Restrict Guardian reviewer tools (#32945)

## What changed

- Limit Guardian reviewer sessions with an environment to `exec_command`,
  `write_stdin`, and `view_image`.
- Exclude general tool sources from Guardian reviewer tool planning.

## Testing

- Extend the Guardian request snapshot test to assert the exact model-visible
  tool list.

GitOrigin-RevId: 80ba7011c23c32d163aaad906087fac396cc70fa

codex-rs/core/src/guardian/tests.rs

@@ -1743,6 +1743,16 @@ async fn guardian_review_request_layout_matches_model_visible_request_snapshot()
     ));
     let request = request_log.single_request();
     let request_body = request.body_json();
+    let guardian_tool_names = request_body["tools"]
+        .as_array()
+        .expect("guardian request tools")
+        .iter()
+        .map(|tool| tool["name"].as_str().expect("guardian request tool name"))
+        .collect::<Vec<_>>();
+    assert_eq!(
+        guardian_tool_names,
+        vec!["exec_command", "write_stdin", "view_image"]
+    );
     let guardian_user_text = request.message_input_texts("user").join("\n");
     assert!(
         guardian_user_text.contains(&format!("${GUARDIAN_SKILL_NAME}")),

codex-rs/core/src/tools/spec_plan.rs

@@ -582,6 +582,33 @@ fn code_mode_namespace_descriptions(
 
 #[instrument(level = "trace", skip_all)]
 fn add_tool_sources(context: &CoreToolPlanContext<'_>, planned_tools: &mut PlannedTools) {
+    // Guardian reviewers receive only `exec_command`, `write_stdin`, and `view_image`
+    // when an environment is available; all general tool sources stay excluded.
+    if crate::guardian::is_guardian_reviewer_source(&context.step_context.turn.session_source) {
+        let turn_context = context.step_context.turn.as_ref();
+        let environment_mode = tool_environment_mode(context.step_context);
+        if environment_mode.has_environment() {
+            let include_environment_id = matches!(environment_mode, ToolEnvironmentMode::Multiple);
+            planned_tools.add(ExecCommandHandler::new(ExecCommandHandlerOptions {
+                allow_login_shell: turn_context.config.permissions.allow_login_shell,
+                exec_permission_approvals_enabled: false,
+                include_environment_id,
+                include_shell_parameter: unified_exec_should_include_shell_parameter(
+                    turn_context,
+                    context.step_context,
+                ),
+            }));
+            planned_tools.add(WriteStdinHandler);
+            planned_tools.add(ViewImageHandler::new(ViewImageToolOptions {
+                can_request_original_image_detail: can_request_original_image_detail(
+                    &turn_context.model_info,
+                ),
+                include_environment_id,
+            }));
+        }
+        return;
+    }
+
     add_shell_tools(context, planned_tools);
     add_mcp_resource_tools(context, planned_tools);
     add_core_utility_tools(context, planned_tools);