store: Multi-graph support: named, segregated memory namespaces for cognitive memory

graph/decisions/multi-graph-support-named-segregated-memory-namespaces-for-c-b1ba1b.md

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+---
+id: b1ba1b27-d2bf-44f9-a1f5-0ace2017dc18
+type: decision
+title: "Multi-graph support: named, segregated memory namespaces for cognitive memory"
+tags: ["[\"cognitive-memory\"", "multi-graph", "architecture", "mcp", "\"v3.1.0\"]"]
+importance: 0.8
+confidence: 0.8
+created: "2026-02-28T20:56:05.164875+00:00"
+updated: "2026-02-28T20:56:05.164875+00:00"
+---
+
+# Multi-graph Support for Cognitive Memory (v3.1.0)
+
+Implemented multi-graph support for cognitive memory (Gitea issue #1).
+
+## Architecture
+Centralized storage with named graphs. Default graph unchanged; named graphs live as siblings to the default.
+
+## Changes Made
+- **common.py**: Added `resolve_graph_path()` and `list_graphs()` helpers
+- **mcp_server.py**: Added client cache dict with `get_client(graph)` routing, added `"graph"` param on all 18 tools, added new `memory_graphs` tool (19th tool total)
+- **cli.py**: Added `--graph` flag and `graphs` subcommand
+
+## Backward Compatibility
+All existing calls without `graph` param route to default graph. Auto-init on first use via `_ensure_dirs()`.
+
+## Version
+Bumped to 3.1.0.