Foundry New endpoint protocol does not support workflow agents

Question

Foundry New endpoint protocol does not support workflow agents

BU XINZHE 0

Since today (May 22, 2026 JST), all our workflow-kind agents stopped

working across multiple regions, subscriptions, and projects.

When using the LEGACY endpoint:

/applications/{agent}/protocols/activityprotocol

→ Returns: "Error creating item on conversation"

with empty item_id and empty details (no actionable info)

When using the NEW endpoint (per agent-endpoints migration doc):

/agents/{agent}/endpoint/protocols/activityprotocol

Headers: Foundry-Features: AgentEndpoints=V1Preview

→ Returns clear error:

"Endpoint-scoped routes only support prompt and hosted agents.

Agent kind 'workflow' is not supported."

This appears to be a gap in the new endpoint rollout: workflow-kind

agents are not yet supported by the new endpoint-scoped routes,

while legacy routes seem to have been altered in a way that breaks

existing workflows.

Reproduced across:

2 regions (Japan East + another)
Multiple subscriptions
4 different workflows
Both new and legacy projects

Request ID (new endpoint): 3213fc3f0bb834c530a1cc2d1c898fc4

Sample legacy conversation_ids:

conv_2d587f8e4947326800z74C9yoarf0o39zbZT6lwa4DC9zsvxt5
conv_b5a06d602bd9747400Fdf7NC8iuNgkENzIJWv2XgHMVPXU9zH1

Reference doc:

[https://learn.microsoft.com/エージェントアプリケーションから新しいエージェントエンドポイントへの移行のURL]

Question:

Is workflow-kind support on the new endpoint coming soon, and is

the legacy endpoint breakage today expected or a regression?

This is currently blocking all workflow-based agent deployments

across our subscriptions.

Anshika Varshney 11,565 Reputation points Microsoft External Staff Moderator

2026-05-24T10:03:37.6266667+00:00
Hi BU XINZHE ,

Thanks for raising this. This issue with the new Foundry endpoint usually comes up when there is a mismatch between how the request is structured and what the new protocol expects.

what is happening

The new Foundry endpoint follows the updated OpenAI compatible API format. Some older parameters or patterns that worked before may not be supported in the new protocol.

So when you see errors like “not supported” or similar, it usually means:

The request is using an older format

Or a parameter is no longer valid in the new API

What you should check

Verify endpoint format

Make sure you are using the correct endpoint format for Foundry projects.

It should look like this:

project based endpoint

uses openai v1 path

If you are still using older Azure OpenAI style endpoints, that can cause issues.

Check request structure

The new API expects requests in standard OpenAI format.

Make sure:

messages array is used instead of older prompt format

roles like system, user are defined correctly

request body matches the expected schema

Old fields or custom fields may not be recognized.

Validate parameters

Some parameters have changed or are no longer supported.

For example:

older token parameters may be replaced with newer ones

certain options may not be supported in all models

If you are reusing older code, this is a common cause.

Check model compatibility

Not all models support all features.

Make sure:

the model you are using supports the features you are passing

advanced options are not used with unsupported models

Test with a minimal request

Try sending a very basic request first:

simple message only

no optional parameters

If that works, then gradually add parameters to see what is causing the issue.

Compare with working sample

Use a basic working example from documentation and compare with your request.

This helps identify:

missing fields

incorrect structure

unsupported parameters

This is not usually a runtime issue in your workflow. It is mostly due to differences between old and new API formats.

The new endpoint is stricter and expects requests to follow the updated schema.

Reference: You can review the official documentation here for correct request structure: https://learn.microsoft.com/azure/foundry

In short:

The new endpoint uses a different protocol

Older request formats may not work

Validate endpoint, request body, and parameters

Start with a minimal request and build up

I hope this helps. Do let me know if you have any further queries.

Thankyou!

2 answers

Your answer

Answer 1

Thanks for the AI summary. To confirm: this is being treated as a

service-side regression on the legacy workflow endpoints, since the

documented transition guarantees backward compatibility.

Could a moderator escalate to the Product Group? We do not have an

Azure support plan, and this is blocking workflow-based agents

across multiple subscriptions and regions in our organization.

Additional Request IDs and conversation_ids available on request.

Reproduction:

Multiple subscriptions, Japan East + another region
"Test in Playground" via workflow → fails instantly with "Error creating item on conversation"
New endpoint route (/agents/.../endpoint/...) → returns "Agent kind 'workflow' is not supported"

We would appreciate confirmation of whether:

(a) Engineering is aware of the regression

(b) Workflow-kind support on the new endpoint is on the roadmap

Answer 2

AI answer

Workflow-kind agents are currently not listed as supported on the new agent endpoint-scoped routes. The documented support on the new model explicitly calls out prompt and hosted agents as the primary agent types, and the migration guidance focuses on moving from legacy Agent Applications and project endpoints to the new stable agent endpoint for those agents.

From the migration documentation:

New agent endpoints (/agents/{agent}/endpoint/...) are the stable, consumer-facing endpoints tied to the new agent object model.
The new endpoint experience and features (traffic splitting, multiple protocols, enable/disable, A2A, direct publish to M365/Teams) are described in the context of the new agent types and do not mention workflow-kind agents.
Legacy Agent Applications and project endpoints continue to be supported during the transition period and are expected to keep working until an announced end-of-support date.

Given this, the behavior observed on the new endpoint (Agent kind 'workflow' is not supported.) is consistent with current documented capabilities: endpoint-scoped routes only support prompt and hosted agents at this time. The documentation does not state that workflow-kind agents are supported on the new endpoint, nor does it provide a timeline or commitment that workflow-kind support is “coming soon.”

Regarding the legacy endpoint behavior (“Error creating item on conversation” with empty details), the migration and FAQ documentation explicitly state that:

Legacy Agent Applications and legacy agents continue to work during the transition.
Agent Application deprecation and end-of-support are planned and will be announced, with a migration period.

There is no indication in the provided documentation that legacy workflow endpoints are expected to break at this time or that such a change is part of the planned migration steps. The described sudden failure across regions and subscriptions therefore aligns more with a regression or service-side incident than with an intentional, documented deprecation.

Based on the available documentation:

Workflow-kind agents are not currently supported on the new endpoint-scoped routes, and there is no published ETA or commitment in the docs for adding that support.
Legacy endpoints (including those used by workflow-based agents) are expected to remain functional during the transition and until an announced end-of-support date, so the breakage observed today is not described as expected behavior in the documentation and should be treated as a potential regression or service incident.

For a blocking, cross-region issue like this, the next step is to open an Azure support case with the request IDs and affected regions so the product group can investigate the regression on the legacy workflow endpoints.

References:

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Foundry New endpoint protocol does not support workflow agents

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