sh-mcp/packages/tasks/src/tools.ts

/**
 * Task tools — ops tier, scope: ops:tasks
 *
 * All four tools (create_task, list_tasks, complete_task, delete_task) are
 * scoped to ops:tasks and operate on the calling user's tasks only (ABAC:
 * partition key = ctx.sub). The injected TasksClient is the only I/O path;
 * no AWS SDK or network call is made directly here.
 *
 * Finance-tier note: this is an ops-tier package. No finance fields are
 * present, so redact() is not called here. If this package is ever promoted
 * or a finance field is added, every sensitive field MUST be wrapped in
 * redact() before it is included in the tool output.
 */

import { defineTool, requireScope, type AuthContext } from '@sh-mcp/shared';
import type { TasksClient } from './client.js';

// ---------------------------------------------------------------------------
// Tool factory — accepts an injected TasksClient so tests can pass a mock.
// The MCP server entry point calls buildTaskTools(new DynamoDBTasksClient()).
// ---------------------------------------------------------------------------

export function buildTaskTools(client: TasksClient) {
  // -------------------------------------------------------------------------
  // create_task
  // -------------------------------------------------------------------------
  const createTask = defineTool<
    { title: string; description?: string },
    { task: { taskId: string; title: string; description?: string; completed: boolean; createdAt: string } }
  >({
    name: 'create_task',
    description:
      'Create a new task for the calling user. Tasks are private — only the user who created a task can see or modify it.',
    tier: 'ops',
    requiredScope: 'ops:tasks',
    inputSchema: {
      type: 'object',
      properties: {
        title: {
          type: 'string',
          minLength: 1,
          maxLength: 256,
          description: 'Short title for the task (required).',
        },
        description: {
          type: 'string',
          maxLength: 2048,
          description: 'Optional longer description or notes for the task.',
        },
      },
      required: ['title'],
      additionalProperties: false,
    },
    handler: async (input, ctx: AuthContext) => {
      requireScope(ctx, 'ops:tasks');
      const task = await client.createTask({
        sub: ctx.sub,
        title: input.title,
        description: input.description,
      });
      return {
        task: {
          taskId: task.taskId,
          title: task.title,
          description: task.description,
          completed: task.completed,
          createdAt: task.createdAt,
        },
      };
    },
  });

  // -------------------------------------------------------------------------
  // list_tasks
  // -------------------------------------------------------------------------
  const listTasks = defineTool<
    { includeCompleted?: boolean },
    { tasks: Array<{ taskId: string; title: string; description?: string; completed: boolean; createdAt: string; completedAt?: string }> }
  >({
    name: 'list_tasks',
    description:
      'List tasks belonging to the calling user. By default only incomplete tasks are returned; pass includeCompleted: true to see all.',
    tier: 'ops',
    requiredScope: 'ops:tasks',
    inputSchema: {
      type: 'object',
      properties: {
        includeCompleted: {
          type: 'boolean',
          description: 'When true, completed tasks are included in the results. Defaults to false.',
        },
      },
      additionalProperties: false,
    },
    handler: async (input, ctx: AuthContext) => {
      requireScope(ctx, 'ops:tasks');
      const tasks = await client.listTasks({
        sub: ctx.sub,
        includeCompleted: input.includeCompleted ?? false,
      });
      return {
        tasks: tasks.map((t) => ({
          taskId: t.taskId,
          title: t.title,
          description: t.description,
          completed: t.completed,
          createdAt: t.createdAt,
          completedAt: t.completedAt,
        })),
      };
    },
  });

  // -------------------------------------------------------------------------
  // complete_task
  // -------------------------------------------------------------------------
  const completeTask = defineTool<
    { taskId: string },
    { task: { taskId: string; title: string; completed: boolean; completedAt: string } }
  >({
    name: 'complete_task',
    description:
      "Mark a task as completed. The task must belong to the calling user; completing another user's task is not permitted.",
    tier: 'ops',
    requiredScope: 'ops:tasks',
    inputSchema: {
      type: 'object',
      properties: {
        taskId: {
          type: 'string',
          minLength: 1,
          description: 'The ID of the task to mark as completed.',
        },
      },
      required: ['taskId'],
      additionalProperties: false,
    },
    handler: async (input, ctx: AuthContext) => {
      requireScope(ctx, 'ops:tasks');
      const task = await client.completeTask({
        sub: ctx.sub,
        taskId: input.taskId,
      });
      return {
        task: {
          taskId: task.taskId,
          title: task.title,
          completed: task.completed,
          completedAt: task.completedAt as string,
        },
      };
    },
  });

  // -------------------------------------------------------------------------
  // delete_task
  // -------------------------------------------------------------------------
  const deleteTask = defineTool<{ taskId: string }, { deleted: true; taskId: string }>({
    name: 'delete_task',
    description:
      'Permanently delete a task belonging to the calling user. This action is irreversible.',
    tier: 'ops',
    requiredScope: 'ops:tasks',
    inputSchema: {
      type: 'object',
      properties: {
        taskId: {
          type: 'string',
          minLength: 1,
          description: 'The ID of the task to delete.',
        },
      },
      required: ['taskId'],
      additionalProperties: false,
    },
    handler: async (input, ctx: AuthContext) => {
      requireScope(ctx, 'ops:tasks');
      await client.deleteTask({
        sub: ctx.sub,
        taskId: input.taskId,
      });
      return { deleted: true, taskId: input.taskId };
    },
  });

  return [createTask, listTasks, completeTask, deleteTask] as const;
}