[Bug] ReActAgent.stopAction() does not properly handle LLM output schema issue

[Ljj09082]

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Description

ReActAgent.stopAction()output = mapper.readValue(String.valueOf(output), (Class<?>) outputSchema);

Caused by: java.lang.RuntimeException: org.apache.flink.shaded.jackson2.com.fasterxml.jackson.core.JsonParseException: Unexpected character ('' (code 96)): expected a valid value (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
at [Source: (String)"json { "id": "B0092UF54A", "score": 5, "reasons": [] } "; line: 1, column: 2]parse error```json
{
"id": "B0092UF54A",
"score": 5,
"reasons": []
}

	at org.apache.flink.agents.api.agents.ReActAgent.stopAction(ReActAgent.java:193)
	... 24 more`

### How to reproduce

run ReActAgentExample； custom model deepseek-chat

### Version and environment

main
java
macOS
local Test
flink-1.20.3

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

[wenjin272]

Hi, @Ljj09082, thank you for reporting this 'bug'.

In road map, flink-agents should provide error handling strategy configuration to decide whether to fail the flink job or just log and skip the unexpected llm response. I have add TODO in the code but not crated the correspond issue.

flink-agents/api/src/main/java/org/apache/flink/agents/api/agents/ReActAgent.java

Line 186 in 1260bf0

// TODO: handle parse error according to configured strategy.

So this issue is more like a tech debt.

Would you be willing to add the error handling configuration and fix this issue? Also, could you please format the title and describe in English?

[twosom]

can you using english please?
Thank you