Harden server stability and fix MCP protocol hygiene

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    name: test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+      - run: npm ci
+      - run: npx tsc --noEmit
+      - run: npm run build

src/cli.ts

@@ -23,7 +23,9 @@ function checkEnvironmentVariables() {
 
 // Main function to run the MCP server
 async function main() {
-  console.log('Starting WordPress MCP Server...');
+  // stderr only: the spawned server inherits this process's stdio, so stdout
+  // belongs to the MCP JSON-RPC channel and must stay clean.
+  console.error('Starting WordPress MCP Server...');
 
   // Check for .env file in current directory
   const envPath = path.join(process.cwd(), '.env');

src/server.ts

@@ -10,16 +10,17 @@ import { z } from 'zod';
 import { zodToJsonSchema } from 'zod-to-json-schema';
 
 
-// Create MCP server instance
+// Create MCP server instance.
+// capabilities.tools must be the capability flags object, NOT a map of tool
+// definitions — server.tool() registration below handles tool advertisement.
+// Stuffing tool objects here serialized their zod schemas into every
+// initialize response (~65KB of internals per connection).
 const server = new McpServer({
     name: "wordpress",
     version: "0.0.1"
 }, {
     capabilities: {
-        tools: allTools.reduce((acc, tool) => {
-            acc[tool.name] = tool;
-            return acc;
-        }, {} as Record<string, any>)
+        tools: {}
     }
 });
 
@@ -40,22 +41,10 @@ for (const tool of allTools) {
         };
     };
 
-    // console.log(`Registering tool: ${tool.name}`);
-    // console.log(`Input schema: ${JSON.stringify(tool.inputSchema)}`);
-
-    // const zodSchema = z.any().optional();
-    // const jsonSchema = zodToJsonSchema(z.object(tool.inputSchema.properties as z.ZodRawShape));
-
-    // const schema = z.object(tool.inputSchema as z.ZodRawShape).catchall(z.unknown());
-
-    // The inputSchema is already in JSON Schema format with properties
-    // server.tool(tool.name, tool.inputSchema.shape, wrappedHandler);
-    // const zodSchema = z.any().optional();
-    // const jsonSchema = zodToJsonSchema(z.object(tool.inputSchema.properties as z.ZodRawShape));
-    // const parsedSchema = z.any().optional().parse(jsonSchema);
-
-    const zodSchema = z.object(tool.inputSchema.properties as z.ZodRawShape); 
-    server.tool(tool.name, zodSchema.shape, wrappedHandler)
+    // Tool modules define inputSchema.properties as zod shapes (see CLAUDE.md);
+    // passing raw JSON Schema here collapses the published schema to {}.
+    const zodSchema = z.object(tool.inputSchema.properties as z.ZodRawShape);
+    server.tool(tool.name, tool.description ?? '', zodSchema.shape, wrappedHandler)
 
 }
 
@@ -100,12 +89,20 @@ process.on('SIGINT', () => {
     process.exit(0);
 });
 process.on('uncaughtException', (error) => {
-    process.stderr.write(`[FATAL] Uncaught exception: ${error}\n`);
+    process.stderr.write(`[FATAL] Uncaught exception: ${error instanceof Error ? error.stack || error.message : error}\n`);
     process.exit(1);
 });
-process.on('unhandledRejection', (error) => {
-    process.stderr.write(`[FATAL] Unhandled rejection: ${error}\n`);
-    process.exit(1);
+// Do NOT exit on unhandled rejections: a stray promise rejection (e.g. a
+// background axios call outside a handler's try/catch) is not worth killing
+// the whole server over — that surfaces in clients as the server abruptly
+// disconnecting. Log it loudly instead.
+process.on('unhandledRejection', (reason) => {
+    process.stderr.write(`[ERROR] Unhandled rejection (server continuing): ${reason instanceof Error ? reason.stack || reason.message : reason}\n`);
+});
+// Always leave a trace of WHY the process is exiting, so client-side
+// "transport closed unexpectedly" messages can be correlated with a cause.
+process.on('exit', (code) => {
+    process.stderr.write(`[SHUTDOWN] Process exiting with code ${code}\n`);
 });
 
 main().catch((error) => {