feat: add Grok as a --guest runtime for Codex $cc commands (v1.7.3)

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Let `$cc:review`, `$cc:adversarial-review`, `$cc:rescue`, and `$cc:setup` run Grok as the guest via `--guest grok` or `CC_GUEST=grok`. The default guest remains Claude; Grok uses `--prompt-file` plus `--output-format json` and does not inherit Claude model aliases or Claude MCP tools. `$cc:design` and `$cc:research` stay Claude-only.
+
 ## v1.7.3
 
 ### Fixed

README.md

@@ -138,10 +138,12 @@ $cc:review --model opus --effort high   # opus with a lighter effort
 $cc:review --user-mcp-tool mcp__context7__resolve-library-id
 ```
 
-**Flags:** `--base <ref>`, `--scope <auto|working-tree|branch>`, `--wait`, `--background`, `--model <model>`, `--effort <low|medium|high|xhigh|max>`, `--user-mcp-tool <mcp__server__tool>`, `--allow-project-mcp-servers`
+**Flags:** `--base <ref>`, `--scope <auto|working-tree|branch>`, `--wait`, `--background`, `--guest <claude|grok>`, `--model <model>`, `--effort <low|medium|high|xhigh|max>`, `--user-mcp-tool <mcp__server__tool>`, `--allow-project-mcp-servers`
 
 **Defaults:** model `opus` is passed to Claude Code as its native alias with `xhigh` effort. `sonnet` is passed through with `high` effort; `haiku` and `fable` are passed through with no default effort setting. Claude Code resolves aliases to the current model for the active provider and account (for example, Opus 5). Pass a full model ID to pin a version; for older pinned IDs, pass `--effort` explicitly instead of inheriting a current-family default.
 
+`--guest` selects the companion runtime. The default is `claude`. Pass `--guest grok` (or set `CC_GUEST=grok`) to run Grok headless instead of Claude Code. Grok does not inherit Claude aliases such as `opus`; omit `--model` to use Grok's default, or pass a Grok model ID such as `grok-4.6`. `--user-mcp-tool` and `--allow-project-mcp-servers` remain Claude-only. `$cc:design` and `$cc:research` stay Claude-only.
+
 Fable 5.1 (`claude-fable-5-1`) has a native 1M context window and requires Claude Code 2.1.257 or newer. The bare `fable` alias remains floating and may still resolve to Fable 5 behind Claude Apps Gateway; use the full model ID when Fable 5.1 is required. No `[1m]` suffix or hidden Fable effort default is added. See Claude Code's [model configuration](https://code.claude.com/docs/en/model-config).
 
 JSON task and review results keep `requestedModel` as the forwarded alias or full ID, report `finalModel` from Claude's terminal result, and expose the terminal `contextWindow` reported in `modelUsage` (`null` when Claude does not provide it). The plugin does not infer a context limit from a floating alias.
@@ -227,7 +229,8 @@ $cc:rescue --model sonnet --effort medium investigate the flaky test
 | `--resume-last` | Alias for `--resume` |
 | `--fresh` | Force a new task (don't resume) |
 | `--write` | Allow file edits (default) |
-| `--model <model>` | Claude model (`opus`, `sonnet`, `haiku`, `fable`, or full ID; defaults to `opus`). Aliases are resolved by Claude Code; a full ID pins a version. |
+| `--guest <claude\|grok>` | Guest runtime (default `claude`). `grok` spawns `grok --prompt-file` instead of `claude -p`. Not used by `$cc:design` / `$cc:research`. |
+| `--model <model>` | Claude model (`opus`, `sonnet`, `haiku`, `fable`, or full ID; defaults to `opus`). Aliases are resolved by Claude Code; a full ID pins a version. For `--guest grok`, pass a Grok model ID or omit `--model`. |
 | `--effort <level>` | Reasoning effort: `low`, `medium`, `high`, `xhigh`, `max` (default: `xhigh` for opus, `high` for sonnet, unset for haiku and fable) |
 | `--prompt-file <path>` | Read task description from a file |
 | `--view-state on-terminal` | Mark the foreground terminal outcome as viewed |

internal-skills/cli-runtime/runtime.md

@@ -23,7 +23,8 @@ Command selection:
 - The caller's background or foreground choice changes only subagent execution. It does not change the companion command you build.
 
 Routing controls:
-- Treat `--cwd`, `--model`, `--effort`, `--resume`, `--resume-last`, `--fresh`, `--prompt-file`, `--view-state`, `--owner-session-id`, and `--job-id` as routing controls, not task text.
+- Treat `--cwd`, `--guest`, `--model`, `--effort`, `--resume`, `--resume-last`, `--fresh`, `--prompt-file`, `--view-state`, `--owner-session-id`, and `--job-id` as routing controls, not task text.
+- Preserve `--guest` when present. Default guest is `claude`; `--guest grok` runs Grok instead of Claude Code. `$cc:design` and `$cc:research` stay Claude-only.
 - Preserve the parent helper's exact non-empty `workspaceRoot` as `--cwd "<workspaceRoot>"`; never substitute the plugin root or the child's default working directory.
 - Leave `--model` and `--effort` unset unless the user explicitly asks for a specific model or effort. The companion command applies these defaults itself: model defaults to `opus`, effort defaults to `xhigh` for opus, `high` for sonnet, and is left unset for haiku and fable.
 - `--view-state on-terminal` means the user will see this companion result in the current turn, so the companion may mark any terminal outcome viewed.

internal-skills/review-runtime/runtime.md

@@ -16,6 +16,7 @@ Execution boundary:
 
 Foreground contract:
 - Strip `--wait` and `--background` before building the companion command.
+- Preserve `--guest` when present. Default guest is `claude`; `--guest grok` runs Grok instead of Claude Code.
 - Keep the shell tool in the active user workspace; do not set its working directory to the plugin path.
 - Foreground command:
   - `review --view-state on-terminal ...`