chore: import upstream snapshot with attribution

apps/sim/tools/file/append.ts

@@ -0,0 +1,58 @@
+import type { ToolConfig, ToolResponse, WorkflowToolExecutionContext } from '@/tools/types'
+
+interface FileAppendParams {
+  fileName: string
+  content: string
+  workspaceId?: string
+  _context?: WorkflowToolExecutionContext
+}
+
+export const fileAppendTool: ToolConfig<FileAppendParams, ToolResponse> = {
+  id: 'file_append',
+  name: 'File Append',
+  description:
+    'Append content to an existing workspace file. The file must already exist. Content is added to the end of the file.',
+  version: '1.0.0',
+
+  params: {
+    fileName: {
+      type: 'string',
+      required: true,
+      visibility: 'user-or-llm',
+      description: 'Name of an existing workspace file to append to.',
+    },
+    content: {
+      type: 'string',
+      required: true,
+      visibility: 'user-or-llm',
+      description: 'The text content to append to the file.',
+    },
+  },
+
+  request: {
+    url: '/api/tools/file/manage',
+    method: 'POST',
+    headers: () => ({ 'Content-Type': 'application/json' }),
+    body: (params) => ({
+      operation: 'append',
+      fileName: params.fileName,
+      content: params.content,
+      workspaceId: params.workspaceId || params._context?.workspaceId,
+    }),
+  },
+
+  transformResponse: async (response) => {
+    const data = await response.json()
+    if (!response.ok || !data.success) {
+      return { success: false, output: {}, error: data.error || 'Failed to append to file' }
+    }
+    return { success: true, output: data.data }
+  },
+
+  outputs: {
+    id: { type: 'string', description: 'File ID' },
+    name: { type: 'string', description: 'File name' },
+    size: { type: 'number', description: 'File size in bytes' },
+    url: { type: 'string', description: 'URL to access the file', optional: true },
+  },
+}