diff --git a/src/core/mcp/include/sourcemeta/core/mcp.h b/src/core/mcp/include/sourcemeta/core/mcp.h
index eb4b75dd68..8d4c87c9aa 100644
--- a/src/core/mcp/include/sourcemeta/core/mcp.h
+++ b/src/core/mcp/include/sourcemeta/core/mcp.h
@@ -321,13 +321,12 @@ auto mcp_make_tool_error(const sourcemeta::core::JSON &identifier,
 /// #include <cassert>
 ///
 /// const auto identifier{sourcemeta::core::JSON{3}};
-/// const auto envelope{sourcemeta::core::mcp_make_error_resource_not_found(
-///     identifier, "file:///missing")};
+/// const auto envelope{
+///     sourcemeta::core::mcp_make_error_resource_not_found(identifier)};
 /// assert(envelope.at("error").at("code").to_integer() == -32002);
 /// ```
 SOURCEMETA_CORE_MCP_EXPORT
-auto mcp_make_error_resource_not_found(const sourcemeta::core::JSON &identifier,
-                                       const JSON::StringView uri)
+auto mcp_make_error_resource_not_found(const sourcemeta::core::JSON &identifier)
     -> sourcemeta::core::JSON;
 
 /// @ingroup mcp
diff --git a/src/core/mcp/mcp.cc b/src/core/mcp/mcp.cc
index 1585ae3c74..969a9587a3 100644
--- a/src/core/mcp/mcp.cc
+++ b/src/core/mcp/mcp.cc
@@ -178,12 +178,10 @@ auto mcp_make_tool_error(const sourcemeta::core::JSON &identifier,
                                                 std::move(envelope_result));
 }
 
-auto mcp_make_error_resource_not_found(const sourcemeta::core::JSON &identifier,
-                                       const JSON::StringView uri)
+auto mcp_make_error_resource_not_found(const sourcemeta::core::JSON &identifier)
     -> sourcemeta::core::JSON {
   return sourcemeta::core::jsonrpc_make_error(
-      &identifier, MCP_CODE_RESOURCE_NOT_FOUND, "Resource not found",
-      sourcemeta::core::JSON{uri});
+      &identifier, MCP_CODE_RESOURCE_NOT_FOUND, "Resource not found");
 }
 
 auto mcp_make_resource(const JSON::StringView uri, const JSON::StringView name,
diff --git a/test/mcp/mcp_test.cc b/test/mcp/mcp_test.cc
index 87e58b01d8..60aa86a9f4 100644
--- a/test/mcp/mcp_test.cc
+++ b/test/mcp/mcp_test.cc
@@ -564,15 +564,14 @@ TEST(MCP, tool_error_with_null_id) {
 
 TEST(MCP, error_resource_not_found_with_integer_id) {
   const auto identifier{sourcemeta::core::JSON{3}};
-  const auto envelope{sourcemeta::core::mcp_make_error_resource_not_found(
-      identifier, "file:///missing")};
+  const auto envelope{
+      sourcemeta::core::mcp_make_error_resource_not_found(identifier)};
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "jsonrpc": "2.0",
     "id": 3,
     "error": {
       "code": -32002,
-      "message": "Resource not found",
-      "data": "file:///missing"
+      "message": "Resource not found"
     }
   })JSON")};
   EXPECT_EQ(envelope, expected);
@@ -580,15 +579,14 @@ TEST(MCP, error_resource_not_found_with_integer_id) {
 
 TEST(MCP, error_resource_not_found_with_string_id) {
   const auto identifier{sourcemeta::core::JSON{"req-7"}};
-  const auto envelope{sourcemeta::core::mcp_make_error_resource_not_found(
-      identifier, "file:///missing")};
+  const auto envelope{
+      sourcemeta::core::mcp_make_error_resource_not_found(identifier)};
   const auto expected{sourcemeta::core::parse_json(R"JSON({
     "jsonrpc": "2.0",
     "id": "req-7",
     "error": {
       "code": -32002,
-      "message": "Resource not found",
-      "data": "file:///missing"
+      "message": "Resource not found"
     }
   })JSON")};
   EXPECT_EQ(envelope, expected);