fix(compaction): filter media parts to prevent API error

CHANGELOG.md

@@ -11,6 +11,7 @@ Only write entries that are worth mentioning to users.
 
 ## Unreleased
 
+- Core: Fix context compaction failing when conversation contains media parts (images, audio, video) — switch from blacklist filtering (exclude `ThinkPart`) to whitelist filtering (only keep `TextPart`) to prevent unsupported content types from being sent to the compaction API
 - Web: Fix `@` file mention index not refreshing after switching sessions or when workspace files change — reset index on session switch, auto-refresh after 30s staleness, and support path-prefix search beyond the 500-file limit
 
 ## 1.19.0 (2026-03-10)

docs/en/release-notes/changelog.md

@@ -4,6 +4,7 @@ This page documents the changes in each Kimi Code CLI release.
 
 ## Unreleased
 
+- Core: Fix context compaction failing when conversation contains media parts (images, audio, video) — switch from blacklist filtering (exclude `ThinkPart`) to whitelist filtering (only keep `TextPart`) to prevent unsupported content types from being sent to the compaction API
 - Web: Fix `@` file mention index not refreshing after switching sessions or when workspace files change — reset index on session switch, auto-refresh after 30s staleness, and support path-prefix search beyond the 500-file limit
 
 ## 1.19.0 (2026-03-10)

docs/zh/release-notes/changelog.md

@@ -4,6 +4,7 @@
 
 ## 未发布
 
+- Core：修复对话包含媒体内容（图片、音频、视频）时上下文压缩失败的问题——将过滤策略从黑名单（排除 `ThinkPart`）改为白名单（仅保留 `TextPart`），防止不支持的内容类型被发送到压缩 API
 - Web：修复 `@` 文件提及索引在切换会话或工作区文件变更后不刷新的问题——切换会话时重置索引，30 秒过期自动刷新，输入路径前缀可查找超出 500 文件上限的文件
 
 ## 1.19.0 (2026-03-10)

src/kimi_cli/soul/compaction.py

@@ -175,7 +175,7 @@ def prepare(
                 TextPart(text=f"## Message {i + 1}\nRole: {msg.role}\nContent:\n")
             )
             compact_message.content.extend(
-                part for part in msg.content if not isinstance(part, ThinkPart)
+                part for part in msg.content if isinstance(part, TextPart)
             )
         prompt_text = "\n" + prompts.COMPACT
         if custom_instruction:

tests/core/test_simple_compaction.py

@@ -2,7 +2,7 @@
 
 from inline_snapshot import snapshot
 from kosong.chat_provider import TokenUsage
-from kosong.message import Message
+from kosong.message import AudioURLPart, ImageURLPart, Message, VideoURLPart
 
 import kimi_cli.prompts as prompts
 from kimi_cli.soul.compaction import CompactionResult, SimpleCompaction, should_auto_compact
@@ -213,3 +213,64 @@ def test_custom_ratio_triggers_earlier(self):
     def test_zero_tokens_never_triggers(self):
         """Empty context should never trigger compaction."""
         assert not should_auto_compact(0, 200_000, trigger_ratio=0.85, reserved_context_size=50_000)
+
+
+def test_prepare_only_keeps_text_parts_in_compaction():
+    """Compaction input should only contain TextPart (whitelist approach).
+
+    Non-text parts (media, think, etc.) are filtered out because the compaction
+    API endpoint only supports text content.
+
+    Fixes: https://github.com/MoonshotAI/kimi-cli/issues/1395
+    Fixes: https://github.com/MoonshotAI/kimi-cli/issues/1390
+    """
+    messages = [
+        Message(
+            role="user",
+            content=[
+                TextPart(text="Analyze these files:"),
+                ImageURLPart(image_url=ImageURLPart.ImageURL(url="data:image/png;base64,IMG")),
+                AudioURLPart(audio_url=AudioURLPart.AudioURL(url="data:audio/mp3;base64,AUD")),
+                VideoURLPart(video_url=VideoURLPart.VideoURL(url="data:video/mp4;base64,VID")),
+                ThinkPart(think="internal reasoning"),
+            ],
+        ),
+        Message(role="assistant", content=[TextPart(text="I can see all the media files.")]),
+        Message(role="user", content=[TextPart(text="What's your conclusion?")]),
+    ]
+
+    result = SimpleCompaction(max_preserved_messages=1).prepare(messages)
+
+    assert result.compact_message is not None
+    # Verify only TextPart remains in the compaction request
+    for part in result.compact_message.content:
+        assert isinstance(part, TextPart), (
+            f"Only TextPart should be in compaction input, got {type(part).__name__}"
+        )
+
+    # Text content should be preserved
+    texts = [p.text for p in result.compact_message.content if isinstance(p, TextPart)]
+    assert any("Analyze these files:" in t for t in texts)
+    assert any("I can see all the media files." in t for t in texts)
+
+
+def test_prepare_preserves_media_parts_in_recent_messages():
+    """Media parts in preserved (recent) messages should remain untouched."""
+    messages = [
+        Message(role="user", content=[TextPart(text="Old question")]),
+        Message(role="assistant", content=[TextPart(text="Old answer")]),
+        Message(
+            role="user",
+            content=[
+                TextPart(text="Look at this video:"),
+                VideoURLPart(video_url=VideoURLPart.VideoURL(url="data:video/mp4;base64,VID")),
+            ],
+        ),
+        Message(role="assistant", content=[TextPart(text="Nice video!")]),
+    ]
+
+    result = SimpleCompaction(max_preserved_messages=2).prepare(messages)
+
+    # Preserved messages should keep their media parts intact
+    preserved_user_msg = result.to_preserve[0]
+    assert any(isinstance(p, VideoURLPart) for p in preserved_user_msg.content)