diff --git a/skills/create-headless-agent/README.md b/skills/create-headless-agent/README.md
index 25d663a..7e047cd 100644
--- a/skills/create-headless-agent/README.md
+++ b/skills/create-headless-agent/README.md
@@ -58,6 +58,7 @@ The skill presents an interactive checklist when invoked:
 | Web Fetch | on | Fetch text content from a URL via `openrouter:web_fetch` |
 | Datetime | on | Current date/time via `openrouter:datetime` |
 | Image Generation | off | Generate images via `openrouter:image_generation` |
+| Shell | off | Sandbox command execution via `openrouter:shell` |
 
 ### User-defined tools (your code, executed locally)
 
@@ -127,7 +128,7 @@ my-agent/
     agent.test.ts           Example test (bun:test)
 ```
 
-Server tools (`openrouter:web_search`, `openrouter:web_fetch`, `openrouter:datetime`) are wired in `tools/index.ts` and execute on OpenRouter's side — no client code.
+Server tools (`openrouter:web_search`, `openrouter:web_fetch`, `openrouter:datetime`, `openrouter:shell`) are wired in `tools/index.ts` and execute on OpenRouter's side — no client code. `openrouter:shell` runs in the OpenRouter sandbox; use it for sandbox execution on Responses, while `openrouter:bash` with `engine: 'openrouter'` is Messages-only.
 
 ## Sample
 
diff --git a/skills/create-headless-agent/SKILL.md b/skills/create-headless-agent/SKILL.md
index cae0caf..45e5dd8 100644
--- a/skills/create-headless-agent/SKILL.md
+++ b/skills/create-headless-agent/SKILL.md
@@ -47,8 +47,9 @@ Present this as a multi-select checklist. Items marked **ON** are pre-selected d
 | Web Fetch | `openrouter:web_fetch` | ON |
 | Datetime | `openrouter:datetime` | ON |
 | Image Generation | `openrouter:image_generation` | OFF |
+| Shell | `openrouter:shell` | OFF |
 
-Server tools go in the `tools` array alongside user-defined tools. No client code needed — OpenRouter executes them. Docs: [openrouter.ai/docs/guides/features/server-tools](https://openrouter.ai/docs/guides/features/server-tools/overview).
+Server tools go in the `tools` array alongside user-defined tools. No client code needed — OpenRouter executes them. `openrouter:shell` runs in the OpenRouter sandbox; use it for sandbox execution on Responses, while `openrouter:bash` with `engine: 'openrouter'` is Messages-only. Docs: [openrouter.ai/docs/guides/features/server-tools](https://openrouter.ai/docs/guides/features/server-tools/overview).
 
 ### User-Defined Tools (client-side, generated into src/tools/)