diff --git a/packages/agentctx/src/mcp/tools.ts b/packages/agentctx/src/mcp/tools.ts
index 5a566f6..0fdef2c 100644
--- a/packages/agentctx/src/mcp/tools.ts
+++ b/packages/agentctx/src/mcp/tools.ts
@@ -357,7 +357,9 @@ export function toolDefinitions(): ToolDefinition[] {
           ids: {
             type: "array",
             items: { type: "string" },
-            description: `Record ids from ctx_search/ctx_related (max ${GET_IDS_MAX})`,
+            minItems: 1,
+            maxItems: GET_IDS_MAX,
+            description: `Record ids from ctx_search/ctx_related (at least 1, max ${GET_IDS_MAX})`,
           },
         },
         required: ["ids"],