test(core): cover the parseSchema contract

Assert add_connection advertises fullSchema as its inputSchema (never the
refined schema) and applies an optional parseSchema in the handler: a
refinement rejection surfaces as an error and skips registry.add, while a
passing config persists. Locks the wire/parse split at the core level.

packages/core/test/unit/mcp/connectionTools.test.ts

@@ -98,7 +98,7 @@ describe('registerConnectionTools', () => {
     let registry: FakeRegistry
     let manager: FakeManager
     let handlers: Map<string, Handler>
-    let configs: Map<string, { description?: string }>
+    let configs: Map<string, { description?: string; inputSchema?: unknown }>
 
     const invoke = (name: string, args: Record<string, unknown> = {}): Promise<CallToolResult> => {
         const handler = handlers.get(name)
@@ -113,7 +113,11 @@ describe('registerConnectionTools', () => {
         handlers = new Map()
         configs = new Map()
         vi.spyOn(server, 'registerTool').mockImplementation(
-            (name: string, config: { description?: string }, handler: unknown) => {
+            (
+                name: string,
+                config: { description?: string; inputSchema?: unknown },
+                handler: unknown
+            ) => {
                 configs.set(name, config)
                 handlers.set(name, handler as Handler)
                 return {
@@ -212,6 +216,34 @@ describe('registerConnectionTools', () => {
         expect(text(result)).toContain('already exists')
     })
 
+    it('add_connection advertises fullSchema and applies parseSchema in the handler', async () => {
+        const parseSchema = schema.superRefine((c, ctx) => {
+            if (c.host === 'bad') {
+                ctx.addIssue({ code: z.ZodIssueCode.custom, message: 'bad host' })
+            }
+        })
+        registry.add.mockImplementation((config: TestConfig) => resolved(config))
+        register({ parseSchema })
+
+        // The advertised wire schema is always fullSchema, never the refined one
+        // (a ZodEffects has no .shape and would publish an empty inputSchema).
+        expect(configs.get('add_connection')?.inputSchema).toBe(schema)
+
+        const rejected = await invoke('add_connection', { name: 'x', type: 'mysql', host: 'bad' })
+        expect(rejected.isError).toBe(true)
+        expect(text(rejected)).toContain('bad host')
+        expect(registry.add).not.toHaveBeenCalled()
+
+        const accepted = await invoke('add_connection', { name: 'y', type: 'mysql', host: 'good' })
+        expect(accepted.isError).toBeFalsy()
+        expect(registry.add).toHaveBeenCalledWith({
+            name: 'y',
+            type: 'mysql',
+            host: 'good',
+            readonly: false
+        })
+    })
+
     it('update_connection patches, invalidates the cache and returns the public view', async () => {
         registry.update.mockReturnValue(
             resolved({ name: 'c', type: 'postgres', host: 'new', readonly: false })