iPhone composeExtension/fetchTask invoke omits commandContext and breaks Microsoft.Teams SDK deserialization

[gauravsarwal]

Bug report

When opening a Teams message extension action command from iPhone, the invoke payload can omit value.commandContext.

With:

• Microsoft.Teams.Plugins.AspNetCore 2.0.9
• Microsoft.Teams.Extensions.Graph 2.0.9

the request fails during deserialization before app handlers run.

Actual behavior

The SDK throws:

System.Text.Json.JsonException: JSON deserialization for type 'Microsoft.Teams.Api.MessageExtensions.Action' was missing required properties including: 'commandContext'.

This happens in Microsoft.Teams.Plugins.AspNetCore.AspNetCorePlugin.ParseActivity(...).

Expected behavior

Either:

• Teams mobile should always send commandContext, or
• the SDK should treat commandContext as optional for this invoke shape

Repro

1. Create a compose extension command with:
   • type: action
   • fetchTask: true
2. Open it from Teams web/desktop → works
3. Open the same command from Teams on iPhone → request may omit value.commandContext
4. SDK deserialization fails before handler execution

Working payload example

{ "name": "composeExtension/fetchTask", "value": { "commandId": "createTicket", "commandContext": "compose", "context": { "theme": "default" } } }

Failing payload example

{ "name": "composeExtension/fetchTask", "value": { "commandId": "createTicket", "context": { "theme": "dark" }, "state": "" } }

Workaround

Application-side middleware was required to inject a fallback commandContext before SDK deserialization.

Question

Is this a known Teams iPhone client issue, or should the SDK tolerate missing commandContext here?

[microsoft-github-policy-service]

Hi @gauravsarwal! We will investigate and if we require further information we will reach out to you. Please use this link to escalate if you don't get replies in two working days.

Best regards, Teams Platform

[m365-agent-toolkit-assistant]

👋 Hi gauravsarwal,

Thank you for reporting this issue! We want to let you know that:

⏱️ Our team will personally review your issue
🎯 You can expect a response within 1 business day

✨ This is an AI-generated initial response
🤖 AI-Generated Preliminary Analysis:

Classification: Upstream — the reported iPhone payload violates the documented Teams fetchTask contract before sample code runs.

• Microsoft Learn specifies value.commandContext for composeExtension/fetchTask.
• Teams SDK for .NET 2.0 marks CommandContext as required, explaining the pre-handler exception.
• Evidence currently suggests a Teams iOS payload issue; Microsoft acknowledgement or ownership is not yet established.

Upgrade check: No verified SDK release or changelog fix was found.

What to do now:

1. Keep the pre-deserialization fallback only when context can be safely inferred; don’t always assume compose.
2. Provide iOS version, Teams app version, invocation location, timestamp, tenant ID, and sanitized full activity.
3. Report the SDK-resilience request separately in microsoft/teams.net.

Useful links:

• Documented initial invoke payload
• SDK Action.CommandContext model
• No sufficiently relevant duplicate issue found.

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Note: This is an automated first response generated by AI. A human team member will review your issue and provide a more detailed response soon. We appreciate your patience!

[Prasad-MSFT]

Hi gauravsarwal thanks for raising your issue. We will check this at our end and will update you accordingly.

[Prasad-MSFT]

Update:
We have raised a bug for this issue. We will inform you once we get any further update from engineering team. Thanks!