Simplify SQL error messages

src/core/query/sql.js

@@ -48,13 +48,10 @@ export async function executeQuerySql(args) {
       try {
         const trimmed = query.trim()
         if (trimmed.length === 0) throw new Error('SQL query is required')
-        let statement
-        try {
-          statement = parseSql({ query: trimmed })
-        } catch (err) {
-          const message = err instanceof Error ? err.message : String(err)
-          throw new Error(`SQL must be a single read-only SELECT statement: ${message}`)
-        }
+        // squirreling only parses read-only SELECTs, so its own error message
+        // already points at the real problem (syntax error, unknown function,
+        // non-SELECT statement). Surface it verbatim rather than wrapping it.
+        const statement = parseSql({ query: trimmed })
 
         const tableNames = uniqueStrings(extractTables(statement))
         span.setAttribute('table_count', tableNames.length)

test/core/query-sql-error.test.js

@@ -0,0 +1,37 @@
+// @ts-check
+
+import test from 'node:test'
+import assert from 'node:assert/strict'
+
+import { executeQuerySql } from '../../src/core/query/sql.js'
+
+/** Minimal registry/storage stubs — parse failures fire before either is used. */
+const registry = { getDataset: () => null, listDatasets: () => [] }
+const storage = { cacheRoot: '/tmp/hypaware-test', pendingInfo: async () => ({ pending: false }) }
+
+/** @param {string} query */
+async function runExpectError(query) {
+  try {
+    await executeQuerySql({ query, registry: /** @type {any} */ (registry), storage: /** @type {any} */ (storage) })
+  } catch (err) {
+    return err instanceof Error ? err.message : String(err)
+  }
+  throw new Error(`expected ${JSON.stringify(query)} to throw`)
+}
+
+test('parse errors surface the squirreling message verbatim, unwrapped', async () => {
+  const message = await runExpectError('SELECT foo(1)')
+  assert.match(message, /Unknown function "foo"/)
+  assert.doesNotMatch(message, /single read-only SELECT/)
+})
+
+test('non-SELECT statements surface the parser message without extra framing', async () => {
+  const message = await runExpectError('INSERT INTO t VALUES (1)')
+  assert.match(message, /Expected SELECT but found "INSERT"/)
+  assert.doesNotMatch(message, /single read-only SELECT/)
+})
+
+test('empty SQL is reported as required', async () => {
+  const message = await runExpectError('   ')
+  assert.match(message, /SQL query is required/)
+})