Add support for "object" type parameters in tool manifests

[komatsuna4747]

Prerequisites

• Search the current open issues

What are you trying to do that currently feels hard or impossible?

I'm using toolbox-core v0.4.0.
When loading the looker-query tool (or other tools that declare parameters with type: "object"), the toolbox client raises a ValueError during initialization.

Example manifest

sources:
  my-looker-source:
    kind: looker
    base_url: http://looker.example.com
    client_id: ${LOOKER_CLIENT_ID}
    client_secret: ${LOOKER_CLIENT_SECRET}
    verify_ssl: true
    timeout: 600s
tools:
  execute_query:
    kind: looker-query
    source: my-looker-source
    description: |
      Executes a query against the Looker instance and returns the results.
toolsets:
  my-looker-toolset:
    - execute_query

Code to reproduce

from toolbox_core import ToolboxSyncClient
client = ToolboxSyncClient("http://127.0.0.1:5000")
tools = client.load_toolset("my-looker-toolset")

Error

ValueError: Unsupported schema type: object

Looker queries often require a filters dictionary with dynamic key-value pairs. Without native support for the "object" type, users must resort to workarounds like JSON-encoded strings or key-value arrays, which compromise type safety and developer experience.

Suggested Solution(s)

Extend the type mapping in protocol.py to handle "object" types by mapping them to Python's dict type, similar to how "array" types are currently handled.

mcp-toolbox-sdk-python/packages/toolbox-core/src/toolbox_core/protocol.py

Lines 33 to 48 in 43c671b

	def __get_type(self) -> Type:
	base_type: Type
	if self.type == "string":
	base_type = str
	elif self.type == "integer":
	base_type = int
	elif self.type == "float":
	base_type = float
	elif self.type == "boolean":
	base_type = bool
	elif self.type == "array":
	if self.items is None:
	raise Exception("Unexpected value: type is 'list' but items is None")
	base_type = list[self.items.__get_type()] # type: ignore
	else:
	raise ValueError(f"Unsupported schema type: {self.type}")

If the "object" type was intentionally omitted from the supported types for specific reasons, please let me know so I can better understand the design constraints and explore alternative solutions.

Alternatives Considered

No response

Additional Details

No response

[ngocquang2797]

i have same issue with tools looker-query and looker-query-sql

[anubhav756]

Thanks for raising the bug @komatsuna4747!

This is a feature we definitely want to add. We believe it's crucial to implement "object" type support across all Toolbox SDKs to ensure a consistent and robust developer experience.

We'll be prioritizing this and will work to get it implemented as soon as possible.

[anubhav756]

Quick update: MCP Toolbox supports the new map type params (#928).

#324 adds support for this new param type in the SDKs.