diff --git a/desktop/src/features/agents/ui/AgentSessionToolItem/CompactMessageSummary.tsx b/desktop/src/features/agents/ui/AgentSessionToolItem/CompactMessageSummary.tsx
index 89aeba920e..424837a068 100644
--- a/desktop/src/features/agents/ui/AgentSessionToolItem/CompactMessageSummary.tsx
+++ b/desktop/src/features/agents/ui/AgentSessionToolItem/CompactMessageSummary.tsx
@@ -13,6 +13,7 @@ import { useTranscriptBubbleOverflow } from "../activityRenderClasses/useTranscr
 import { compactSummaryTone } from "./CompactToolSummaryRow";
 import type { SentMessageLink } from "./messageLinks";
 import { SentMessageContextDialog } from "./SentMessageContextDialog";
+import { useSentMessageBody } from "./useSentMessageBody";
 
 export function CompactMessageSummary({
   args,
@@ -46,6 +47,7 @@ export function CompactMessageSummary({
   timestamp: string;
 }) {
   const [detailsOpen, setDetailsOpen] = React.useState(false);
+  const resolvedContent = useSentMessageBody(messageLink, preview);
   const variant = useAgentSessionTranscriptVariant();
   const { goChannel } = useAppNavigation();
   const { openProfilePanel } = useProfilePanel();
@@ -159,7 +161,7 @@ export function CompactMessageSummary({
           >
             <Markdown
               className={isCompactPreview ? "text-xs leading-4" : "leading-5"}
-              content={preview || "Message content unavailable."}
+              content={resolvedContent || "Message content unavailable."}
             />
             {hasBubbleOverflow ? (
               <span
diff --git a/desktop/src/features/agents/ui/AgentSessionToolItem/useSentMessageBody.test.mjs b/desktop/src/features/agents/ui/AgentSessionToolItem/useSentMessageBody.test.mjs
new file mode 100644
index 0000000000..e880fff42b
--- /dev/null
+++ b/desktop/src/features/agents/ui/AgentSessionToolItem/useSentMessageBody.test.mjs
@@ -0,0 +1,174 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import {
+  QueryClient,
+  QueryClientProvider,
+  QueryObserver,
+} from "@tanstack/react-query";
+import React from "react";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import {
+  resolveSentMessageBody,
+  sentMessageBodyQueryOptions,
+  shouldFetchSentMessage,
+  useSentMessageBody,
+} from "./useSentMessageBody.ts";
+
+const link = { channelId: "ch-1", messageId: "ev-1" };
+
+test("shouldFetchSentMessage returns true when messageLink present and no inline content", () => {
+  assert.equal(shouldFetchSentMessage(link, null), true);
+});
+
+test("shouldFetchSentMessage returns false when inline content is present", () => {
+  assert.equal(shouldFetchSentMessage(link, "hello"), false);
+});
+
+test("shouldFetchSentMessage returns false when messageLink is null", () => {
+  assert.equal(shouldFetchSentMessage(null, null), false);
+});
+
+test("resolveSentMessageBody returns inline content over fetched content", () => {
+  assert.equal(
+    resolveSentMessageBody("inline text", "fetched text"),
+    "inline text",
+  );
+});
+
+test("resolveSentMessageBody returns fetched content when no inline content", () => {
+  assert.equal(resolveSentMessageBody(null, "fetched text"), "fetched text");
+});
+
+test("resolveSentMessageBody returns null when both inline and fetched are absent", () => {
+  assert.equal(resolveSentMessageBody(null, undefined), null);
+  assert.equal(resolveSentMessageBody(null, null), null);
+});
+
+// ── Integration: the real useQuery wiring, not just the pure helpers ──────────
+//
+// `sentMessageBodyQueryOptions` is the exact options object `useSentMessageBody`
+// hands to `useQuery`. Driving it through query-core's `QueryObserver` (what
+// `useQuery` constructs under the hood) exercises the production fetch/cache
+// wiring without a DOM — these tests fail if the hook stops calling the
+// injected fetcher, stops keying by `messageId`, or stops gating on
+// `enabled`.
+
+test("useSentMessageBody wiring fetches by messageId and resolves fetched content", async () => {
+  const queryClient = new QueryClient();
+  let calledWith = null;
+  const fetchEventById = async (eventId) => {
+    calledWith = eventId;
+    return { content: "hello from the event" };
+  };
+  const options = sentMessageBodyQueryOptions(link, null, fetchEventById);
+  const observer = new QueryObserver(queryClient, options);
+  const unsubscribe = observer.subscribe(() => {});
+  await new Promise((resolve) => setTimeout(resolve, 20));
+  unsubscribe();
+
+  assert.equal(calledWith, "ev-1");
+  assert.equal(
+    resolveSentMessageBody(null, observer.getCurrentResult().data?.content),
+    "hello from the event",
+  );
+});
+
+test("useSentMessageBody wiring never invokes the fetcher when inline content is present", async () => {
+  const queryClient = new QueryClient();
+  let called = false;
+  const fetchEventById = async () => {
+    called = true;
+    return { content: "unused" };
+  };
+  const options = sentMessageBodyQueryOptions(
+    link,
+    "inline text",
+    fetchEventById,
+  );
+  const observer = new QueryObserver(queryClient, options);
