Fix resource link content helper

CHANGELOG.md

@@ -19,6 +19,7 @@
 - Remove dead code across the codebase.
 - (Fix) Fix logdev references in server logger.
 - (Fix) Ensure context hash keys are symbolized when retrieved from session.
+- (Fix) Fix `resource_link` content helper to return a Content object like all other content helpers.
 
 ## [0.6.0] - 2026-01-26
 

lib/model_context_protocol/server/content_helpers.rb

@@ -78,7 +78,7 @@ def resource_link(name:, uri:, meta: nil, annotations: {}, description: nil, mim
         size:,
         title:,
         uri:
-      ].serialized
+      ]
     end
   end
 end

spec/lib/model_context_protocol/server/content_helpers_spec.rb

@@ -217,45 +217,44 @@
 
   describe "#resource_link" do
     context "with valid data" do
-      it "returns a serialized ResourceLink hash with required parameters" do
+      it "returns a ResourceLink content object with required parameters" do
         result = helper.resource_link(name: "test-file", uri: "https://example.com/test.txt")
 
-        expect(result).to be_a(Hash)
-        expect(result[:name]).to eq("test-file")
-        expect(result[:uri]).to eq("https://example.com/test.txt")
-        expect(result[:type]).to eq("resource_link")
+        expect(result).to be_a(ModelContextProtocol::Server::Content::ResourceLink)
+        expect(result.name).to eq("test-file")
+        expect(result.uri).to eq("https://example.com/test.txt")
+        expect(result.meta).to be_nil
+        expect(result.annotations).to be_nil
       end
 
-      it "returns a serialized ResourceLink hash with meta" do
+      it "returns a ResourceLink content object with meta" do
         result = helper.resource_link(
           name: "test-file",
           uri: "https://example.com/test.txt",
           meta: {api_version: "v1"}
         )
 
-        expect(result).to be_a(Hash)
-        expect(result[:name]).to eq("test-file")
-        expect(result[:uri]).to eq("https://example.com/test.txt")
-        expect(result[:type]).to eq("resource_link")
-        expect(result[:_meta]).to eq({api_version: "v1"})
+        expect(result).to be_a(ModelContextProtocol::Server::Content::ResourceLink)
+        expect(result.name).to eq("test-file")
+        expect(result.uri).to eq("https://example.com/test.txt")
+        expect(result.meta).to eq({api_version: "v1"})
       end
 
-      it "returns a serialized ResourceLink hash with annotations" do
+      it "returns a ResourceLink content object with annotations" do
         annotations = {audience: "user", priority: 0.8}
         result = helper.resource_link(
           name: "test-file",
           uri: "https://example.com/test.txt",
           annotations: annotations
         )
 
-        expect(result).to be_a(Hash)
-        expect(result[:name]).to eq("test-file")
-        expect(result[:uri]).to eq("https://example.com/test.txt")
-        expect(result[:type]).to eq("resource_link")
-        expect(result[:annotations]).to eq({audience: "user", priority: 0.8})
+        expect(result).to be_a(ModelContextProtocol::Server::Content::ResourceLink)
+        expect(result.name).to eq("test-file")
+        expect(result.uri).to eq("https://example.com/test.txt")
+        expect(result.annotations).to eq({audience: "user", priority: 0.8})
       end
 
-      it "returns a serialized ResourceLink hash with all optional parameters" do
+      it "returns a ResourceLink content object with all optional parameters" do
         annotations = {audience: ["user", "assistant"], last_modified: "2025-01-12T15:00:58Z", priority: 1.0}
         result = helper.resource_link(
           name: "test-file",
@@ -268,40 +267,48 @@
           title: "Test File"
         )
 
-        expect(result).to be_a(Hash)
-        expect(result[:name]).to eq("test-file")
-        expect(result[:uri]).to eq("https://example.com/test.txt")
-        expect(result[:type]).to eq("resource_link")
-        expect(result[:_meta]).to eq({external: true})
-        expect(result[:annotations]).to eq({
+        expect(result).to be_a(ModelContextProtocol::Server::Content::ResourceLink)
+        expect(result.name).to eq("test-file")
+        expect(result.uri).to eq("https://example.com/test.txt")
+        expect(result.meta).to eq({external: true})
+        expect(result.annotations).to eq({
           audience: ["user", "assistant"],
           lastModified: "2025-01-12T15:00:58Z",
           priority: 1.0
         })
-        expect(result[:description]).to eq("A test file")
-        expect(result[:mimeType]).to eq("text/plain")
-        expect(result[:size]).to eq(1024)
-        expect(result[:title]).to eq("Test File")
+        expect(result.description).to eq("A test file")
+        expect(result.mime_type).to eq("text/plain")
+        expect(result.size).to eq(1024)
+        expect(result.title).to eq("Test File")
       end
 
