fix(hook): fix UserPromptSubmit payload to capture input text instead of empty string

CHANGELOG.md

@@ -11,6 +11,8 @@ Only write entries that are worth mentioning to users.
 
 ## Unreleased
 
+- Core: Fix `UserPromptSubmit` hook receiving empty prompt text for non-string user input — content part lists (images, attachments) now have their text extracted via `Message.extract_text` instead of being replaced with `""`
+
 ## 1.44.0 (2026-05-13)
 
 - Shell: Add slash command alias resolution — aliases such as `/h`, `?`, and `status` now resolve to their canonical commands (`/help`, `/usage`); the completer and help output display alias matches as `/name (alias)` for clarity

docs/en/release-notes/changelog.md

@@ -4,6 +4,8 @@ This page documents the changes in each Kimi Code CLI release.
 
 ## Unreleased
 
+- Core: Fix `UserPromptSubmit` hook receiving empty prompt text for non-string user input — content part lists (images, attachments) now have their text extracted via `Message.extract_text` instead of being replaced with `""`
+
 ## 1.44.0 (2026-05-13)
 
 - Shell: Add slash command alias resolution — aliases such as `/h`, `?`, and `status` now resolve to their canonical commands (`/help`, `/usage`); the completer and help output display alias matches as `/name (alias)` for clarity

docs/zh/release-notes/changelog.md

@@ -4,6 +4,8 @@
 
 ## 未发布
 
+- Core：修复 `UserPromptSubmit` hook 在用户输入为非字符串内容时收到空 prompt 文本的问题——包含图片、附件等 ContentPart 列表的输入现在通过 `Message.extract_text` 提取可读文本，而非被替换为空字符串
+
 ## 1.44.0 (2026-05-13)
 
 - Shell：新增斜杠命令别名解析——别名（如 `/h`、`?`、`status`）现在能正确解析到对应的正式命令（`/help`、`/usage`）；补全器和帮助输出会将别名匹配项显示为 `/name (alias)`，方便识别

src/kimi_cli/soul/kimisoul.py

@@ -605,7 +605,11 @@ async def run(
             # they are not user input, and a user-configured prompt-blocking
             # hook would drop the notification and hang the wait loop.
             if not skip_user_prompt_hook:
-                text_input_for_hook = user_input if isinstance(user_input, str) else ""
+                if isinstance(user_input, str):
+                    text_input_for_hook = user_input
+                else:
+                    user_message = Message(role="user", content=user_input)
+                    text_input_for_hook = user_message.extract_text(" ").strip()
 
                 hook_results = await self._hook_engine.trigger(
                     "UserPromptSubmit",

tests/core/test_kimisoul_hooks.py

@@ -0,0 +1,50 @@
+"""Tests for KimiSoul lifecycle hook integration."""
+
+from __future__ import annotations
+
+from pathlib import Path
+from unittest.mock import AsyncMock
+
+import pytest
+
+import kimi_cli.soul.kimisoul as kimisoul_module
+from kosong.tooling.empty import EmptyToolset
+
+from kimi_cli.hooks.config import HookDef
+from kimi_cli.hooks.engine import HookEngine
+from kimi_cli.soul.agent import Agent, Runtime
+from kimi_cli.soul.context import Context
+from kimi_cli.soul.kimisoul import KimiSoul
+from kimi_cli.wire.types import TextPart
+
+
+@pytest.mark.asyncio
+async def test_user_prompt_submit_extracts_text_from_content_parts(
+    runtime: Runtime, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """UserPromptSubmit hook receives extracted text when input is list[ContentPart]."""
+    captured_payloads: list[dict] = []
+
+    async def _capture_trigger(event: str, *, matcher_value: str = "", input_data: dict | None = None) -> list:
+        captured_payloads.append(input_data or {})
+        return []
+
+    agent = Agent(
+        name="Test Agent",
+        system_prompt="Test system prompt.",
+        toolset=EmptyToolset(),
+        runtime=runtime,
+    )
+    soul = KimiSoul(agent, context=Context(file_backend=tmp_path / "history.jsonl"))
+    soul._turn = AsyncMock(return_value=None)  # type: ignore[method-assign]
+    monkeypatch.setattr(kimisoul_module, "wire_send", lambda _msg: None)
+
+    hook_engine = HookEngine([HookDef(event="UserPromptSubmit", command="echo ok", timeout=5)])
+    monkeypatch.setattr(hook_engine, "trigger", _capture_trigger)
+    soul.set_hook_engine(hook_engine)
+
+    await soul.run([TextPart(text="hello world")])
+
+    user_prompt_payloads = [p for p in captured_payloads if p.get("hook_event_name") == "UserPromptSubmit"]
+    assert len(user_prompt_payloads) == 1
+    assert user_prompt_payloads[0].get("prompt") == "hello world"