Add js_repl_tools_only model and routing restrictions (#10671)

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#### [git stack](https://github.com/magus/git-stack-cli)
- ✅ `1` https://github.com/openai/codex/pull/10674
- ✅ `2` https://github.com/openai/codex/pull/10672
- 👉 `3` https://github.com/openai/codex/pull/10671
- ⏳ `4` https://github.com/openai/codex/pull/10673
- ⏳ `5` https://github.com/openai/codex/pull/10670

codex-rs/core/src/project_doc.rs

@@ -48,6 +48,12 @@ fn render_js_repl_instructions(config: &Config) -> Option<String> {
     section.push_str("- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n");
     section.push_str("- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n");
 
+    if config.features.enabled(Feature::JsReplToolsOnly) {
+        section.push_str("- Do not call tools directly; use `js_repl` + `codex.tool(...)` for all tool calls, including shell commands.\n");
+        section
+            .push_str("- MCP tools (if any) can also be called by name via `codex.tool(...)`.\n");
+    }
+
     section.push_str("- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log` and `codex.tool(...)`.");
 
     Some(section)
@@ -413,6 +419,21 @@ mod tests {
         assert_eq!(res, expected);
     }
 
+    #[tokio::test]
+    async fn js_repl_tools_only_instructions_are_feature_gated() {
+        let tmp = tempfile::tempdir().expect("tempdir");
+        let mut cfg = make_config(&tmp, 4096, None).await;
+        cfg.features
+            .enable(Feature::JsRepl)
+            .enable(Feature::JsReplToolsOnly);
+
+        let res = get_user_instructions(&cfg, None)
+            .await
+            .expect("js_repl instructions expected");
+        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel. `codex.state` persists for the session (best effort) and is cleared by `js_repl_reset`.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.state`, `codex.tmpDir`, and `codex.tool(name, args?)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike.\n- To share generated images with the model, write a file under `codex.tmpDir`, call `await codex.tool(\"view_image\", { path: \"/absolute/path\" })`, then delete the file.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n- Do not call tools directly; use `js_repl` + `codex.tool(...)` for all tool calls, including shell commands.\n- MCP tools (if any) can also be called by name via `codex.tool(...)`.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log` and `codex.tool(...)`.";
+        assert_eq!(res, expected);
+    }
+
     /// When both system instructions *and* a project doc are present the two
     /// should be concatenated with the separator.
     #[tokio::test]