diff --git a/src/features/agents/HomeEditor.tsx b/src/features/agents/HomeEditor.tsx
index 0d0b1392a..d7dfa29e9 100644
--- a/src/features/agents/HomeEditor.tsx
+++ b/src/features/agents/HomeEditor.tsx
@@ -5,10 +5,11 @@ import { executeAction } from "@/platform/actions";
 import { call, commands } from "@/platform/ipc";
 import { useTx, useTxTemplate } from "@/platform/i18n";
 import { basename, useProject } from "@/platform/project";
-import { Button, Icon, Select, T, type SelectOption } from "@/ui";
+import { Icon, Select, T, type SelectOption } from "@/ui";
 import { defaultTaskProject } from "./project";
 import { maybeEditorService } from "@/workbench/contributions";
 import { Composer } from "./Composer";
+import { SubmitButton } from "./SubmitButton";
 import { canSend, emptyDraft } from "./composerModel";
 import { ConfigPickers } from "./ConfigPickers";
 import { providerIcon } from "./model";
@@ -117,9 +118,12 @@ export function HomeEditor() {
             </>
           }
           actions={
-            <Button variant="primary" size="small" disabled={!canStart} onClick={start}>
-              {starting ? "Starting…" : "Start"}
-            </Button>
+            <SubmitButton
+              label={starting ? "Starting…" : "Start"}
+              pending={starting}
+              disabled={!canStart}
+              onClick={start}
+            />
           }
         />
         <div className={styles.where}>
diff --git a/src/features/agents/SessionEditor.tsx b/src/features/agents/SessionEditor.tsx
index a38f42834..7e756a179 100644
--- a/src/features/agents/SessionEditor.tsx
+++ b/src/features/agents/SessionEditor.tsx
@@ -27,6 +27,7 @@ import { useTx, tx } from "@/platform/i18n";
 import { isImeKey } from "@/platform/ime";
 import { TaskStatusIcon } from "./AgentsView";
 import { Composer } from "./Composer";
+import { SubmitButton } from "./SubmitButton";
 import { canSend, emptyDraft, retryParts, usageLabel, workTime } from "./composerModel";
 import { ConfigPickers } from "./ConfigPickers";
 import { findRanges, formatDuration, formatSentAt } from "./conversation";
@@ -891,15 +892,12 @@ function MessageEditor({
           <Button size="small" disabled={sending} onClick={onCancel}>
             Cancel
           </Button>
-          <Button
-            size="small"
-            variant="primary"
+          <SubmitButton
+            label="Send"
+            pending={sending}
             disabled={(!text.trim() && images.length === 0) || sending}
             onClick={() => void send()}
-          >
-            {sending && <Spinner size={12} />}
-            <T>Send</T>
-          </Button>
+          />
         </span>
       </div>
     </div>
@@ -1189,14 +1187,13 @@ function SessionComposer({
                 Stop
               </Button>
             )}
-            <Button
-              size="small"
+            <SubmitButton
+              label={busy ? "Queue" : "Send"}
+              pending={sending}
               variant={busy ? "secondary" : "primary"}
               disabled={!canSend(composer) || sending || task.status === "archived"}
               onClick={() => send(false)}
-            >
-              {busy ? "Queue" : "Send"}
-            </Button>
+            />
           </>
         }
       />
diff --git a/src/features/agents/SubmitButton.module.css b/src/features/agents/SubmitButton.module.css
new file mode 100644
index 000000000..be2574407
--- /dev/null
+++ b/src/features/agents/SubmitButton.module.css
@@ -0,0 +1,4 @@
+.submit {
+  width: var(--h-control);
+  padding: 0;
+}
diff --git a/src/features/agents/SubmitButton.tsx b/src/features/agents/SubmitButton.tsx
new file mode 100644
index 000000000..090b4e025
--- /dev/null
+++ b/src/features/agents/SubmitButton.tsx
@@ -0,0 +1,28 @@
+import { useTx } from "@/platform/i18n";
+import { Button, Icon, Spinner, tooltipAttrs, type ButtonProps } from "@/ui";
+import styles from "./SubmitButton.module.css";
+
+export function SubmitButton({
+  label,
+  pending = false,
+  variant = "primary",
+  ...props
+}: Pick<ButtonProps, "disabled" | "onClick" | "variant"> & {
+  label: "Start" | "Starting…" | "Send" | "Queue";
+  pending?: boolean;
+}) {
+  const tx = useTx();
+  const name = tx(label);
+  return (
+    <Button
+      {...props}
+      variant={variant}
+      size="small"
+      className={styles.submit}
+      aria-label={name}
+      {...tooltipAttrs(name)}
+    >
+      {pending ? <Spinner size={12} /> : <Icon name="arrow-up" size={14} />}
+    </Button>
+  );
+}
diff --git a/src/features/agents/composerCommands.test.tsx b/src/features/agents/composerCommands.test.tsx
index 41498a3f5..6558b5aec 100644
--- a/src/features/agents/composerCommands.test.tsx
+++ b/src/features/agents/composerCommands.test.tsx
@@ -1,5 +1,5 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
-import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
+import { act, fireEvent, render, screen, waitFor, within } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import type { AgentCommand, AgentProvider } from "@/bindings";
 