+  const unsubscribe = observer.subscribe(() => {});
+  await new Promise((resolve) => setTimeout(resolve, 20));
+  unsubscribe();
+
+  assert.equal(called, false);
+});
+
+test("useSentMessageBody wiring leaves data undefined on a rejected fetch (fetch-miss path)", async () => {
+  const queryClient = new QueryClient();
+  const fetchEventById = async () => {
+    throw new Error("relay miss");
+  };
+  const options = sentMessageBodyQueryOptions(link, null, fetchEventById);
+  const observer = new QueryObserver(queryClient, { ...options, retry: false });
+  const unsubscribe = observer.subscribe(() => {});
+  await new Promise((resolve) => setTimeout(resolve, 20));
+  unsubscribe();
+
+  assert.equal(observer.getCurrentResult().data, undefined);
+});
+
+// ── Render-level coverage ──────────────────────────────────────────────────
+//
+// Renders the hook through a real QueryClientProvider. Cache is pre-seeded
+// via `setQueryData` (equivalent to a settled fetch) for the render
+// assertion, since `renderToStaticMarkup` never commits and so never runs
+// the query's mount effect — the wiring tests above already prove the
+// fetcher is called through the real `useQuery` path.
+
+function SentMessageBodyProbe({ messageLink, inlineContent, fetchEventById }) {
+  const content = useSentMessageBody(
+    messageLink,
+    inlineContent,
+    fetchEventById,
+  );
+  return React.createElement(
+    "span",
+    null,
+    content ?? "Message content unavailable.",
+  );
+}
+
+function renderProbe(queryClient, props) {
+  return renderToStaticMarkup(
+    React.createElement(
+      QueryClientProvider,
+      { client: queryClient },
+      React.createElement(SentMessageBodyProbe, props),
+    ),
+  );
+}
+
+test("CompactMessageSummary renders fetched event content when a cached fetch has resolved", () => {
+  const queryClient = new QueryClient();
+  queryClient.setQueryData(["sent-message-body", link.messageId], {
+    content: "hello from the event",
+  });
+  const fetchEventById = async () => {
+    throw new Error("should not be called — cache hit");
+  };
+
+  const html = renderProbe(queryClient, {
+    messageLink: link,
+    inlineContent: null,
+    fetchEventById,
+  });
+
+  assert.match(html, /hello from the event/);
+});
+
+test("CompactMessageSummary renders the placeholder, never a raw flag value, on a fetch miss", () => {
+  const queryClient = new QueryClient();
+  const fetchEventById = async () => {
+    throw new Error("relay miss");
+  };
+
+  const html = renderProbe(queryClient, {
+    messageLink: link,
+    inlineContent: null,
+    fetchEventById,
+  });
+
+  assert.match(html, /Message content unavailable\./);
+});
diff --git a/desktop/src/features/agents/ui/AgentSessionToolItem/useSentMessageBody.ts b/desktop/src/features/agents/ui/AgentSessionToolItem/useSentMessageBody.ts
new file mode 100644
index 0000000000..e1b16dd862
--- /dev/null
+++ b/desktop/src/features/agents/ui/AgentSessionToolItem/useSentMessageBody.ts
@@ -0,0 +1,51 @@
+import { useQuery } from "@tanstack/react-query";
+
+import { getEventById } from "@/shared/api/tauri";
+import type { SentMessageLink } from "./messageLinks";
+
+export function shouldFetchSentMessage(
+  messageLink: SentMessageLink | null,
+  inlineContent: string | null,
+): boolean {
+  return messageLink !== null && inlineContent === null;
+}
+
+export function resolveSentMessageBody(
+  inlineContent: string | null,
+  fetchedContent: string | undefined | null,
+): string | null {
+  if (inlineContent) return inlineContent;
+  return fetchedContent ?? null;
+}
+
+/**
+ * Builds the exact options object `useSentMessageBody` passes to `useQuery`.
+ * Extracted so tests can drive the real fetch through query-core's
+ * `QueryObserver` (what `useQuery` constructs internally) without a DOM.
+ */
+export function sentMessageBodyQueryOptions(
+  messageLink: SentMessageLink | null,
+  inlineContent: string | null,
+  fetchEventById: (eventId: string) => Promise<{ content: string }>,
+) {
+  return {
+    queryKey: ["sent-message-body", messageLink?.messageId],
+    queryFn: () => fetchEventById(messageLink?.messageId ?? ""),
+    enabled: shouldFetchSentMessage(messageLink, inlineContent),
+    staleTime: Number.POSITIVE_INFINITY,
+  };
+}
+
+export function useSentMessageBody(
+  messageLink: SentMessageLink | null,
+  inlineContent: string | null,
+  fetchEventById: (
+    eventId: string,
+  ) => Promise<{ content: string }> = getEventById,
+): string | null {
+  const { data } = useQuery(
+    sentMessageBodyQueryOptions(messageLink, inlineContent, fetchEventById),
+  );
+
+  return resolveSentMessageBody(inlineContent, data?.content);
+}
diff --git a/desktop/src/features/agents/ui/agentSessionToolClassifier.test.mjs b/desktop/src/features/agents/ui/agentSessionToolClassifier.test.mjs
index 10efb79cb4..01a73c7698 100644
--- a/desktop/src/features/agents/ui/agentSessionToolClassifier.test.mjs
+++ b/desktop/src/features/agents/ui/agentSessionToolClassifier.test.mjs
@@ -3,7 +3,6 @@ import test from "node:test";
 
