Help: What is the standard way to handle function call failure

[oracle-fusion-middleware-team]

Self Checks

• I have searched for existing issues search for existing issues, including closed ones.
• I confirm that I am using English to submit this report (我已阅读并同意 Language Policy).
• [FOR CHINESE USERS] 请务必使用英文提交 Issue，否则会被关闭。谢谢！:)
• Please do not modify this template :) and fill in all the required fields.

1. Is this request related to a challenge you're experiencing? Tell me about your story.

In Function Call node (agent strategy), what if the call fails due to lack of parameter? How could I mention the required parameters to the user in the response, so that they can try again (maybe iterate multiple times)?
I'm using a Chatflow. Is there a standard pattern to do this?

2. Additional context or comments

No response

[dosubot[bot]]

Hi @oracle-fusion-middleware-team! I'm Dosu and I’m helping the dify team.

Dify's Function Call node (agent strategy) handles missing parameters by raising a structured error (like ToolParameterError) when a required parameter isn't provided. This error is reported up the workflow and can be surfaced to the user with a clear message about which parameter is missing. The standard pattern is to catch this error, inform the user about the missing parameter(s), and prompt them to provide the required information so the function call can be retried—enabling an iterative, conversational flow in Chatflow. This approach aligns with best practices for LLM-based agent workflows, where users are re-prompted for missing details and can try again until all required parameters are provided. You can see this error handling and user feedback mechanism in the ToolNode implementation and related workflow orchestration logic in Dify’s codebase (source).

To reply, just mention @dosu.

---

^{How did I do? Good | Irrelevant | Incorrect | Verbose | Hallucination | Report 🐛 | Other}