fix: trim persisted tool results and sanitize MCP schemas

src/utils/toolResultStorage.test.ts

@@ -0,0 +1,54 @@
+import { expect, test } from 'bun:test'
+
+import { createUserMessage } from './messages.ts'
+import { applyToolResultReplacementsToMessages } from './toolResultStorage.ts'
+
+test('applyToolResultReplacementsToMessages replaces matching tool results and preserves unrelated messages', () => {
+  const unrelated = createUserMessage({ content: 'keep me' })
+  const oversizedResult = createUserMessage({
+    content: [
+      {
+        type: 'tool_result',
+        tool_use_id: 'tool-1',
+        content: 'very large tool output',
+        is_error: false,
+      },
+    ],
+  })
+  const messages = [unrelated, oversizedResult]
+  const replacement =
+    '<persisted-output>\nOutput too large. Preview\n</persisted-output>'
+
+  const next = applyToolResultReplacementsToMessages(
+    messages,
+    new Map([['tool-1', replacement]]),
+  )
+
+  expect(next).not.toBe(messages)
+  expect(next[0]).toBe(unrelated)
+  expect(next[1]).not.toBe(oversizedResult)
+  expect((next[1]!.message.content as Array<{ content: string }>)[0]!.content).toBe(
+    replacement,
+  )
+})
+
+test('applyToolResultReplacementsToMessages is idempotent when messages are already hydrated', () => {
+  const hydrated = createUserMessage({
+    content: [
+      {
+        type: 'tool_result',
+        tool_use_id: 'tool-1',
+        content: '<persisted-output>\nPreview\n</persisted-output>',
+        is_error: false,
+      },
+    ],
+  })
+  const messages = [hydrated]
+
+  const next = applyToolResultReplacementsToMessages(
+    messages,
+    new Map([['tool-1', '<persisted-output>\nPreview\n</persisted-output>']]),
+  )
+
+  expect(next).toBe(messages)
+})