diff --git a/apps/server/src/imageMime.test.ts b/apps/server/src/imageMime.test.ts
new file mode 100644
index 0000000000000000000000000000000000000000..a420e1f6b8bcf5d2e20f34a76f948ba5ce3ee0fb
--- /dev/null
+++ b/apps/server/src/imageMime.test.ts
@@ -0,0 +1,27 @@
+import { describe, expect, it } from "vitest";
+
+import { parseBase64DataUrl } from "./imageMime.ts";
+
+describe("imageMime", () => {
+  it("parses base64 data URL with mime type", () => {
+    expect(parseBase64DataUrl("data:image/png;base64,SGVsbG8=")).toEqual({
+      mimeType: "image/png",
+      base64: "SGVsbG8=",
+    });
+  });
+
+  it("parses base64 data URL with mime parameters", () => {
+    expect(parseBase64DataUrl("data:image/png;charset=utf-8;base64,SGVsbG8=")).toEqual({
+      mimeType: "image/png",
+      base64: "SGVsbG8=",
+    });
+  });
+
+  it("rejects non-base64 data URL", () => {
+    expect(parseBase64DataUrl("data:image/png;charset=utf-8,hello")).toBeNull();
+  });
+
+  it("rejects missing mime type", () => {
+    expect(parseBase64DataUrl("data:;base64,SGVsbG8=")).toBeNull();
+  });
+});
diff --git a/apps/server/src/imageMime.ts b/apps/server/src/imageMime.ts
index 249deff0ca8efb37a8708c6fbe3039a9aa3a2ca4..9ecf7615a6eed2fc8e88b17d7daab6023ff40df7 100644
--- a/apps/server/src/imageMime.ts
+++ b/apps/server/src/imageMime.ts
@@ -32,10 +32,22 @@ export const SAFE_IMAGE_FILE_EXTENSIONS = new Set([
 export function parseBase64DataUrl(
   dataUrl: string,
 ): { readonly mimeType: string; readonly base64: string } | null {
-  const match = /^data:([^;,]+);base64,([a-z0-9+/=\r\n]+)$/i.exec(dataUrl.trim());
+  const match = /^data:([^,]+),([a-z0-9+/=\r\n]+)$/i.exec(dataUrl.trim());
   if (!match) return null;
 
-  const mimeType = match[1]?.trim().toLowerCase();
+  const headerParts = (match[1] ?? "")
+    .split(";")
+    .map((part) => part.trim())
+    .filter((part) => part.length > 0);
+  if (headerParts.length < 2) {
+    return null;
+  }
+  const trailingToken = headerParts.at(-1)?.toLowerCase();
+  if (trailingToken !== "base64") {
+    return null;
+  }
+
+  const mimeType = headerParts[0]?.toLowerCase();
   const base64 = match[2]?.replace(/\s+/g, "");
   if (!mimeType || !base64) return null;
 
diff --git a/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts b/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
index 921f45b1631cbe03fcd6627691f9ecf9542dd76f..1b5271c51ac371058fd0ff29d2c0e6c102f9e62e 100644
--- a/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
+++ b/apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
@@ -421,7 +421,6 @@ const make = Effect.gen(function* () {
             { threadId: input.threadId, cwd, oldBranch, cause: Cause.pretty(cause) },
           ),
         ),
-        Effect.forkScoped,
       );
   });
 
@@ -464,7 +463,7 @@ const make = Effect.gen(function* () {
       messageId: message.id,
       messageText: message.text,
       ...(message.attachments !== undefined ? { attachments: branchGenerationAttachments } : {}),
-    });
+    }).pipe(Effect.forkScoped);
 
     yield* sendTurnForThread({
       threadId: event.payload.threadId,