GPT-5-nano with mcp tools. It was possible few days ago. Why isn't possible anymore ?

[GGA-PERSO]

Does this occur consistently?
Repro steps:

Action: AgentDesignerWebview.deployAgent
Error type: HTTPError
Error Message: 400: The model 'gpt-5-nano' cannot be used with the following tools: mcp. This model only supports Responses API compatible tools.

Version: 0.17.0
OS: win32
OS Arch: x64
OS Release: 10.0.26100
Product: Visual Studio Code
Product Version: 1.109.5
Language: en
UTC time: Wed, 25 Feb 2026 09:08:47 GMT

Call Stack

AIFServiceClient.handleResponse extension.js:160138:19
AIFServiceClient.createAgent extension.js:160681:29
extension.js:183739:20extension.js:183739:20

[github-actions]

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