-      it "returns a serialized ResourceLink hash with only some optional parameters" do
+      it "returns a ResourceLink content object with only some optional parameters" do
         result = helper.resource_link(
           name: "test-file",
           uri: "https://example.com/test.txt",
           description: "A test file",
           size: 2048
         )
 
-        expect(result).to be_a(Hash)
-        expect(result[:name]).to eq("test-file")
-        expect(result[:uri]).to eq("https://example.com/test.txt")
-        expect(result[:type]).to eq("resource_link")
-        expect(result[:description]).to eq("A test file")
-        expect(result[:size]).to eq(2048)
-        expect(result).not_to have_key(:_meta)
-        expect(result).not_to have_key(:annotations)
-        expect(result).not_to have_key(:mimeType)
-        expect(result).not_to have_key(:title)
+        expect(result).to be_a(ModelContextProtocol::Server::Content::ResourceLink)
+        expect(result.name).to eq("test-file")
+        expect(result.uri).to eq("https://example.com/test.txt")
+        expect(result.description).to eq("A test file")
+        expect(result.size).to eq(2048)
+        expect(result.meta).to be_nil
+        expect(result.annotations).to be_nil
+        expect(result.mime_type).to be_nil
+        expect(result.title).to be_nil
+      end
+
+      it "serializes correctly" do
+        result = helper.resource_link(name: "test-file", uri: "https://example.com/test.txt")
+        serialized = result.serialized
+
+        expect(serialized).to be_a(Hash)
+        expect(serialized[:name]).to eq("test-file")
+        expect(serialized[:uri]).to eq("https://example.com/test.txt")
+        expect(serialized[:type]).to eq("resource_link")
       end
     end
   end

spec/support/tools/test_tool_with_resource_link_response.rb

@@ -19,18 +19,12 @@ class TestToolWithResourceLinkResponse < ModelContextProtocol::Server::Tool
   def call
     name = arguments[:name]
 
-    # Create ResourceLink content object directly since the helper returns serialized form
-    link = ModelContextProtocol::Server::Content::ResourceLink[
-      meta: nil,
-      annotations: nil,
+    respond_with content: resource_link(
+      name: name,
+      uri: "file:///docs/#{name}.md",
       description: "A document named #{name}",
       mime_type: "text/markdown",
-      name: name,
-      size: nil,
-      title: "Document: #{name}",
-      uri: "file:///docs/#{name}.md"
-    ]
-
-    respond_with content: link
+      title: "Document: #{name}"
+    )
   end
 end

tasks/templates/dev-http-puma.erb

@@ -84,6 +84,7 @@ ModelContextProtocol::Server.with_streamable_http_transport do |config|
       register TestToolWithProgressableAndCancellable
       register TestToolWithAnnotations
       register TestToolWithSecuritySchemes
+      register TestToolWithResourceLinkResponse
       register TestToolWithAudioResponse if flag_enabled?('extra_tools')
     end
   end

tasks/templates/dev-http.erb

@@ -84,6 +84,7 @@ ModelContextProtocol::Server.with_streamable_http_transport do |config|
       register TestToolWithProgressableAndCancellable
       register TestToolWithAnnotations
       register TestToolWithSecuritySchemes
+      register TestToolWithResourceLinkResponse
       register TestToolWithAudioResponse if flag_enabled?('extra_tools')
     end
   end

tasks/templates/dev.erb

@@ -66,6 +66,7 @@ server = ModelContextProtocol::Server.with_stdio_transport do |config|
       register TestToolWithProgressableAndCancellable
       register TestToolWithAnnotations
       register TestToolWithSecuritySchemes
+      register TestToolWithResourceLinkResponse
     end
   end
 end