diff --git a/CHANGELOG.md b/CHANGELOG.md
index e6e3c0931..1c6169fda 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -113,6 +113,14 @@ The tools run in the browser as the signed-in person, over the same `POST /api/p
 person uses, so who may take a slug is answered the same way and the `configuration.changed` audit
 row is written the same way.
 
+### Resetting a computer clears the activity pane
+
+Resetting a Bot's computer deletes the browser profile it worked on, but the activity pane beside the
+chat went on listing the commands and file operations that ran there. They sat alongside anything the
+Bot did afterwards with nothing to tell the two apart, and only reloading the page cleared them. The
+pane now forgets a Bot's history when that Bot's computer is reset. Stopping a browser is unchanged:
+the profile survives a stop and is meant to resume, so what it did is still true of the machine.
+
 ### A person can set standing instructions that every coworker follows
 
 Settings now has a box for standing instructions: one piece of text per person, saved once and
diff --git a/app/src/lib/computers/mutations.ts b/app/src/lib/computers/mutations.ts
index 8fa014bec..a4c1e8f43 100644
--- a/app/src/lib/computers/mutations.ts
+++ b/app/src/lib/computers/mutations.ts
@@ -1,5 +1,6 @@
 import { mutationOptions, type QueryClient } from "@tanstack/react-query";
 import { client } from "@/lib/client";
+import { clearActivity } from "./activity";
 import { type ActionPolicy, computerKeys } from "./queries";
 
 /** Stopping frees the container; resetting also deletes the browser profile. */
@@ -23,7 +24,11 @@ export function setComputerStateMutationOptions(queryClient: QueryClient) {
         },
       );
     },
-    onSuccess: () => invalidateComputers(queryClient),
+    /** A reset deletes the profile those commands ran on; a stop keeps it, so only reset forgets. */
+    onSuccess: (_result, variables) => {
+      if (variables.action === "reset") clearActivity(variables.botId);
+      return invalidateComputers(queryClient);
+    },
   });
 }
 
diff --git a/app/tests/computer-reset-clears-activity.test.ts b/app/tests/computer-reset-clears-activity.test.ts
new file mode 100644
index 000000000..53e2be294
--- /dev/null
+++ b/app/tests/computer-reset-clears-activity.test.ts
@@ -0,0 +1,74 @@
+import { afterEach, beforeEach, expect, test } from "bun:test";
+import type { QueryClient } from "@tanstack/react-query";
+import {
+  activityFor,
+  clearActivity,
+  recordActivity,
+} from "../src/lib/computers/activity";
+import { setComputerStateMutationOptions } from "../src/lib/computers/mutations";
+
+const realFetch = globalThis.fetch;
+
+const queryClient = {
+  invalidateQueries: async () => undefined,
+} as unknown as QueryClient;
+
+beforeEach(() => {
+  globalThis.fetch = (async () =>
+    new Response(null, { status: 200 })) as unknown as typeof fetch;
+  clearActivity("general-assistant");
+  recordActivity("general-assistant", {
+    kind: "command",
+    subject: "echo repro-marker-bravo",
+    output: "repro-marker-bravo\n",
+    exitCode: 0,
+  });
+});
+
+afterEach(() => {
+  globalThis.fetch = realFetch;
+  clearActivity("general-assistant");
+});
+
+async function run(action: "stop" | "reset") {
+  const options = setComputerStateMutationOptions(queryClient);
+  const variables = { action, botId: "general-assistant" } as const;
+  await options.mutationFn?.(variables);
+  await options.onSuccess?.(
+    undefined as never,
+    variables,
+    undefined as never,
+    undefined as never,
+  );
+}
+
+test("resetting a computer forgets what the Bot did on the profile it deleted", async () => {
+  expect(activityFor("general-assistant")).toHaveLength(1);
+
+  await run("reset");
+
+  expect(activityFor("general-assistant")).toEqual([]);
+});
+
+test("stopping a browser keeps the history, because the profile survives it", async () => {
+  await run("stop");
+
+  expect(activityFor("general-assistant")).toHaveLength(1);
+  expect(activityFor("general-assistant")[0]?.subject).toBe(
+    "echo repro-marker-bravo",
+  );
+});
+
+test("one Bot's reset leaves another Bot's history alone", async () => {
+  recordActivity("knowledge", {
+    kind: "list_files",
+    subject: "the workspace",
+    output: "notes.md\n",
+  });
+
+  await run("reset");
+
+  expect(activityFor("general-assistant")).toEqual([]);
+  expect(activityFor("knowledge")).toHaveLength(1);
+  clearActivity("knowledge");
+});