diff --git a/.changeset/kosong-provider-conversion-fixes.md b/.changeset/kosong-provider-conversion-fixes.md
new file mode 100644
index 000000000..0fdb9d2fe
--- /dev/null
+++ b/.changeset/kosong-provider-conversion-fixes.md
@@ -0,0 +1,6 @@
+---
+"@moonshot-ai/kimi-code": patch
+"@moonshot-ai/kimi-code-sdk": patch
+---
+
+Fix two provider message-conversion bugs: the OpenAI Responses provider no longer drops encrypted reasoning on non-streaming responses whose reasoning item has an empty summary (it now round-trips `encrypted_content` like the streaming path), and the Google GenAI provider now keeps the explicit MIME type of a data URL that has no `;base64` parameter instead of falling back to a generic type.
diff --git a/packages/kosong/src/providers/google-genai.ts b/packages/kosong/src/providers/google-genai.ts
index 1feadb639..eb63bd32c 100644
--- a/packages/kosong/src/providers/google-genai.ts
+++ b/packages/kosong/src/providers/google-genai.ts
@@ -169,9 +169,14 @@ function convertMediaUrl(
     const data = url.slice(commaIndex + 1);
     const colonIndex = meta.indexOf(':');
     const semiIndex = meta.indexOf(';');
+    // A data URL may carry an explicit MIME type without a `;base64`
+    // parameter (e.g. `data:image/png,<raw>`), so end the MIME slice at the
+    // first `;` when present, otherwise at the end of the meta segment —
+    // requiring only the leading `:` and a non-empty type.
+    const mimeEnd = semiIndex !== -1 ? semiIndex : meta.length;
     const mimeType =
-      colonIndex !== -1 && semiIndex !== -1
-        ? meta.slice(colonIndex + 1, semiIndex)
+      colonIndex !== -1 && mimeEnd > colonIndex + 1
+        ? meta.slice(colonIndex + 1, mimeEnd)
         : fallbackMimeType;
     return { inlineData: { mimeType, data } };
   }
diff --git a/packages/kosong/src/providers/openai-responses.ts b/packages/kosong/src/providers/openai-responses.ts
index 3595e2105..e1054f392 100644
--- a/packages/kosong/src/providers/openai-responses.ts
+++ b/packages/kosong/src/providers/openai-responses.ts
@@ -734,6 +734,19 @@ export class OpenAIResponsesStreamedMessage implements StreamedMessage {
           }
           yield thinkPart;
         }
+        // Mirror the streaming `output_item.done` path: when there is no
+        // summary text but the item still carries encrypted reasoning, emit a
+        // single empty think part so the encrypted content the provider asked
+        // for (`include: reasoning.encrypted_content`) survives round-tripping
+        // into the next turn instead of being silently dropped.
+        if (outputItem.summary.length === 0 && outputItem.encryptedContent !== undefined) {
+          const thinkPart: StreamedMessagePart & { encrypted: string } = {
+            type: 'think',
+            think: '',
+            encrypted: outputItem.encryptedContent,
+          };
+          yield thinkPart;
+        }
       }
     }
   }
diff --git a/packages/kosong/test/google-genai.test.ts b/packages/kosong/test/google-genai.test.ts
index 61c51f42c..439758668 100644
--- a/packages/kosong/test/google-genai.test.ts
+++ b/packages/kosong/test/google-genai.test.ts
@@ -410,6 +410,27 @@ describe('GoogleGenAIChatProvider', () => {
       });
     });
 
+    it('keeps the explicit MIME type of a data URL that has no ;base64 parameter', () => {
+      const messages: Message[] = [
+        {
+          role: 'user',
+          content: [{ type: 'image_url', imageUrl: { url: 'data:image/png,RAWDATA' } }],
+          toolCalls: [],
+        },
+      ];
+
+      const contents = messagesToGoogleGenAIContents(messages);
+      const userContent = contents[0] as unknown as { parts: Array<Record<string, unknown>> };
+      const inlineData = userContent.parts.find((p) => 'inlineData' in p) as
+        | { inlineData: { mimeType: string; data: string } }
+        | undefined;
+      // Without the fix the MIME slice required a ';', so this fell back to the
+      // generic fallback type instead of the URL's own `image/png`.
+      expect(inlineData).toMatchObject({
+        inlineData: { mimeType: 'image/png', data: 'RAWDATA' },
+      });
+    });
+
     it('tool message with audio_url and video_url results yields independent parts', () => {
       const messages: Message[] = [
         {
diff --git a/packages/kosong/test/openai-responses.test.ts b/packages/kosong/test/openai-responses.test.ts
index 5946b6309..ac6bedd18 100644
--- a/packages/kosong/test/openai-responses.test.ts
+++ b/packages/kosong/test/openai-responses.test.ts
@@ -1192,6 +1192,31 @@ describe('OpenAIResponsesChatProvider', () => {
 
       expect(parts).toEqual([{ type: 'think', think: 'Thinking...' }]);
     });
+
+    it('non-stream reasoning with empty summary still preserves encrypted_content', async () => {
+      // Matches the streaming output_item.done path: an encrypted reasoning
+      // item with no summary text must still emit a think part carrying the
+      // encrypted content, so it survives round-tripping into the next turn.
+      const provider = createProvider();
+      (provider as any)._stream = false;
+      ((provider as any)._client.responses as unknown as Record<string, unknown>)['create'] = vi
+        .fn()
+        .mockResolvedValue({
+          id: 'resp_reason3',
+          output: [{ type: 'reasoning', encrypted_content: 'enc_empty_summary', summary: [] }],
+          usage: { input_tokens: 1, output_tokens: 1, total_tokens: 2 },
+        });
+
+      const stream = await provider.generate(
+        '',
+        [],
+        [{ role: 'user', content: [{ type: 'text', text: 'Hi' }], toolCalls: [] }],
+      );
+      const parts: StreamedMessagePart[] = [];
+      for await (const p of stream) parts.push(p);
+
+      expect(parts).toEqual([{ type: 'think', think: '', encrypted: 'enc_empty_summary' }]);
+    });
   });
 
   describe('provider property accessors', () => {