diff --git a/.changeset/proud-eagles-chatter.md b/.changeset/proud-eagles-chatter.md
new file mode 100644
index 000000000..49f9b3016
--- /dev/null
+++ b/.changeset/proud-eagles-chatter.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 3097
+---
+**`/gsd` commands in Pi now display their output** — the command handler returned output as a bare string, which Pi's ExtensionAPI silently dropped. It now returns Pi's structured `{ content: [{ type: 'text', text }] }` display shape (matching the `gsd_invoke` tool's proven contract), so success output and error messages are visible. (#2991)
diff --git a/pi/gsd.cjs b/pi/gsd.cjs
index c30bd738a..9a3fdc702 100644
--- a/pi/gsd.cjs
+++ b/pi/gsd.cjs
@@ -287,11 +287,16 @@ module.exports = function gsdPiExtension(pi) {
       try {
         ({ dispatchGsdCommand } = require(path.join(GSD_CORE, 'bin', 'lib', 'shell-command-projection.cjs')));
       } catch (e) {
-        return `GSD engine unavailable: ${e && e.message ? e.message : String(e)}`;
+        // #2991: return the structured { content } shape Pi's ExtensionAPI
+        // displays, not a bare string (which Pi silently drops).
+        return { content: [{ type: 'text', text: `GSD engine unavailable: ${e && e.message ? e.message : String(e)}` }] };
       }
       const result = dispatchGsdCommand({ family, subcommand, args: rest, cwd });
-      if (result.ok) return result.stdout;
-      return `GSD error: ${result.stderr || result.stdout || `dispatch failed (exit ${result.code})`}`;
+      // #2991: match gsd_invoke's proven output shape so Pi actually displays it.
+      const text = result.ok
+        ? result.stdout
+        : `GSD error: ${result.stderr || result.stdout || `dispatch failed (exit ${result.code})`}`;
+      return { content: [{ type: 'text', text }] };
     },
   });
 
diff --git a/tests/pi-extension-reachability.test.cjs b/tests/pi-extension-reachability.test.cjs
index 8d51730cb..c2208f6b5 100644
--- a/tests/pi-extension-reachability.test.cjs
+++ b/tests/pi-extension-reachability.test.cjs
@@ -63,23 +63,28 @@ test('REACHABILITY: the /gsd handler dispatches a real family through gsd-tools.
   const dir = createTempDir();
   try {
     const result = await pi._recorded.commands['gsd'].handler('progress json', { cwd: dir });
-    assert.equal(typeof result, 'string', '/gsd handler returns a string result');
-    const parsed = JSON.parse(result);
+    // #2991: handler returns { content: [{ type: 'text', text }] } (Pi's display shape), not a bare string.
+    assert.ok(result && Array.isArray(result.content) && result.content[0].type === 'text',
+      `/gsd handler must return Pi's display shape { content: [{ type: 'text', text }] }; got: ${JSON.stringify(result).slice(0, 200)}`);
+    const parsed = JSON.parse(result.content[0].text);
     assert.equal(typeof parsed.percent, 'number', '/gsd dispatch reached gsd-tools.cjs for real (the engine was reached)');
   } finally {
     cleanup(dir);
   }
 });
 
-test('REACHABILITY: an unknown family surfaces a clear GSD error string, not a throw', async () => {
+test('REACHABILITY: an unknown family surfaces a clear GSD error, not a throw', async () => {
   const pi = mockPi();
   gsdPiExtension(pi);
   const dir = createTempDir();
   try {
     const result = await pi._recorded.commands['gsd'].handler('no-such-family-8675309', { cwd: dir });
-    assert.equal(typeof result, 'string');
-    assert.match(result, /GSD error:/);
-    assert.match(result, /no-such-family-8675309|Unknown command/);
+    // #2991: handler returns { content: [{ type: 'text', text }] } (Pi's display shape).
+    assert.ok(result && Array.isArray(result.content) && result.content[0].type === 'text',
+      `error result must carry Pi's display shape; got: ${JSON.stringify(result).slice(0, 200)}`);
+    const text = result.content[0].text;
+    assert.match(text, /GSD error:/);
+    assert.match(text, /no-such-family-8675309|Unknown command/);
   } finally {
     cleanup(dir);
   }