test: add regression test for restoring tools after discuss flow scoping

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/resources/extensions/gsd/tests/restore-tools-after-discuss.test.ts

@@ -0,0 +1,63 @@
+/**
+ * Regression test for #3628 — restore tool set after discuss flow scoping
+ *
+ * The discuss flow narrows the active tool set to avoid "grammar too complex"
+ * errors. Without restoring after sendMessage, the narrowed tools leaked into
+ * subsequent dispatches, breaking plan/execute flows.
+ *
+ * The fix saves the full tool set before scoping and restores it after
+ * sendMessage returns.
+ */
+
+import { describe, it } from 'node:test'
+import assert from 'node:assert/strict'
+import { readFileSync } from 'node:fs'
+import { resolve } from 'node:path'
+
+const src = readFileSync(
+  resolve(process.cwd(), 'src', 'resources', 'extensions', 'gsd', 'guided-flow.ts'),
+  'utf-8',
+)
+
+describe('restore tools after discuss flow scoping (#3628)', () => {
+  it('savedTools is declared before the discuss scoping block', () => {
+    // savedTools must be declared before the discuss-* check
+    const savedToolsDecl = src.indexOf('let savedTools')
+    const discussCheck = src.indexOf('if (unitType?.startsWith("discuss-"))')
+    assert.ok(savedToolsDecl !== -1, 'savedTools variable must be declared')
+    assert.ok(discussCheck !== -1, 'discuss-* type check must exist')
+    assert.ok(
+      savedToolsDecl < discussCheck,
+      'savedTools must be declared before the discuss scoping block',
+    )
+  })
+
+  it('savedTools captures current tools inside the discuss block', () => {
+    const discussCheck = src.indexOf('if (unitType?.startsWith("discuss-"))')
+    assert.ok(discussCheck !== -1)
+
+    // Look for savedTools assignment within the discuss block
+    const blockAfter = src.slice(discussCheck, discussCheck + 500)
+    assert.ok(
+      blockAfter.includes('savedTools = currentTools'),
+      'savedTools must be assigned from currentTools inside the discuss block',
+    )
+  })
+
+  it('savedTools is restored after sendMessage', () => {
+    // Find the sendMessage call
+    const sendMsg = src.indexOf('triggerTurn: true')
+    assert.ok(sendMsg !== -1, 'sendMessage with triggerTurn must exist')
+
+    // After sendMessage, savedTools should be restored via setActiveTools
+    const afterSend = src.slice(sendMsg, sendMsg + 500)
+    assert.ok(
+      afterSend.includes('if (savedTools)'),
+      'savedTools restoration guard must exist after sendMessage',
+    )
+    assert.ok(
+      afterSend.includes('setActiveTools(savedTools)'),
+      'setActiveTools(savedTools) must be called to restore the full tool set',
+    )
+  })
+})