feat(KB-176): complete Step 4 — update executor system prompt and task_done tool

packages/core/src/store.ts

@@ -550,7 +550,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
 
   async updateTask(
     id: string,
-    updates: { title?: string; description?: string; prompt?: string; worktree?: string; status?: string | null; dependencies?: string[]; blockedBy?: string | null; paused?: boolean; baseBranch?: string; size?: "S" | "M" | "L"; reviewLevel?: number; mergeRetries?: number; modelProvider?: string | null; modelId?: string | null; validatorModelProvider?: string | null; validatorModelId?: string | null; error?: string | null },
+    updates: { title?: string; description?: string; prompt?: string; worktree?: string; status?: string | null; dependencies?: string[]; blockedBy?: string | null; paused?: boolean; baseBranch?: string; size?: "S" | "M" | "L"; reviewLevel?: number; mergeRetries?: number; modelProvider?: string | null; modelId?: string | null; validatorModelProvider?: string | null; validatorModelId?: string | null; error?: string | null; summary?: string | null },
   ): Promise<Task> {
     return this.withTaskLock(id, async () => {
       const dir = this.taskDir(id);
@@ -623,6 +623,11 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       } else if (updates.error !== undefined) {
         task.error = updates.error;
       }
+      if (updates.summary === null) {
+        task.summary = undefined;
+      } else if (updates.summary !== undefined) {
+        task.summary = updates.summary;
+      }
       task.updatedAt = new Date().toISOString();
 
       await this.atomicWriteTaskJson(dir, task);

packages/core/src/types.ts

@@ -186,6 +186,8 @@ export interface Task {
   mergeRetries?: number;
   /** Error message from the last failure, if the task failed during execution */
   error?: string;
+  /** Optional summary of what was changed/fixed when task is completed */
+  summary?: string;
   /** ISO-8601 timestamp of when the task last entered its current column.
    *  Used to sort cards within a column so that recently-moved cards appear at the top. */
   columnMovedAt?: string;

packages/engine/src/executor.ts

@@ -773,9 +773,14 @@ export class TaskExecutor {
       description:
         "Signal that all steps are complete, tests pass, and documentation is updated. " +
         "Call this as the final action after finishing all work. " +
-        "Automatically marks all remaining steps as done.",
+        "Automatically marks all remaining steps as done. " +
-      parameters: Type.Object({}),
+        "Optionally provide a summary of what was changed/fixed.",
-      execute: async () => {
+      parameters: Type.Object({
+        summary: Type.Optional(Type.String({
+          description: "Optional summary of what was changed/fixed and what was verified (2-4 sentences)",
+        })),
+      }),
+      execute: async (_id: string, params: { summary?: string }) => {
         onDone();
         // Mark all pending/in-progress steps as done
         const task = await store.getTask(taskId);
@@ -784,9 +789,16 @@ export class TaskExecutor {
             await store.updateStep(taskId, i, "done");
           }
         }
+        // Save summary if provided
+        if (params.summary) {
+          await store.updateTask(taskId, { summary: params.summary });
+        }
         await store.logEntry(taskId, "Task marked done by agent");
+        const successMessage = params.summary
+          ? "Task marked complete with summary. All steps done. Moving to in-review."
+          : "Task marked complete. All steps done. Moving to in-review.";
         return {
-          content: [{ type: "text" as const, text: "Task marked complete. All steps done. Moving to in-review." }],
+          content: [{ type: "text" as const, text: successMessage }],
           details: {},
         };
       },