(sling-org-apache-sling-mcp-server) 23/27: fix(mcp-server): ignore unknown properties during deserialisation

[ro...@apache.org]

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rombert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/sling-org-apache-sling-mcp-server.git

commit 8e6ffef6b6ab363ece13b125ca347349bcbe60a1
Author: Robert Munteanu <ro...@apache.org>
AuthorDate: Tue Jan 13 13:30:01 2026 +0100

    fix(mcp-server): ignore unknown properties during deserialisation
    
    Workaround for upstream issue https://github.com/modelcontextprotocol/java-sdk/issues/724 . This
    appears with MCP clients implementing the 2025-11-25 version of the spec which supports more
    properties for the 'elicitation' object.
    
    For now, we ignore unknown properties since there is no release of the MCP Java SDK that contains
    the fix.
---
 .../org/apache/sling/mcp/server/impl/McpJsonMapperProvider.java    | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/apache/sling/mcp/server/impl/McpJsonMapperProvider.java b/src/main/java/org/apache/sling/mcp/server/impl/McpJsonMapperProvider.java
index 74bece1..5df93df 100644
--- a/src/main/java/org/apache/sling/mcp/server/impl/McpJsonMapperProvider.java
+++ b/src/main/java/org/apache/sling/mcp/server/impl/McpJsonMapperProvider.java
@@ -27,6 +27,8 @@ import org.osgi.service.component.annotations.Activate;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Deactivate;
 
+import static com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES;
+
 @Component
 public class McpJsonMapperProvider {
 
@@ -34,7 +36,10 @@ public class McpJsonMapperProvider {
 
     @Activate
     public void activate(BundleContext bundleContext) {
-        McpJsonMapper jsonMapper = new JacksonMcpJsonMapper(new ObjectMapper());
+        ObjectMapper objectMapper = new ObjectMapper();
+        // work around https://github.com/modelcontextprotocol/java-sdk/issues/724
+        objectMapper.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
+        McpJsonMapper jsonMapper = new JacksonMcpJsonMapper(objectMapper);
         serviceRegistration = bundleContext.registerService(McpJsonMapper.class, jsonMapper, null);
     }