diff --git a/extensions/image-paste/index.ts b/extensions/image-paste/index.ts
index 214da4224..b04454fa1 100644
--- a/extensions/image-paste/index.ts
+++ b/extensions/image-paste/index.ts
@@ -531,6 +531,7 @@ export default function imagePaste(
   );
 
   pi.on("session_start", (_event, ctx) => {
+    attachments.clearDraft();
     installImagePasteEditor(pi, ctx, attachments);
   });
 
diff --git a/tests/extensions/image-paste/index.test.ts b/tests/extensions/image-paste/index.test.ts
index 8c509c8ac..1c19ba996 100644
--- a/tests/extensions/image-paste/index.test.ts
+++ b/tests/extensions/image-paste/index.test.ts
@@ -4,10 +4,15 @@ import { existsSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import test from "node:test";
-import type { KeybindingsManager } from "@earendil-works/pi-coding-agent";
+import type {
+  ExtensionAPI,
+  ExtensionContext,
+  KeybindingsManager,
+} from "@earendil-works/pi-coding-agent";
 import type { EditorComponent } from "@earendil-works/pi-tui";
 import {
   collapseClipboardPaths,
+  default as imagePaste,
   ImageAttachmentEditor,
   ImageAttachmentStore,
 } from "../../../extensions/image-paste/index.ts";
@@ -107,6 +112,27 @@ function harness() {
   return { store, base, editor, submitted };
 }
 
+test("new sessions do not retain prior image placeholder mappings", () => {
+  const store = new ImageAttachmentStore();
+  const path = temporaryImage("png", "previous-session");
+  store.attachClipboardPath(path, "");
+  const hooks = new Map<
+    string,
+    (event: unknown, ctx: ExtensionContext) => void
+  >();
+  const api = {
+    on(name: string, handler: (event: unknown, ctx: ExtensionContext) => void) {
+      hooks.set(name, handler);
+    },
+    registerMarkdownTransformer() {},
+  } as unknown as ExtensionAPI;
+
+  imagePaste(api, store);
+  hooks.get("session_start")?.({}, { mode: "rpc" } as ExtensionContext);
+
+  assert.equal(store.expandPlaceholders("[Image #1]"), "[Image #1]");
+});
+
 /**
  * Mirrors Pi's InteractiveMode.handleFollowUp(): it reads the text through
  * getExpandedText() *before* choosing a delivery path, and only the idle branch