list_sources and get_source_info fail due to incorrect response schema validation

[AaruniAggarwal]

The MCP tools list_sources and get_source_info consistently fail with response validation errors, even though the underlying Unstructured API calls succeed.

The failure occurs during response unmarshalling, not during request handling.

Both tools return errors similar to:
Error executing tool <tool_name>: Response validation failed
<multiple> validation errors for Unmarshaller
body.config.<ConnectorConfig>.<required_field>\n  Field require

The errors reference required fields from multiple connector config schemas (e.g. Box, MongoDB, S3, Azure, etc.), even when the source being returned uses only a single connector type.

[AaruniAggarwal]

Created one connector of type slack and then tried using tools like list_sources and get_source_info using the APIs. But they are returning following error.

curl request used:

curl -X POST \
  "http://unstructured-mcp-model-deploy.apps.rdr-rhoai-comp.ibm.com/messages/?session_id=c53695e139a24a7897f3d0d5d35d3cf9" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 100,
    "method": "tools/call",
    "params": {
      "name": "list_sources",
      "arguments": {
        "source_type": null
      }
    }
  }'

curl -X POST \
  "http://unstructured-mcp-model-deploy.apps.rdr-rhoai-comp.ibm.com/messages/?session_id=c9224f04ec584f92b7e51d0478c6771d" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 102,
    "method": "tools/call",
    "params": {
      "name": "get_source_info",
      "arguments": {
        "source_id": "<source-id>"
      }
    }
  }'

response:

event: message
data: {"jsonrpc":"2.0","id":100,"result":{"content":[{"type":"text","text":"Error executing tool list_sources: Response validation failed: 87 validation errors for Unmarshaller\nbody.0.config.BoxSourceConnectorConfig.box_app_config\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.BoxSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.MongoDBConnectorConfig.collection\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.MongoDBConnectorConfig.database\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.MongoDBConnectorConfig.uri\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DropboxSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DropboxSourceConnectorConfig.remote_url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ElasticsearchConnectorConfig.es_api_key\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ElasticsearchConnectorConfig.hosts\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ElasticsearchConnectorConfig.index_name\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.GCSSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.GCSSourceConnectorConfig.remote_url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.GCSSourceConnectorConfig.service_account_key\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SalesforceSourceConnectorConfig.categories\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SalesforceSourceConnectorConfig.consumer_key\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SalesforceSourceConnectorConfig.private_key\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SalesforceSourceConnectorConfig.username\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.GoogleDriveSourceConnectorConfig.drive_id\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.GoogleDriveSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.GoogleDriveSourceConnectorConfig.service_account_key\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ZendeskSourceConnectorConfig.api_token\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ZendeskSourceConnectorConfig.email\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ZendeskSourceConnectorConfig.subdomain\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.AzureSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.AzureSourceConnectorConfig.remote_url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.authority_url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.client_cred\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.client_id\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.path\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.tenant\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OneDriveSourceConnectorConfig.user_pname\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.KafkaCloudSourceConnectorConfig.bootstrap_servers\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.KafkaCloudSourceConnectorConfig.kafka_api_key\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.KafkaCloudSourceConnectorConfig.num_messages_to_consume\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.KafkaCloudSourceConnectorConfig.port\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.KafkaCloudSourceConnectorConfig.secret\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.KafkaCloudSourceConnectorConfig.topic\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DatabricksVolumesConnectorConfig.catalog\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DatabricksVolumesConnectorConfig.client_id\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DatabricksVolumesConnectorConfig.client_secret\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DatabricksVolumesConnectorConfig.host\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DatabricksVolumesConnectorConfig.volume\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.DatabricksVolumesConnectorConfig.volume_path\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OutlookSourceConnectorConfig.client_cred\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OutlookSourceConnectorConfig.client_id\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OutlookSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.OutlookSourceConnectorConfig.user_email\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.S3SourceConnectorConfig.anonymous\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.S3SourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.S3SourceConnectorConfig.remote_url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SharePointSourceConnectorConfig.client_cred\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SharePointSourceConnectorConfig.client_id\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SharePointSourceConnectorConfig.recursive\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SharePointSourceConnectorConfig.site\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SharePointSourceConnectorConfig.tenant\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SharePointSourceConnectorConfig.user_pname\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.CouchbaseSourceConnectorConfig.batch_size\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.CouchbaseSourceConnectorConfig.bucket\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.CouchbaseSourceConnectorConfig.collection_id\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.CouchbaseSourceConnectorConfig.connection_string\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.CouchbaseSourceConnectorConfig.password\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.CouchbaseSourceConnectorConfig.username\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.batch_size\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.database\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.host\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.id_column\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.password\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.port\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.table_name\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.PostgresSourceConnectorConfig.username\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.JiraSourceConnectorConfig.url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.JiraSourceConnectorConfig.username\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ConfluenceSourceConnectorConfig.cloud\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ConfluenceSourceConnectorConfig.max_num_of_docs_from_each_space\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ConfluenceSourceConnectorConfig.max_num_of_spaces\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ConfluenceSourceConnectorConfig.spaces\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ConfluenceSourceConnectorConfig.url\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.ConfluenceSourceConnectorConfig.username\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.account\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.database\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.host\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.id_column\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.password\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.role\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.table_name\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing\nbody.0.config.SnowflakeSourceConnectorConfig.user\n  Field required [type=missing, input_value={'token': '**********', '...art_date': '2026-01-09'}, input_type=dict]\n    For further information visit https://errors.pydantic.dev/2.12/v/missing"}],"isError":true}}

Though tools like list_workflows and list_destinations works fine.