Add XAI Grok to the AI panel (#1558)

Grok Build is added as one more entry in the agent discovery list, over ACP, like the others. Thanks @cfaulkingham.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

docs/agent-chat.md

@@ -1,7 +1,7 @@
 # Agent chat
 
 Agent chat is a side panel where you talk to a coding agent you already use (Claude Code,
-Codex, Gemini CLI, OpenCode and others), or to a model behind an OpenAI-compatible endpoint you
+Codex, Gemini CLI, OpenCode, Grok Build and others), or to a model behind an OpenAI-compatible endpoint you
 choose (Ollama or LM Studio on your computer, OpenAI, any other URL), and have it work on the
 design that's open. A coding agent runs on your computer under **your own account** with that
 agent: SolidCraft doesn't sell or proxy a model and needs no key for it. An endpoint's key, if
@@ -53,7 +53,7 @@ conversation starts with), its own permission setting, and **Remove** for the on
 
 SolidCraft looks for agents that speak the [Agent Client Protocol](https://agentclientprotocol.com)
 on your `PATH` and in the usual install folders a desktop app's `PATH` often misses (npm's
-global folder, nvm, Volta, bun, `~/.local/bin`, Homebrew, `%APPDATA%\npm`). For each one it
+global folder, nvm, Volta, bun, `~/.local/bin`, `~/.grok/bin`, Homebrew, `%APPDATA%\npm`). For each one it
 shows its **version** (from `--version`, given three seconds) and whether it looks **signed in**.
 SolidCraft only checks whether the agent's own login file (`~/.claude/.credentials.json`,
 `~/.codex/auth.json`, `~/.gemini/oauth_creds.json`, …) or one of its key variables exists. It never
@@ -66,12 +66,26 @@ the keychain, so SolidCraft doesn't guess there.
 | Codex | `npm install -g @agentclientprotocol/codex-acp` |
 | Gemini CLI | `npm install -g @google/gemini-cli` (it speaks ACP itself: `gemini --acp`) |
 | OpenCode | `npm install -g opencode-ai` (`opencode acp`) |
+| XAI Grok | [Grok Build installer](https://docs.x.ai/build/overview), then `grok login` (`grok agent stdio` speaks ACP) |
 | GitHub Copilot CLI, Qwen Code, goose | listed with their install command when missing |
 
 The panel lists agents that aren't installed with their install command and a **Copy** button.
 **Refresh** looks again after you install one. **Test** starts an agent briefly, asks it for a
 session and ends it again.
 
+### XAI Grok
+
+Install **Grok Build** and run `grok login` in a terminal to sign in with your Grok account.
+In SolidCraft, open **AI → Refresh**, select
+**XAI Grok**, then **Connect**. You can make it the default under
+**Preferences → AI → Agents**.
+
+SolidCraft reuses Grok Build's sign-in in `~/.grok/auth.json`; it checks only whether that file
+exists and does not read or copy its tokens. If sign-in is needed, the panel offers Grok's own
+sign-in methods. You can also run `grok login` again and reconnect. Grok controls model access
+and usage limits for your account. This connection does not require an API key in SolidCraft.
+Grok Build also supports `XAI_API_KEY` for users who choose API authentication.
+
 ### Add agent…
 
 - **Installed agent:** your own entry for an installed agent, for example with other arguments.

docs/design/in-app-agent-chat.md

@@ -50,6 +50,7 @@ with SolidCraft, the user installs the agent.
 | Codex | `codex-acp` adapter (`@zed-industries/codex-acp` 0.16 moved to `@agentclientprotocol/codex-acp`) | `@agentclientprotocol/codex-acp` 2.2.2, Apache-2.0 | `--version` (0.16 rejected the flag; 2.x prints it) | Agent method `chat-gpt` (the adapter opens the browser for the ChatGPT login when the client calls `authenticate`), and `api-key` for a key the user configures in Codex. 0.16 also listed `env_var` methods for `CODEX_API_KEY` / `OPENAI_API_KEY`. The login is Codex's own: `~/.codex/auth.json`. |
 | Gemini CLI | built in: `gemini --acp` (the ACP registry's current flag; older releases used `--experimental-acp`) | `@google/gemini-cli` 0.64, Apache-2.0 | `--version` | Its own Google login (`~/.gemini/oauth_creds.json`) or a key in the environment. |
 | OpenCode | built in: `opencode acp` | `opencode-ai` 1.19, MIT | `--version` | Its own providers' logins (`~/.local/share/opencode/auth.json`) or keys in the environment. |
+| XAI Grok | built in: `grok agent stdio` | [Grok Build](https://github.com/xai-org/grok-build), Apache-2.0; installed separately | `grok --version` prints `grok 1.0.58 (…) [alpha]` (checked 2026-10-15; in-app connection also checked with 1.0.60) | Its own `~/.grok/auth.json` or `XAI_API_KEY`. `grok login` signs in in the browser; ACP advertises `cached_token` and `grok.com` authentication methods. |
 | Others in the ACP registry | `copilot --acp`, `qwen --acp`, `opencode acp`, `goose acp`, `cline --acp`, `kimi acp`, … | mixed; several are proprietary, one is GPL and one AGPL (we only start them as programs, never link them) | `--version` | each its own |
 
 The registry (`https://cdn.agentclientprotocol.com/registry/v1/latest/registry.json`) lists