 import {
   classifyTool,
-  extractSimpleEchoPipeContent,
   parseBuzzCliCommand,
   tokenizeShellCommand,
 } from "./agentSessionToolClassifier.ts";
@@ -32,25 +31,96 @@ test("tokenizeShellCommand preserves quoted strings and command separators", ()
   );
 });
 
-test("extractSimpleEchoPipeContent reads the simple echo before a buzz pipe", () => {
-  const tokens = tokenizeShellCommand(
-    'echo -n "Done. Eat my shorts." | buzz messages send --content - --channel agents',
+test("parseBuzzCliCommand returns null preview for echo-piped stdin sends", () => {
+  const descriptor = parseBuzzCliCommand(
+    'echo "Permission wired" | buzz messages send --channel agents --content -',
   );
-  assert.equal(
-    extractSimpleEchoPipeContent(tokens, tokens.indexOf("buzz")),
-    "Done. Eat my shorts.",
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.label, "Send Message");
+  assert.equal(descriptor?.preview, null);
+  assert.equal(descriptor?.operation, "messages.send");
+});
+
+test("parseBuzzCliCommand returns null preview for printf-piped stdin sends", () => {
+  const descriptor = parseBuzzCliCommand(
+    "printf 'hello\\n\\nworld\\n' | buzz messages send --channel a6e0737c-4205-4bcc-9741-2aad800e613f --content -",
   );
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.preview, null);
 });
 
