fix(core): prevent asyncpg engine-dispose crash on Postgres backend (#902)

Signed-off-by: phernandez <paul@basicmachines.co>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/basic_memory/cli/app.py

@@ -57,6 +57,14 @@ def app_callback(
     container = CliContainer.create()
     set_container(container)
 
+    # Trigger: Postgres backend resolved at CLI startup, before any asyncio.run().
+    # Why: uvloop must own the event-loop policy before the loop is created so the
+    # asyncpg engine-dispose race (#831/#877) cannot fire. No-op for SQLite.
+    # Outcome: subsequent asyncio.run() calls in CLI commands use uvloop on Postgres.
+    from basic_memory.db import maybe_install_uvloop
+
+    maybe_install_uvloop(container.config)
+
     # Trigger: first-run init confirmation before command output.
     # Why: informational "initialized" message belongs above command results, not in the upsell panel.
     # Outcome: one-time plain line printed before the subcommand runs.

src/basic_memory/cli/commands/mcp.py

@@ -98,6 +98,18 @@ def mcp(
     if transport == "stdio":
         threading.Thread(target=_run_background_auto_update, daemon=True).start()
 
+    # Trigger: MCP server startup on the Postgres backend, before the transport
+    # creates its event loop.
+    # Why: the watcher/lifespan path runs startup migrations + engine.dispose() on
+    # asyncpg, which races stdlib asyncio teardown and crashes the container loop
+    # (#831/#877). uvloop's C scheduler structurally avoids that race and must own
+    # the loop policy before the loop is created. No-op for SQLite.
+    # Outcome: `basic-memory mcp` on Postgres runs on uvloop. (The CLI callback also
+    # installs it; this keeps the server startup seam explicit and self-contained.)
+    from basic_memory.db import maybe_install_uvloop
+
+    maybe_install_uvloop(ConfigManager().config)
+
     # Run the MCP server (blocks)
     # Lifespan handles: initialization, migrations, file sync, cleanup
     logger.info(f"Starting MCP server with {transport.upper()} transport")