diff --git a/server-rs/crates/api-server/src/editor_project_icon.rs b/server-rs/crates/api-server/src/editor_project_icon.rs
index 67989ef1f..80a19e7e5 100644
--- a/server-rs/crates/api-server/src/editor_project_icon.rs
+++ b/server-rs/crates/api-server/src/editor_project_icon.rs
@@ -664,33 +664,22 @@ async fn run_icon_spec_extra_param_llm(
 
     for attempt in 1..=ICON_SPEC_LLM_MAX_ATTEMPTS {
         match llm_client.run(request.clone()).await {
-            Ok(response) => {
-                let text = response.text.trim();
-                if text.is_empty() {
-                    if attempt == ICON_SPEC_LLM_MAX_ATTEMPTS {
-                        return Err(AppError::from_status(StatusCode::BAD_GATEWAY).with_details(
-                            json!({
-                                "provider": "editor-icon-spec-llm",
-                                "operation": "complete-extra-param",
-                                "message": "LLM 未返回可用文本",
-                            }),
-                        ));
-                    }
-                } else {
-                    match parse_extra_param(text) {
-                        Ok(extra_param) => return Ok(extra_param),
-                        Err(_) if attempt < ICON_SPEC_LLM_MAX_ATTEMPTS => {}
-                        Err(_) => {
-                            return Err(AppError::from_status(StatusCode::BAD_GATEWAY)
-                                .with_details(json!({
-                                    "provider": "editor-icon-spec-llm",
-                                    "operation": "complete-extra-param",
-                                    "message": "LLM 返回内容不符合图标规范参数契约",
-                                })));
-                        }
-                    }
+            Ok(response) => match parse_extra_param_response(
+                response.text.as_str(),
+                response.finish_reason.as_deref(),
+            ) {
+                Ok(extra_param) => return Ok(extra_param),
+                Err(_) if attempt < ICON_SPEC_LLM_MAX_ATTEMPTS => {}
+                Err(error) => {
+                    return Err(AppError::from_status(StatusCode::BAD_GATEWAY).with_details(
+                        json!({
+                            "provider": "editor-icon-spec-llm",
+                            "operation": "complete-extra-param",
+                            "message": error.message(),
+                        }),
+                    ));
                 }
-            }
+            },
             Err(error) if is_retryable_llm_error(&error) => {
                 if attempt == ICON_SPEC_LLM_MAX_ATTEMPTS {
                     return Err(map_llm_error(error));
@@ -703,6 +692,39 @@ async fn run_icon_spec_extra_param_llm(
     unreachable!("icon spec extra param retry loop always returns")
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum ExtraParamResponseError {
+    Empty,
+    Incomplete,
+    Invalid,
+}
+
+impl ExtraParamResponseError {
+    fn message(self) -> &'static str {
+        match self {
+            Self::Empty => "LLM 未返回可用文本",
+            Self::Incomplete => "LLM 返回内容未完整结束",
+            Self::Invalid => "LLM 返回内容不符合图标规范参数契约",
+        }
+    }
+}
+
+fn parse_extra_param_response(
+    text: &str,
+    finish_reason: Option<&str>,
+) -> Result<ExtraParam, ExtraParamResponseError> {
+    if finish_reason.is_some_and(|reason| {
+        platform_llm::is_incomplete_finish_reason(platform_llm::LlmApiKind::OpenAiChat, reason)
+    }) {
+        return Err(ExtraParamResponseError::Incomplete);
+    }
+    let text = text.trim();
+    if text.is_empty() {
+        return Err(ExtraParamResponseError::Empty);
+    }
+    parse_extra_param(text).map_err(|_| ExtraParamResponseError::Invalid)
+}
+
 fn parse_extra_param(text: &str) -> Result<ExtraParam, ()> {
     let mut extra_param = serde_json::from_str::<ExtraParam>(text).map_err(|_| ())?;
     for value in [
@@ -2752,6 +2774,20 @@ mod tests {
         assert!(parse_extra_param(oversized.to_string().as_str()).is_err());
     }
 
+    #[test]
+    fn extra_param_rejects_explicitly_incomplete_llm_responses() {
+        let complete_json =
+            r#"{"genre":"策略","theme":"现代军事","useCase":"PC","targetUser":"策略游戏玩家"}"#;
+
+        for finish_reason in ["length", "content_filter"] {
+            assert_eq!(
+                parse_extra_param_response(complete_json, Some(finish_reason)),
+                Err(ExtraParamResponseError::Incomplete)
+            );
+        }
+        assert!(parse_extra_param_response(complete_json, Some("stop")).is_ok());
+    }
+
     #[test]
     fn icon_spec_generation_text_enforces_prompt_max_length() {
         assert!(