Power Platform Community Forum Thread Details

Hi all — I’m testing an integration between Asana’s V2 MCP server and a Copilot Studio agent. I created an Asana MCP app, connected it to Copilot Studio with OAuth, and the server appears reachable. Asana documents that the V2 MCP server uses OAuth, and Copilot Studio documents that MCP tool inputs/outputs come from the connected MCP server.

The main problem is with task creation, not auth. When the agent tries to call create_tasks, I get this error:

MCP error -32602: Input validation error: Invalid arguments for tool create_tasks:
[
  {
    "code": "invalid_type",
    "expected": "array",
    "received": "object",
    "path": ["tasks"],
    "message": "Expected array, received object"
  }
]

In the Copilot Studio test pane, the tool input shows tasks(table) as required, which matches the validation error. The agent seems to be sending tasks as an object instead of an array/table inside the expected payload.

What’s confusing is that the model reasoning sometimes explicitly says it knows tasks should be an array, but the final call still fails validation. That makes this feel more like a request-shaping / tool-binding issue than an OAuth or endpoint issue. Copilot Studio says MCP tool schemas are surfaced from the MCP server, so I’m wondering whether anyone has seen a mismatch between the displayed tool schema and the actual payload being sent.

A few questions:

Has anyone successfully used Copilot Studio with Asana’s MCP create_tasks tool?

If so, what exact request shape is expected for create_tasks in this environment?

Has anyone seen Copilot Studio repeatedly pass tasks incorrectly even when the tool input shows tasks(table)?

Did you solve this through agent instructions, tool selection, or something else?

Any help would be appreciated — especially from anyone who has gotten write actions working reliably with the Asana MCP server in Copilot Studio.

Categories:

Calling actions from Copilot Studio

Model context protocol

Hi there! Great question — this is a nuanced MCP schema-binding issue.

What's happening

Copilot Studio surfaces MCP tool schemas directly from the connected MCP server (Asana's V2 MCP). When the tool schema declares tasks as a table (array), Copilot Studio should pass it as a JSON array. However, the generative orchestration layer sometimes serialises a single-item construct as a JSON object instead of a single-element array, which triggers Asana's -32602 validation error.

What Microsoft Learn says about MCP in Copilot Studio

According to the Extend your agent with Model Context Protocol documentation, tool inputs and outputs are shaped by the schema advertised by the MCP server, and Copilot Studio passes tool arguments based on that schema type.

Suggested workarounds to try

Add explicit instructions in your agent's system prompt — e.g., "When calling create_tasks, always pass tasks as a JSON array, even for a single task." Per Microsoft Learn, agent instructions can guide how the model shapes tool calls.
Wrap in a Power Automate flow — Create an agent flow that accepts individual task fields as parameters, then constructs the array internally before calling the Asana API. This gives full control over the payload shape.
Check the MCP server's JSON schema — Confirm the schema declares tasks with "type": "array" and test whether wrapping in an array via instructions resolves it.

⚠️ The precise request shape required by Asana's V2 MCP server is vendor-specific. For definitive schema documentation, refer to Asana's MCP server docs directly.

References

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Raghav Mishra — LinkedIn | PowerAI Labs