From 4d5c3c13d4b82792844b30a2b9c0eedf003be0e2 Mon Sep 17 00:00:00 2001
From: "paseo-bot[bot]" <266920839+paseo-bot[bot]@users.noreply.github.com>
Date: Thu, 15 Oct 2026 12:13:18 +0200
Subject: [PATCH] fix(acp): preserve slash command argument hints (#6920)

ACP command updates discarded input hints before the autocomplete command list reached consumers. Preserve the advertised hint, retaining the empty hint for commands without input metadata.

Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>
Co-authored-by: bwestlund17 <brian.westlund@proton.me>
---
 .../src/server/agent/providers/acp-agent.ts   |  2 +-
 .../generic-acp-agent.commands.test.ts        | 21 ++++++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/packages/server/src/server/agent/providers/acp-agent.ts b/packages/server/src/server/agent/providers/acp-agent.ts
index 169421fca9..3b61fcb863 100644
--- a/packages/server/src/server/agent/providers/acp-agent.ts
+++ b/packages/server/src/server/agent/providers/acp-agent.ts
@@ -3098,7 +3098,7 @@ export class ACPAgentSession implements AgentSession, ACPClient {
         this.cachedCommands = update.availableCommands.map((command) => ({
           name: command.name,
           description: command.description,
-          argumentHint: "",
+          argumentHint: command.input?.hint ?? "",
           kind: "command",
         }));
         this.settleCommandsReady();
diff --git a/packages/server/src/server/agent/providers/generic-acp-agent.commands.test.ts b/packages/server/src/server/agent/providers/generic-acp-agent.commands.test.ts
index 2411773a7e..3655cccb5b 100644
--- a/packages/server/src/server/agent/providers/generic-acp-agent.commands.test.ts
+++ b/packages/server/src/server/agent/providers/generic-acp-agent.commands.test.ts
@@ -8,7 +8,7 @@ import { createTestLogger } from "../../../test-utils/test-logger.js";
 import { GenericACPAgentClient } from "./generic-acp-agent.js";
 
 describe("GenericACPAgentClient slash commands", () => {
-  test("lists commands an agent advertises right after session/new", async () => {
+  test("preserves argument hints in commands advertised right after session/new", async () => {
     await withFakeACPAgent("commands-after-session-new", async (command, cwd) => {
       const client = new GenericACPAgentClient({
         logger: createTestLogger(),
@@ -17,9 +17,17 @@ describe("GenericACPAgentClient slash commands", () => {
       });
       const session = await client.createSession({ provider: "acp", cwd });
       try {
-        await expect(session.listCommands?.()).resolves.toEqual([
-          { name: "review", description: "Review the diff", argumentHint: "", kind: "command" },
-        ]);
+        const commands = [
+          {
+            name: "review",
+            description: "Review the diff",
+            argumentHint: "query",
+            kind: "command",
+          },
+          { name: "status", description: "Show status", argumentHint: "", kind: "command" },
+        ];
+        await expect(session.listCommands?.()).resolves.toEqual(commands);
+        await expect(session.listCommands?.()).resolves.toEqual(commands);
       } finally {
         await session.close();
       }
@@ -91,7 +99,10 @@ rl.on("line", (line) => {
               sessionId: "session-1",
               update: {
                 sessionUpdate: "available_commands_update",
-                availableCommands: [{ name: "review", description: "Review the diff" }],
+                availableCommands: [
+                  { name: "review", description: "Review the diff", input: { hint: "query" } },
+                  { name: "status", description: "Show status" },
+                ],
               },
             },
           },