-test("parseBuzzCliCommand promotes buzz message sends to message descriptors", () => {
+test("parseBuzzCliCommand returns null preview for heredoc/cat stdin sends", () => {
   const descriptor = parseBuzzCliCommand(
-    'echo "Permission wired" | buzz messages send --channel agents --content -',
+    'buzz messages send --channel some-uuid --content "$(cat /tmp/file)"',
   );
 
   assert.equal(descriptor?.renderClass, "message");
-  assert.equal(descriptor?.label, "Send Message");
-  assert.equal(descriptor?.preview, "Permission wired");
-  assert.equal(descriptor?.operation, "messages.send");
+  assert.equal(descriptor?.preview, null);
+});
+
+test("parseBuzzCliCommand returns null preview for --content with embedded command substitution", () => {
+  const descriptor = parseBuzzCliCommand(
+    'buzz messages send --channel some-uuid --content "prefix $(cat /tmp/f)"',
+  );
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.preview, null);
+});
+
+test("parseBuzzCliCommand returns null preview for --content with a bare variable", () => {
+  const descriptor = parseBuzzCliCommand(
+    'buzz messages send --channel some-uuid --content "$MESSAGE"',
+  );
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.preview, null);
+});
+
+test("parseBuzzCliCommand returns null preview for --content with a prefixed variable", () => {
+  const descriptor = parseBuzzCliCommand(
+    'buzz messages send --channel some-uuid --content "prefix $MESSAGE"',
+  );
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.preview, null);
+});
+
+test("parseBuzzCliCommand preserves inline --content for sends", () => {
+  const descriptor = parseBuzzCliCommand(
+    'buzz messages send --channel agents --content "Hello from inline"',
+  );
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.preview, "Hello from inline");
+});
+
+test("parseBuzzCliCommand preserves --content=inline for sends", () => {
+  const descriptor = parseBuzzCliCommand(
+    "buzz messages send --channel agents --content=Acknowledged",
+  );
+
+  assert.equal(descriptor?.renderClass, "message");
+  assert.equal(descriptor?.preview, "Acknowledged");
+});
+
+test("parseBuzzCliCommand never surfaces --channel as preview for sends", () => {
+  const commands = [
+    "printf 'msg' | buzz messages send --channel my-uuid --content -",
+    'buzz messages send --channel my-uuid --content "$(cat /tmp/f)"',
+    "buzz messages send --channel my-uuid --content -",
+  ];
+
+  for (const cmd of commands) {
+    const descriptor = parseBuzzCliCommand(cmd);
+    assert.equal(descriptor?.renderClass, "message");
+    assert.notEqual(
+      descriptor?.preview,
+      "my-uuid",
+      `send preview leaked --channel for: ${cmd}`,
+    );
+  }
 });
 
