Approval

mcpygen.tool_exec.approval.client.ApprovalClient

ApprovalClient(
    callback: ApprovalCallback,
    host: str = "localhost",
    port: int = 8900,
)

Client for handling tool call approval requests.

ApprovalClient connects to a ToolServer's approval channel and receives approval requests. Each request is passed to the registered callback, which must accept or reject the request.

Example

async def on_approval_request(request: ApprovalRequest):
    print(f"Approval request: {request}")
    await request.accept()

async with ApprovalClient(callback=on_approval_request):
    # Execute code that triggers MCP tool calls
    ...

Parameters:

Name	Type	Description	Default
callback	ApprovalCallback	Async function called for each approval request.	required
host	str	Hostname of the ToolServer.	'localhost'
port	int	Port number of the ToolServer.	8900

connect async

connect()

Connect to a ToolServer's ApprovalChannel.

disconnect async

disconnect()

Disconnect from the ToolServer's ApprovalChannel.

mcpygen.tool_exec.approval.client.ApprovalRequest

ApprovalRequest(
    server_name: str,
    tool_name: str,
    tool_args: dict[str, Any],
    respond: Callable[[bool], Awaitable[None]],
)

An MCP tool call approval request.

ApprovalRequest instances are passed to the approval callback registered with ApprovalClient. The callback must call accept or reject for making an approval decision. Consumers can await response to observe the decision.

Example

async def on_approval_request(request: ApprovalRequest):
    print(f"Approval request: {request}")
    if request.tool_name == "dangerous_tool":
        await request.reject()
    else:
        await request.accept()

Parameters:

Name	Type	Description	Default
server_name	str	Name of the MCP server providing the tool.	required
tool_name	str	Name of the tool to execute.	required
tool_args	dict[str, Any]	Arguments to pass to the tool.	required
respond	Callable[[bool], Awaitable[None]]	Function to make an approval decision.	required

server_name instance-attribute

server_name = server_name

tool_name instance-attribute

tool_name = tool_name

tool_args instance-attribute

tool_args = tool_args

accept async

accept()

Accept the approval request.

reject async

reject()

Reject the approval request.

response async

response() -> bool

Wait for and return the approval decision.

mcpygen.tool_exec.client.ToolRunnerError

Bases: Exception

Raised when tool execution fails on the server.

mcpygen.tool_exec.client.ApprovalRejectedError

Bases: ToolRunnerError

Raised when a tool call is rejected by the approval workflow.

mcpygen.tool_exec.client.ApprovalTimeoutError

Bases: ToolRunnerError

Raised when an approval request times out.