@@ -65,6 +65,28 @@ beforeEach(() => {
 });
 
 describe("New Task composer commands", () => {
+  it("names the icon-only Start action and disables it while starting", async () => {
+    agentCommands.mockResolvedValue({ status: "ok", data: [] });
+    let finish!: (value: unknown) => void;
+    agentCreate.mockReturnValue(new Promise((resolve) => (finish = resolve)));
+    render(<HomeEditor />);
+    const start = screen.getByRole("button", { name: "Start" });
+    expect(start.textContent).toBe("");
+    expect(start).toHaveAttribute("data-tooltip", "Start");
+    expect(start).toBeDisabled();
+    fireEvent.change(screen.getByRole("textbox"), { target: { value: "Do the task" } });
+    expect(start).toBeEnabled();
+    fireEvent.click(start);
+    const starting = screen.getByRole("button", { name: "Starting…" });
+    expect(starting).toBeDisabled();
+    expect(starting.textContent).toBe("");
+    expect(starting).toHaveAttribute("data-tooltip", "Starting…");
+    fireEvent.keyDown(screen.getByRole("textbox"), { key: "Enter" });
+    expect(agentCreate).toHaveBeenCalledTimes(1);
+    await act(async () => finish({ status: "error", error: { kind: "invalid", message: "stop here" } }));
+    expect(screen.getByRole("button", { name: "Start" })).toBeEnabled();
+  });
+
   it("completes the project's skills merged with the agent's commands", async () => {
     agentCommands.mockResolvedValue({
       status: "ok",
diff --git a/src/features/agents/messageEditing.test.tsx b/src/features/agents/messageEditing.test.tsx
index efe5ba32e..4542fa063 100644
--- a/src/features/agents/messageEditing.test.tsx
+++ b/src/features/agents/messageEditing.test.tsx
@@ -119,6 +119,15 @@ describe("a sent message with images", () => {
 });
 
 describe("editing a sent agent message", () => {
+  it("names the icon-only edit-and-resend action and disables empty edits", async () => {
+    const { box, send } = await edit();
+    expect(send.textContent).toBe("");
+    expect(send).toHaveAttribute("data-tooltip", "Send");
+    expect(send).toBeEnabled();
+    fireEvent.change(box, { target: { value: "" } });
+    expect(send).toBeDisabled();
+  });
+
   it("keeps Enter, Shift+Enter and IME confirmation for editing", async () => {
     const { box } = await edit();
     fireEvent.keyDown(box, { key: "Enter" });
@@ -156,6 +165,9 @@ describe("editing a sent agent message", () => {
     expect(ipc.rollback).toHaveBeenCalledWith(task.id, 0);
     expect(ipc.prompt).not.toHaveBeenCalled();
     expect(send).toBeDisabled();
+    expect(send).toHaveAccessibleName("Send");
+    expect(send.textContent).toBe("");
+    expect(send.querySelector('[role="status"]')).toBeInTheDocument();
     fireEvent.keyDown(box, { key: "Enter", metaKey: true });
     expect(ipc.rollback).toHaveBeenCalledTimes(1);
     await act(async () => finish({ status: "ok", data: null }));
@@ -223,3 +235,35 @@ describe("editing a sent agent message", () => {
     },
   );
 });
+
+describe("session composer submission", () => {
+  it.each(["click", "Enter"])("keeps an accessible icon-only Send action with %s submission", async (method) => {
+    let finish!: (value: unknown) => void;
+    ipc.prompt.mockReturnValue(new Promise((resolve) => (finish = resolve)));
+    render(<SessionEditor input={{ kind: "agent-session", key: task.id, data: { task: task.id } }} />);
+    const send = screen.getByRole("button", { name: "Send" });
+    expect(send.textContent).toBe("");
+    expect(send).toHaveAttribute("data-tooltip", "Send");
+    expect(send).toBeDisabled();
+    const box = screen.getByRole("textbox", { name: "Message" });
+    fireEvent.change(box, { target: { value: "Follow up" } });
+    expect(send).toBeEnabled();
+    if (method === "click") fireEvent.click(send);
+    else fireEvent.keyDown(box, { key: "Enter" });
+    expect(ipc.prompt).toHaveBeenCalledExactlyOnceWith(task.id, { text: "Follow up", files: [], images: [] }, false);
+    expect(send).toBeDisabled();
+    await act(async () => finish({ status: "ok", data: null }));
+    expect(box).toHaveValue("");
+  });
+
+  it("keeps Queue named and leaves Stop unchanged while the agent works", async () => {
+    useAgents.setState({ tasks: new Map([[task.id, { ...task, status: "running" }]]) });
+    render(<SessionEditor input={{ kind: "agent-session", key: task.id, data: { task: task.id } }} />);
+    const queue = screen.getByRole("button", { name: "Queue" });
+    expect(queue.textContent).toBe("");
+    expect(queue).toHaveAttribute("data-tooltip", "Queue");
+    expect(queue).toBeDisabled();
+    expect(screen.getAllByRole("button", { name: "Stop" }).some((button) => button.textContent === "Stop")).toBe(true);
+    await screen.findByText("Original message");
+  });
+});