feat(coding-agent): added coding-agent approval types and mode options

- Added `ToolTier`, `ToolApproval`, and `ToolApprovalDecision` types and exported approval APIs.
- Updated approval-mode options from `auto|prompt|custom` to `always-ask|write|yolo` and defaulted mode to `yolo`.
- Changed approval resolution to apply per-tool decisions first, then mode-tier limits, with legacy-mode migration.
- Assigned read/write/exec `approval` and approval-detail prompts across built-in, custom, extension, and MCP tools.

packages/coding-agent/src/task/executor.ts

@@ -533,10 +533,10 @@ function createSubagentSettings(baseSettings: Settings): Settings {
 		"async.enabled": false,
 		"bash.autoBackground.enabled": false,
 		// Subagents run headless — there is no UI to confirm prompts against, so
-		// any non-auto mode would deadlock on the first destructive call. The
-		// parent's approval of the `task` invocation is the user's authorization
-		// for the work the subagent performs.
-		"tools.approvalMode": "auto",
+		// the parent task approval is the authorization boundary. Use yolo mode
+		// to preserve unattended subagent execution while still honoring any
+		// tool-level safety override that can be handled before execution.
+		"tools.approvalMode": "yolo",
 	});
 }
 

packages/coding-agent/src/task/index.ts

@@ -27,6 +27,7 @@ import planModeSubagentPrompt from "../prompts/system/plan-mode-subagent.md" wit
 import subagentUserPromptTemplate from "../prompts/system/subagent-user-prompt.md" with { type: "text" };
 import taskDescriptionTemplate from "../prompts/tools/task.md" with { type: "text" };
 import taskSummaryTemplate from "../prompts/tools/task-summary.md" with { type: "text" };
+import { truncateForPrompt } from "../tools/approval";
 import { formatBytes, formatDuration } from "../tools/render-utils";
 import {
 	type AgentDefinition,
@@ -214,6 +215,24 @@ function validateTaskModeParams(simpleMode: TaskSimpleMode, params: TaskParams):
  */
 export class TaskTool implements AgentTool<TaskToolSchemaInstance, TaskToolDetails, Theme> {
 	readonly name = "task";
+	readonly approval = "exec" as const;
+	readonly formatApprovalDetails = (args: unknown): string[] => {
+		const params = args as Partial<TaskParams>;
+		const lines: string[] = [];
+		if (typeof params.agent === "string") {
+			lines.push(`Agent: ${truncateForPrompt(params.agent)}`);
+		}
+		const tasks = Array.isArray(params.tasks) ? params.tasks : [];
+		const firstTask = tasks[0];
+		if (firstTask) {
+			lines.push(`Task: ${truncateForPrompt(firstTask.id)}`);
+			lines.push(`Assignment:\n${truncateForPrompt(firstTask.assignment)}`);
+			if (tasks.length > 1) {
+				lines.push(`+${tasks.length - 1} more task${tasks.length === 2 ? "" : "s"}`);
+			}
+		}
+		return lines;
+	};
 	readonly label = "Task";
 	readonly summary = "Spawn a subagent to complete a parallel task";
 	readonly strict = true;