Add iai-mcp-session-init plugin for automatic memory loading in OpenCode

deploy/opencode/iai-mcp-session-init.js

@@ -0,0 +1,40 @@
+/**
+ * iai-mcp session-init plugin for OpenCode.
+ *
+ * Sets the system prompt via chat.message hook's UserMessage.system field.
+ * This reaches the main agent and triggers memory_session_context on every session.
+ */
+
+export const IaiMcpSessionInit = async ({
+  client,
+  project,
+  directory,
+  worktree,
+  experimental_workspace,
+  serverUrl,
+  $,
+}) => {
+  const injectedSessions = new Set();
+
+  return {
+    event: async ({ event }) => {
+      if (event.type !== "session.updated") return;
+      const sid = event.properties?.info?.id;
+      if (!sid || injectedSessions.has(sid)) return;
+      injectedSessions.add(sid);
+    },
+
+    "chat.message": async (input, output) => {
+      const sid = input.sessionID;
+      if (!sid || !injectedSessions.has(sid)) return;
+      if (injectedSessions.has(`done-${sid}`)) return;
+
+      if (output.message) {
+        output.message.system =
+          "MANDATORY: Call `memory_session_context` (no arguments) BEFORE answering any user query.";
+      }
+
+      injectedSessions.add(`done-${sid}`);
+    },
+  };
+};