 test("classifyTool promotes load_skill to skill-read descriptors", () => {
diff --git a/desktop/src/features/agents/ui/agentSessionToolClassifier.ts b/desktop/src/features/agents/ui/agentSessionToolClassifier.ts
index 67f6271344..10fb74b145 100644
--- a/desktop/src/features/agents/ui/agentSessionToolClassifier.ts
+++ b/desktop/src/features/agents/ui/agentSessionToolClassifier.ts
@@ -363,15 +363,13 @@ export function parseBuzzCliCommand(
   const group = tokens[range.groupIndex];
   const verb = tokens[range.verbIndex] ?? "run";
   const operation = `${group}.${verb}`;
-  const content =
-    group === "messages" && verb === "send"
-      ? extractBuzzCliSendMessageContent(tokens, range)
-      : null;
-  const preview = content ?? extractBuzzCliObjectPreview(tokens, range);
+  const isSend = group === "messages" && verb === "send";
+  const preview = isSend
+    ? extractBuzzCliInlineContent(tokens, range)
+    : extractBuzzCliObjectPreview(tokens, range);
   const tone = buzzCliTone(group, verb);
   return {
-    renderClass:
-      group === "messages" && verb === "send" ? "message" : "relay-op",
+    renderClass: isSend ? "message" : "relay-op",
     label: titleForBuzzCli(group, verb),
     preview,
     action: actionForBuzzOperation(operation, preview, tone),
@@ -452,14 +450,14 @@ function buzzCliTone(group: string, verb: string): AgentActivityTone {
   return "write";
 }
 
-function extractBuzzCliSendMessageContent(
+function extractBuzzCliInlineContent(
   tokens: string[],
   range: BuzzCommandRange,
 ): string | null {
   const content = getFlagValue(tokens, range.verbIndex + 1, "--content");
-  if (!content) return null;
-  if (content !== "-") return content;
-  return extractSimpleEchoPipeContent(tokens, range.buzzIndex) ?? null;
+  if (!content || content === "-") return null;
+  if (content.includes("$") || content.includes("`")) return null;
+  return content;
 }
 
 function extractBuzzCliObjectPreview(
@@ -583,28 +581,6 @@ function getFlagValue(tokens: string[], start: number, flag: string) {
   return null;
 }
 
-export function extractSimpleEchoPipeContent(
-  tokens: string[],
-  buzzIndex: number,
-): string | null {
-  const pipeIndex = tokens.lastIndexOf("|", buzzIndex);
-  if (pipeIndex <= 0) return null;
-  const echoStart = findSegmentStart(tokens, pipeIndex - 1);
-  const leftSegment = tokens.slice(echoStart, pipeIndex);
-  if (leftSegment[0] !== "echo") return null;
-  const contentTokens = leftSegment
-    .slice(1)
-    .filter((token) => !token.startsWith("-"));
-  return contentTokens.length > 0 ? contentTokens.join(" ") : null;
-}
-
-function findSegmentStart(tokens: string[], beforeIndex: number) {
-  for (let i = beforeIndex; i >= 0; i--) {
-    if (isCommandSeparator(tokens[i])) return i + 1;
-  }
-  return 0;
-}
-
 function extractBuzzToolPreview(args: Record<string, unknown>): string | null {
   const content = getToolString(args, ["content", "message", "text", "body"]);
   if (content) return content;
diff --git a/desktop/src/features/agents/ui/agentSessionToolSummary.test.mjs b/desktop/src/features/agents/ui/agentSessionToolSummary.test.mjs
index fab1f539ae..ca83ab8b43 100644
--- a/desktop/src/features/agents/ui/agentSessionToolSummary.test.mjs
+++ b/desktop/src/features/agents/ui/agentSessionToolSummary.test.mjs
@@ -56,7 +56,7 @@ test("buildCompactToolSummary treats buzz messages send commands as messages", (
   assert.equal(summary.presentation, "message");
 });
 
-test("buildCompactToolSummary extracts simple piped buzz message content", () => {
+test("buildCompactToolSummary returns null preview for piped stdin sends", () => {
   const summary = buildCompactToolSummary(
     makeTool({
       toolName: "shell",
@@ -68,7 +68,7 @@ test("buildCompactToolSummary extracts simple piped buzz message content", () =>
   );
 
   assert.equal(summary.label, "Send Message");
-  assert.equal(summary.preview, "hello from stdin");
+  assert.equal(summary.preview, null);
   assert.equal(summary.presentation, "message");
 });