diff --git a/mcp-bom/pom.xml b/mcp-bom/pom.xml
index b06baea81..680645a5d 100644
--- a/mcp-bom/pom.xml
+++ b/mcp-bom/pom.xml
@@ -27,6 +27,11 @@
     <dependencyManagement>
         <dependencies>
             <!-- Core MCP -->
+            <dependency>
+                <groupId>io.modelcontextprotocol.sdk</groupId>
+                <artifactId>mcp-spec-schema</artifactId>
+                <version>${project.version}</version>
+            </dependency>
             <dependency>
                 <groupId>io.modelcontextprotocol.sdk</groupId>
                 <artifactId>mcp-core</artifactId>
diff --git a/mcp-core/pom.xml b/mcp-core/pom.xml
index 39b4c9dc7..087ac7bdf 100644
--- a/mcp-core/pom.xml
+++ b/mcp-core/pom.xml
@@ -70,7 +70,11 @@
             <artifactId>mcp-json</artifactId>
             <version>0.17.0-SNAPSHOT</version>
         </dependency>
-
+        <dependency>
+            <groupId>io.modelcontextprotocol.sdk</groupId>
+            <artifactId>mcp-spec-schema</artifactId>
+            <version>0.17.0-SNAPSHOT</version>
+        </dependency>
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-api</artifactId>
diff --git a/mcp-spec-schema/pom.xml b/mcp-spec-schema/pom.xml
new file mode 100644
index 000000000..3c15f77ee
--- /dev/null
+++ b/mcp-spec-schema/pom.xml
@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>io.modelcontextprotocol.sdk</groupId>
+        <artifactId>mcp-parent</artifactId>
+        <version>0.17.0-SNAPSHOT</version>
+    </parent>
+
+    <groupId>io.modelcontextprotocol.sdk</groupId>
+    <artifactId>mcp-spec-schema</artifactId>
+    <version>0.17.0-SNAPSHOT</version>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-annotations</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.modelcontextprotocol.sdk</groupId>
+            <artifactId>mcp-json</artifactId>
+            <version>0.17.0-SNAPSHOT</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>${slf4j-api.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+            <version>1.0.0</version>
+        </dependency>
+    </dependencies>
+</project>
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpSchema.java b/mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/McpSchema.java
similarity index 100%
rename from mcp-core/src/main/java/io/modelcontextprotocol/spec/McpSchema.java
rename to mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/McpSchema.java
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/spec/ProtocolVersions.java b/mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/ProtocolVersions.java
similarity index 100%
rename from mcp-core/src/main/java/io/modelcontextprotocol/spec/ProtocolVersions.java
rename to mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/ProtocolVersions.java
diff --git a/mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/package-info.java b/mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/package-info.java
new file mode 100644
index 000000000..899a7c1e8
--- /dev/null
+++ b/mcp-spec-schema/src/main/java/io/modelcontextprotocol/spec/package-info.java
@@ -0,0 +1,4 @@
+/**
+ * The Model Context Protocol (MCP) specification package.
+ */
+package io.modelcontextprotocol.spec;
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/util/Assert.java b/mcp-spec-schema/src/main/java/io/modelcontextprotocol/util/Assert.java
similarity index 98%
rename from mcp-core/src/main/java/io/modelcontextprotocol/util/Assert.java
rename to mcp-spec-schema/src/main/java/io/modelcontextprotocol/util/Assert.java
index 1fa6b3058..85232d5b3 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/util/Assert.java
+++ b/mcp-spec-schema/src/main/java/io/modelcontextprotocol/util/Assert.java
@@ -4,9 +4,9 @@
 
 package io.modelcontextprotocol.util;
 
-import java.util.Collection;
+import org.jspecify.annotations.Nullable;
 
-import reactor.util.annotation.Nullable;
+import java.util.Collection;
 
 /**
  * Assertion utility class that assists in validating arguments.
diff --git a/pom.xml b/pom.xml
index ca9ce7be4..2de069290 100644
--- a/pom.xml
+++ b/pom.xml
@@ -104,6 +104,7 @@
 		<module>mcp-bom</module>
 		<module>mcp</module>
         <module>mcp-core</module>
+        <module>mcp-spec-schema</module>
         <module>mcp-json-jackson2</module>
         <module>mcp-json</module>
 		<module>mcp-spring/mcp-spring-webflux</module>