and locks), `mempalace.searcher` (hybrid ranking and filters), and `mempalace.backends` (pluggable storage). The knowledge graph is SQLite-backed with temporal validity windows. A write-ahead log provides an audit trail. The system uses a hybrid logical clock (HLC) for causal ordering and a source adapter system for pluggable ingest. Although primarily an application, the project includes extensive benchmarking and model evaluation suites, giving it a mild hybrid character.