fix: trim persisted tool results and sanitize MCP schemas

src/services/api/openaiSchemaSanitizer.ts

@@ -0,0 +1,216 @@
+function isSchemaRecord(value: unknown): value is Record<string, unknown> {
+  return value !== null && typeof value === 'object' && !Array.isArray(value)
+}
+
+function deepEqualJsonValue(a: unknown, b: unknown): boolean {
+  if (Object.is(a, b)) return true
+  if (typeof a !== typeof b) return false
+
+  if (Array.isArray(a) && Array.isArray(b)) {
+    return (
+      a.length === b.length &&
+      a.every((value, index) => deepEqualJsonValue(value, b[index]))
+    )
+  }
+
+  if (isSchemaRecord(a) && isSchemaRecord(b)) {
+    const aKeys = Object.keys(a)
+    const bKeys = Object.keys(b)
+    return (
+      aKeys.length === bKeys.length &&
+      aKeys.every(key => key in b && deepEqualJsonValue(a[key], b[key]))
+    )
+  }
+
+  return false
+}
+
+function matchesJsonSchemaType(type: string, value: unknown): boolean {
+  switch (type) {
+    case 'string':
+      return typeof value === 'string'
+    case 'number':
+      return typeof value === 'number' && Number.isFinite(value)
+    case 'integer':
+      return typeof value === 'number' && Number.isInteger(value)
+    case 'boolean':
+      return typeof value === 'boolean'
+    case 'object':
+      return value !== null && typeof value === 'object' && !Array.isArray(value)
+    case 'array':
+      return Array.isArray(value)
+    case 'null':
+      return value === null
+    default:
+      return true
+  }
+}
+
+function getJsonSchemaTypes(record: Record<string, unknown>): string[] {
+  const raw = record.type
+  if (typeof raw === 'string') {
+    return [raw]
+  }
+  if (Array.isArray(raw)) {
+    return raw.filter((value): value is string => typeof value === 'string')
+  }
+  return []
+}
+
+function schemaAllowsValue(schema: Record<string, unknown>, value: unknown): boolean {
+  if (Array.isArray(schema.anyOf)) {
+    return schema.anyOf.some(item =>
+      schemaAllowsValue(sanitizeSchemaForOpenAICompat(item), value),
+    )
+  }
+
+  if (Array.isArray(schema.oneOf)) {
+    return (
+      schema.oneOf.filter(item =>
+        schemaAllowsValue(sanitizeSchemaForOpenAICompat(item), value),
+      ).length === 1
+    )
+  }
+
+  if (Array.isArray(schema.allOf)) {
+    return schema.allOf.every(item =>
+      schemaAllowsValue(sanitizeSchemaForOpenAICompat(item), value),
+    )
+  }
+
+  if ('const' in schema && !deepEqualJsonValue(schema.const, value)) {
+    return false
+  }
+
+  if (Array.isArray(schema.enum)) {
+    if (!schema.enum.some(item => deepEqualJsonValue(item, value))) {
+      return false
+    }
+  }
+
+  const types = getJsonSchemaTypes(schema)
+  if (types.length > 0 && !types.some(type => matchesJsonSchemaType(type, value))) {
+    return false
+  }
+
+  return true
+}
+
+function sanitizeTypeField(record: Record<string, unknown>): void {
+  const allowed = new Set([
+    'string',
+    'number',
+    'integer',
+    'boolean',
+    'object',
+    'array',
+    'null',
+  ])
+
+  const raw = record.type
+  if (typeof raw === 'string') {
+    if (!allowed.has(raw)) delete record.type
+    return
+  }
+
+  if (!Array.isArray(raw)) return
+
+  const filtered = raw.filter(
+    (value, index): value is string =>
+      typeof value === 'string' &&
+      allowed.has(value) &&
+      raw.indexOf(value) === index,
+  )
+
+  if (filtered.length === 0) {
+    delete record.type
+  } else if (filtered.length === 1) {
+    record.type = filtered[0]
+  } else {
+    record.type = filtered
+  }
+}
+
+/**
+ * Sanitize loose/invalid JSON Schema into a form OpenAI-compatible providers
+ * are more likely to accept. This is intentionally defensive for external MCP
+ * servers that may advertise imperfect schemas.
+ */
+export function sanitizeSchemaForOpenAICompat(
+  schema: unknown,
+): Record<string, unknown> {
+  if (!isSchemaRecord(schema)) {
+    return {}
+  }
+
+  const record = { ...schema }
+
+  delete record.$schema
+  delete record.propertyNames
+
+  sanitizeTypeField(record)
+
+  if (isSchemaRecord(record.properties)) {
+    const sanitizedProps: Record<string, unknown> = {}
+    for (const [key, value] of Object.entries(record.properties)) {
+      sanitizedProps[key] = sanitizeSchemaForOpenAICompat(value)
+    }
+    record.properties = sanitizedProps
+  }
+
+  if ('items' in record) {
+    if (Array.isArray(record.items)) {
+      record.items = record.items.map(item =>
+        sanitizeSchemaForOpenAICompat(item),
+      )
+    } else {
+      record.items = sanitizeSchemaForOpenAICompat(record.items)
+    }
+  }
+
+  for (const key of ['anyOf', 'oneOf', 'allOf'] as const) {
+    if (Array.isArray(record[key])) {
+      record[key] = record[key].map(item =>
+        sanitizeSchemaForOpenAICompat(item),
+      )
+    }
+  }
+
+  if (Array.isArray(record.required) && isSchemaRecord(record.properties)) {
+    record.required = record.required.filter(
+      (value): value is string =>
+        typeof value === 'string' && value in record.properties,
+    )
+  }
+
+  const schemaWithoutEnum = { ...record }
+  delete schemaWithoutEnum.enum
+
+  if (Array.isArray(record.enum)) {
+    const filteredEnum = record.enum.filter(value =>
+      schemaAllowsValue(schemaWithoutEnum, value),
+    )
+    if (filteredEnum.length > 0) {
+      record.enum = filteredEnum
+    } else {
+      delete record.enum
+    }
+  }
+
+  const schemaWithoutConst = { ...record }
+  delete schemaWithoutConst.const
+  if ('const' in record && !schemaAllowsValue(schemaWithoutConst, record.const)) {
+    delete record.const
+  }
+
+  const schemaWithoutDefault = { ...record }
+  delete schemaWithoutDefault.default
+  if (
+    'default' in record &&
+    !schemaAllowsValue(schemaWithoutDefault, record.default)
+  ) {
+    delete record.default
+  }
+
+  return record
+}