diff --git a/examples/acp-agent/tests/snapshots/web-fetch/tool-schemas.expected.json b/examples/acp-agent/tests/snapshots/web-fetch/tool-schemas.expected.json
index 1ee86b38ba..70940f8907 100644
--- a/examples/acp-agent/tests/snapshots/web-fetch/tool-schemas.expected.json
+++ b/examples/acp-agent/tests/snapshots/web-fetch/tool-schemas.expected.json
@@ -288,7 +288,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",