fix: wrap non-object values in toolJson, add e2e smoke test

The MCP SDK rejects tools/call results where structuredContent is not a
record — array returns from list_products triggered an MCP error code
-32602. toolJson now wraps arrays/primitives as { result: <value> }.

scripts/smoke-test.ts spawns the built server over stdio, calls each
read-side tool against the live DB and asserts shape — surfaces this
bug class before regressions ship.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/smoke-test.ts

@@ -0,0 +1,97 @@
+// One-shot e2e smoke test against the live Scrum4Me database.
+// Reads .env, spawns the built server over stdio, calls each tool.
+//
+//   npm run build && npx tsx scripts/smoke-test.ts
+//
+// Exits 0 on success, 1 on any tool failure.
+
+import { Client } from '@modelcontextprotocol/sdk/client/index.js'
+import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js'
+import { readFileSync } from 'fs'
+import { resolve } from 'path'
+
+function loadEnv(): Record<string, string> {
+  const file = readFileSync(resolve(process.cwd(), '.env'), 'utf8')
+  const out: Record<string, string> = {}
+  for (const line of file.split('\n')) {
+    const m = line.match(/^([A-Z_][A-Z0-9_]*)=(.*)$/)
+    if (m) out[m[1]] = m[2].replace(/^"(.*)"$/, '$1')
+  }
+  return out
+}
+
+async function callTool(client: Client, name: string, args: Record<string, unknown> = {}) {
+  const res = await client.callTool({ name, arguments: args })
+  const text = (res.content as Array<{ type: string; text?: string }>)
+    .filter((c) => c.type === 'text')
+    .map((c) => c.text)
+    .join('\n')
+  return { isError: Boolean(res.isError), text }
+}
+
+async function main() {
+  const env = { ...process.env, ...loadEnv() } as Record<string, string>
+  if (!env.DATABASE_URL) throw new Error('DATABASE_URL missing')
+  if (!env.SCRUM4ME_TOKEN) throw new Error('SCRUM4ME_TOKEN missing')
+
+  const transport = new StdioClientTransport({
+    command: 'node',
+    args: ['dist/index.js'],
+    env,
+  })
+  const client = new Client({ name: 'smoke-test', version: '0.0.1' })
+  await client.connect(transport)
+
+  let failed = 0
+  const log = (label: string, ok: boolean, detail: string) => {
+    const tag = ok ? 'PASS' : 'FAIL'
+    console.log(`[${tag}] ${label}: ${detail.slice(0, 240)}${detail.length > 240 ? '…' : ''}`)
+    if (!ok) failed++
+  }
+
+  // tools/list
+  const tools = await client.listTools()
+  log(
+    'tools/list',
+    tools.tools.length === 9,
+    `${tools.tools.length} tools: ${tools.tools.map((t) => t.name).join(', ')}`,
+  )
+
+  // health
+  const health = await callTool(client, 'health')
+  log('health', !health.isError, health.text)
+  const healthJson = JSON.parse(health.text)
+  log('health.database', healthJson.database === 'ok', `database=${healthJson.database}`)
+
+  // list_products
+  const products = await callTool(client, 'list_products')
+  log('list_products', !products.isError, products.text)
+  const productList = JSON.parse(products.text) as Array<{ id: string; name: string; code: string | null }>
+  log('list_products.count', productList.length > 0, `count=${productList.length}`)
+
+  if (productList.length > 0) {
+    const productId = productList[0].id
+    const ctx = await callTool(client, 'get_claude_context', { product_id: productId })
+    log('get_claude_context', !ctx.isError, ctx.text)
+  }
+
+  // prompts/list
+  const prompts = await client.listPrompts()
+  log(
+    'prompts/list',
+    prompts.prompts.some((p) => p.name === 'implement_next_story'),
+    `prompts: ${prompts.prompts.map((p) => p.name).join(', ')}`,
+  )
+
+  await client.close()
+  if (failed > 0) {
+    console.error(`\n${failed} check(s) failed`)
+    process.exit(1)
+  }
+  console.log('\nall checks passed')
+}
+
+main().catch((err) => {
+  console.error('fatal:', err)
+  process.exit(1)
+})

src/errors.ts

@@ -19,9 +19,16 @@ export function toolError(message: string): CallToolResult {
 }
 
 export function toolJson(value: unknown): CallToolResult {
+  const text = JSON.stringify(value, null, 2)
+  // structuredContent must be a JSON object per the MCP spec — wrap arrays
+  // and primitives so the SDK's response validator accepts them.
+  const structured: Record<string, unknown> =
+    value !== null && typeof value === 'object' && !Array.isArray(value)
+      ? (value as Record<string, unknown>)
+      : { result: value }
   return {
-    content: [{ type: 'text', text: JSON.stringify(value, null, 2) }],
-    structuredContent: value as Record<string, unknown>,
+    content: [{ type: 'text', text }],
+    structuredContent: structured,
   }
 }