fix(chat): show Claude's slash commands from the moment a session opens

src/server/chat/adapters/claude.ts

@@ -1,7 +1,7 @@
 import { randomUUID } from 'node:crypto';
 import { readFileSync } from 'node:fs';
 import { BaseChatAdapter } from '../adapter.js';
-import { describeSlashCommand } from '../../../shared/slash-commands.js';
+import { defaultSlashCommands, describeSlashCommand } from '../../../shared/slash-commands.js';
 import {
   ChatAttachment,
   ChatBlock,
@@ -48,6 +48,11 @@ export class ClaudeChatAdapter extends BaseChatAdapter {
     usage: true,
     cost: true,
     plan: false,
+    // The real list only arrives with the first turn's `init` (see
+    // handleInit below); until then this is what makes the command menu and
+    // its composer button available from the moment the session opens,
+    // rather than staying empty until a message has already been sent.
+    commands: defaultSlashCommands(),
   };
 
   /** Session id we generated for a fresh launch, before init echoes it back. */

src/shared/slash-commands.ts

@@ -48,6 +48,21 @@ export function describeSlashCommand(name: string): string | undefined {
   return BUILT_IN[String(name || '').trim().toLowerCase().replace(/^\//, '')];
 }
 
+/**
+ * The built-ins, as a menu the picker can show before a runtime has said
+ * anything about itself.
+ *
+ * Claude does not report `slash_commands` until it has processed a first
+ * turn (see claude.ts), which used to mean a brand-new session showed no
+ * command menu at all until one message had already been sent. This table is
+ * this app's own knowledge of what a fresh Claude session accepts, not
+ * something Claude told it — a project or plugin command still only appears
+ * once the real `init` arrives and replaces this list outright.
+ */
+export function defaultSlashCommands(): { name: string; description: string }[] {
+  return Object.entries(BUILT_IN).map(([name, description]) => ({ name, description }));
+}
+
 /**
  * Commands that empty the conversation.
  *

test/chat-claude.test.js

@@ -295,7 +295,8 @@ describe('claude chat adapter', function () {
   describe('capabilities', function () {
     it('advertises streaming/thinking/toolCalls/resume/interrupt/attachments but not diffs or permissions', function () {
       const { adapter } = makeAdapter();
-      assert.deepStrictEqual(adapter.capabilities, {
+      const { commands, ...rest } = adapter.capabilities;
+      assert.deepStrictEqual(rest, {
         streaming: true,
         thinking: true,
         toolCalls: true,
@@ -310,5 +311,22 @@ describe('claude chat adapter', function () {
         plan: false,
       });
     });
+
+    it('advertises a baseline command list before the runtime has said anything', function () {
+      const { adapter } = makeAdapter();
+      assert.ok(adapter.capabilities.commands.length > 0);
+      assert.ok(adapter.capabilities.commands.some((c) => c.name === 'resume'));
+      assert.ok(adapter.capabilities.commands.every((c) => c.description));
+    });
+  });
+
+  describe('before the first turn', function () {
+    it('a freshly constructed adapter already has a non-empty command list, so the menu never starts empty', function () {
+      const { adapter } = makeAdapter();
+      // No handleMessage call at all here: this is the state the session sees
+      // the instant the process is spawned, before Claude has said a word.
+      assert.ok(Array.isArray(adapter.capabilities.commands));
+      assert.ok(adapter.capabilities.commands.length > 0);
+    });
   });
 });