diff --git a/crates/rmcp/src/transport/common/mcp_headers.rs b/crates/rmcp/src/transport/common/mcp_headers.rs
index fe75b34b9..294abb7bc 100644
--- a/crates/rmcp/src/transport/common/mcp_headers.rs
+++ b/crates/rmcp/src/transport/common/mcp_headers.rs
@@ -211,8 +211,8 @@ fn has_off_chain_annotation(schema: &JsonObject, on_chain: bool) -> bool {
         "$defs" | "definitions" | "dependentSchemas" | "patternProperties" => {
             schema_map_has_off_chain_annotation(value, false)
         }
-        // Instance data, not subschemas.
-        "default" | "const" | "enum" | "examples" => false,
+        // These contain instance data or property names, not subschemas.
+        "default" | "const" | "enum" | "examples" | "dependentRequired" => false,
         _ => subschema_has_off_chain_annotation(value, false),
     })
 }
@@ -735,6 +735,35 @@ mod tests {
             assert!(validate_param_header_annotations(&schema).is_err());
         }
 
+        #[test]
+        fn accepts_property_name_in_dependent_required() {
+            let schema = json!({
+                "type": "object",
+                "properties": {
+                    "x-mcp-header": { "type": "string" },
+                    "tenant": { "type": "string", "x-mcp-header": "Tenant" }
+                },
+                "dependentRequired": { "x-mcp-header": ["tenant"] }
+            });
+            assert_eq!(
+                validate_param_header_annotations(schema.as_object().unwrap()),
+                Ok(())
+            );
+        }
+
+        #[test]
+        fn rejects_header_annotation_inside_dependent_schema() {
+            let schema = json!({
+                "type": "object",
+                "dependentSchemas": {
+                    "tenant": {
+                        "properties": { "region": { "type": "string", "x-mcp-header": "Region" } }
+                    }
+                }
+            });
+            assert!(validate_param_header_annotations(schema.as_object().unwrap()).is_err());
+        }
+
         #[test]
         fn ignores_annotation_key_in_default_value() {
             let schema = schema_with(json!({
diff --git a/crates/rmcp/src/transport/streamable_http_client.rs b/crates/rmcp/src/transport/streamable_http_client.rs
index db44ab3fb..8b964be94 100644
--- a/crates/rmcp/src/transport/streamable_http_client.rs
+++ b/crates/rmcp/src/transport/streamable_http_client.rs
@@ -2603,6 +2603,46 @@ mod tests {
         );
     }
 
+    #[test]
+    fn cache_tools_keeps_property_names_in_dependent_required() {
+        let valid = tool(
+            "valid",
+            json!({
+                "type": "object",
+                "properties": {
+                    "x-mcp-header": { "type": "string" },
+                    "tenant": { "type": "string", "x-mcp-header": "Tenant" }
+                },
+                "dependentRequired": { "x-mcp-header": ["tenant"] }
+            }),
+        );
+        let mut message = ServerJsonRpcMessage::response(
+            ServerResult::ListToolsResult(ListToolsResult::with_all_items(vec![valid])),
+            NumberOrString::Number(1),
+        );
+        let mut cache = HashMap::new();
+
+        cache_tools_from_response(&mut cache, &mut message, &ProtocolVersion::V_2026_07_28);
+
+        let ServerJsonRpcMessage::Response(response) = message else {
+            panic!("expected tools/list response");
+        };
+        let ServerResult::ListToolsResult(result) = response.result else {
+            panic!("expected tools/list result");
+        };
+        assert_eq!(
+            (
+                result
+                    .tools
+                    .iter()
+                    .map(|tool| tool.name.as_ref())
+                    .collect::<Vec<_>>(),
+                cache.keys().map(String::as_str).collect::<Vec<_>>(),
+            ),
+            (vec!["valid"], vec!["valid"])
+        );
+    }
+
     #[test]
     fn cache_tools_keeps_nested_annotations_and_drops_array_annotations() {
         let nested = tool(