OpenAI Realtime API MCP tool calls not executing with Azure deployment

What this error means

Realtime does not execute tool calls with mcp — MCP server connected but tool calls silently never fire, only instruction text returned is a OpenAI API failure pattern reported for developers trying to fix openai realtime api mcp integration: tool calls never execute despite mcp server being connected and verified with inspector. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub issue openai/openai-python#3128 (Apr 2026, bug-labeled): OpenAI Realtime SIP app connected to Twilio with MCP server (Langflow). MCP verified working with @modelcontextprotocol/inspector. Tool calls never fire — app only returns instruction text. Affects Azure OpenAI Realtime endpoint. Category mapping: OpenAI API (API feature failure).

Common causes

• GitHub issue openai/openai-python#3128 (Apr 2026, bug-labeled): OpenAI Realtime SIP app connected to Twilio with MCP server (Langflow). MCP verified working with @modelcontextprotocol/inspector. Tool calls never fire — app only returns instruction text. Affects Azure OpenAI Realtime endpoint. Category mapping: OpenAI API (API feature failure).

Quick fixes

1. Confirm the exact error signature matches Realtime does not execute tool calls with mcp — MCP server connected but tool calls silently never fire, only instruction text returned.
2. Check the OpenAI API account, local tool state, and provider configuration involved in the failing workflow.
3. Check the build output, project root, and deployment platform configuration before redeploying.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/openai/openai-python/issues/3128

Evidence note: GitHub issue openai/openai-python#3128 (Apr 2026, bug-labeled): OpenAI Realtime SIP app connected to Twilio with MCP server (Langflow). MCP verified working with @modelcontextprotocol/inspector. Tool calls never fire — app only returns instruction text. Affects Azure OpenAI Realtime endpoint. Category mapping: OpenAI API (API feature failure).

Related errors

• OpenAI API

FAQ

What should I check first?

Start with the exact Realtime does not execute tool calls with mcp — MCP server connected but tool calls silently never fire, only instruction text returned text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed OpenAI API workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without Realtime does not execute tool calls with mcp — MCP server connected but tool calls silently never fire, only instruction text returned.