small fixes

Author: ihrpr

src/server/mcp.test.ts

@@ -1203,72 +1203,68 @@ describe("tool()", () => {
  }),
  ).rejects.toThrow(/Tool test has an output schema but no structured content was provided/);
  });
-
- /***
+ /***
  * Test: Tool with Output Schema Must Provide Structured Content
  */
- test("should not throw error when tool with outputSchema returns no structuredContent and isError is true", async () => {
- const mcpServer = new McpServer({
- name: "test server",
- version: "1.0",
- });
- 
- const client = new Client({
- name: "test client",
- version: "1.0",
- });
- 
- // Register a tool with outputSchema that returns only content without structuredContent
- mcpServer.registerTool(
- "test",
- {
- description: "Test tool with output schema but missing structured content",
- inputSchema: {
- input: z.string(),
- },
- outputSchema: {
- processedInput: z.string(),
- resultType: z.string(),
- },
+ test("should skip outputSchema validation when isError is true", async () => {
+ const mcpServer = new McpServer({
+ name: "test server",
+ version: "1.0",
+ });
+
+ const client = new Client({
+ name: "test client",
+ version: "1.0",
+ });
+
+ mcpServer.registerTool(
+ "test",
+ {
+ description: "Test tool with output schema but missing structured content",
+ inputSchema: {
+ input: z.string(),
  },
- async ({ input }) => ({
- // Only return content without structuredContent
- content: [
- {
- type: "text",
- text: `Processed: ${input}`,
- },
- ],
- isError: true,
- })
- );
- 
- const [clientTransport, serverTransport] =
- InMemoryTransport.createLinkedPair();
- 
- await Promise.all([
- client.connect(clientTransport),
- mcpServer.server.connect(serverTransport),
- ]);
- 
- // Call the tool and expect it to not throw an error
- await expect(
- client.callTool({
- name: "test",
- arguments: {
- input: "hello",
- },
- }),
- ).resolves.toStrictEqual({
+ outputSchema: {
+ processedInput: z.string(),
+ resultType: z.string(),
+ },
+ },
+ async ({ input }) => ({
  content: [
  {
  type: "text",
- text: `Processed: hello`,
+ text: `Processed: ${input}`,
  },
  ],
  isError: true,
- });
+ })
+ );
+
+ const [clientTransport, serverTransport] =
+ InMemoryTransport.createLinkedPair();
+
+ await Promise.all([
+ client.connect(clientTransport),
+ mcpServer.server.connect(serverTransport),
+ ]);
+
+ await expect(
+ client.callTool({
+ name: "test",
+ arguments: {
+ input: "hello",
+ },
+ }),
+ ).resolves.toStrictEqual({
+ content: [
+ {
+ type: "text",
+ text: `Processed: hello`,
+ },
+ ],
+ isError: true,
  });
+ });
 
  /***
  * Test: Schema Validation Failure for Invalid Structured Content

src/server/mcp.ts

@@ -200,7 +200,7 @@ export class McpServer {
  }
  }
 
- if (tool.outputSchema && (result.isError !== true)) {
+ if (tool.outputSchema && !result.isError) {
  if (!result.structuredContent) {
  throw new McpError(
  ErrorCode.InvalidParams,