fix(knowledge): infer MIME type from file extension in create/upsert tools

apps/sim/tools/knowledge/create_document.ts

@@ -1,4 +1,7 @@
-import type { KnowledgeCreateDocumentResponse } from '@/tools/knowledge/types'
+import {
+ inferDocumentFileInfo,
+ type KnowledgeCreateDocumentResponse,
+} from '@/tools/knowledge/types'
 import { enrichKBTagsSchema } from '@/tools/schema-enrichers'
 import { formatDocumentTagsForAPI, parseDocumentTags } from '@/tools/shared/tags'
 import type { ToolConfig } from '@/tools/types'
@@ -63,30 +66,36 @@ export const knowledgeCreateDocumentTool: ToolConfig<any, KnowledgeCreateDocumen
  if (!textContent || textContent.length < 1) {
  throw new Error('Document content cannot be empty')
  }
- if (textContent.length > 1000000) {
+ const utf8Bytes = new TextEncoder().encode(textContent)
+ const contentBytes = utf8Bytes.length
+
+ if (contentBytes > 1_000_000) {
  throw new Error('Document content exceeds maximum size of 1MB')
  }
 
- const contentBytes = new TextEncoder().encode(textContent).length
-
- const utf8Bytes = new TextEncoder().encode(textContent)
- const base64Content =
- typeof Buffer !== 'undefined'
- ? Buffer.from(textContent, 'utf8').toString('base64')
- : btoa(String.fromCharCode(...utf8Bytes))
+ let base64Content: string
+ if (typeof Buffer !== 'undefined') {
+ base64Content = Buffer.from(textContent, 'utf8').toString('base64')
+ } else {
+ let binary = ''
+ for (let i = 0; i < utf8Bytes.length; i++) {
+ binary += String.fromCharCode(utf8Bytes[i])
+ }
+ base64Content = btoa(binary)
+ }
 
- const dataUri = `data:text/plain;base64,${base64Content}`
+ const { filename, mimeType } = inferDocumentFileInfo(documentName)
+ const dataUri = `data:${mimeType};base64,${base64Content}`
 
- // Parse document tags from various formats (object, array, JSON string)
  const parsedTags = parseDocumentTags(params.documentTags)
  const tagData = formatDocumentTagsForAPI(parsedTags)
 
  const documents = [
  {
- filename: documentName.endsWith('.txt') ? documentName : `${documentName}.txt`,
+ filename,
  fileUrl: dataUri,
  fileSize: contentBytes,
- mimeType: 'text/plain',
+ mimeType,
  ...tagData,
  },
  ]

apps/sim/tools/knowledge/types.ts

@@ -1,3 +1,38 @@
+import {
+ getFileExtension,
+ getMimeTypeFromExtension as getUploadMimeType,
+} from '@/lib/uploads/utils/file-utils'
+
+const TEXT_COMPATIBLE_MIME_TYPES = new Set([
+ 'text/plain',
+ 'text/html',
+ 'text/markdown',
+ 'text/csv',
+ 'application/json',
+ 'application/xml',
+ 'application/x-yaml',
+])
+
+/**
+ * Extracts extension from a filename and returns the normalized filename and MIME type.
+ * If the extension maps to a recognized text-compatible MIME type, it is preserved.
+ * Otherwise, the filename is normalized to `.txt` with `text/plain`.
+ */
+export function inferDocumentFileInfo(documentName: string): {
+ filename: string
+ mimeType: string
+} {
+ const ext = getFileExtension(documentName)
+ if (ext) {
+ const mimeType = getUploadMimeType(ext)
+ if (TEXT_COMPATIBLE_MIME_TYPES.has(mimeType)) {
+ return { filename: documentName, mimeType }
+ }
+ }
+ const base = ext ? documentName.slice(0, documentName.lastIndexOf('.')) : documentName
+ return { filename: `${base || documentName}.txt`, mimeType: 'text/plain' }
+}
+
 export interface KnowledgeSearchResult {
  documentId: string
  documentName: string

apps/sim/tools/knowledge/upsert_document.ts

@@ -1,6 +1,7 @@
-import type {
- KnowledgeUpsertDocumentParams,
- KnowledgeUpsertDocumentResponse,
+import {
+ inferDocumentFileInfo,
+ type KnowledgeUpsertDocumentParams,
+ type KnowledgeUpsertDocumentResponse,
 } from '@/tools/knowledge/types'
 import { enrichKBTagsSchema } from '@/tools/schema-enrichers'
 import { formatDocumentTagsForAPI, parseDocumentTags } from '@/tools/shared/tags'
@@ -94,18 +95,17 @@ export const knowledgeUpsertDocumentTool: ToolConfig<
  base64Content = btoa(binary)
  }
 
- const dataUri = `data:text/plain;base64,${base64Content}`
+ const { filename, mimeType } = inferDocumentFileInfo(documentName)
+ const dataUri = `data:${mimeType};base64,${base64Content}`
 
  const parsedTags = parseDocumentTags(params.documentTags)
  const tagData = formatDocumentTagsForAPI(parsedTags)
 
- const filename = documentName.endsWith('.txt') ? documentName : `${documentName}.txt`
-
  const requestBody: Record<string, unknown> = {
  filename,
  fileUrl: dataUri,
  fileSize: contentBytes,
- mimeType: 'text/plain',
+ mimeType,
  ...tagData,
  processingOptions: {
  chunkSize: 1024,