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MIRA’s document parsing is done entirely in TypeScript inside a Node.js worker_threads worker (src/workers/document-parser.worker.ts). This keeps the main process unblocked during heavy I/O or CPU parsing. Adding a new format means extending this worker.

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How parsers work

When a document is uploaded, src/main/document-parser.ts spawns a Worker from src/workers/document-parser.worker.ts. The worker receives a raw Buffer, detects the format by MIME type and file extension, and posts a ParseResult back: 
// src/workers/document-parser.worker.ts (simplified return shape)
interface ParseResult {
  content: string // Full extracted text
  chunks: DocumentChunk[] // Pre-chunked text slices
  chunkCount: number
  metadata: Record<string, unknown> // Format-specific metadata
}

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1. Add the npm dependency (if needed)

If your format requires a parsing library, add it to package.json: 
npm install my-format-parser
For type definitions: 
npm install -D @types/my-format-parser

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2. Add the parser branch to the worker

In src/workers/document-parser.worker.ts, add a new if branch. The worker uses MIME type first, file extension as fallback: 
// src/workers/document-parser.worker.ts — inside the run() function

// My custom format
if (mimeType === 'application/x-my-format' || ext === 'myext') {
  try {
    const { parseMyFormat } = await import('my-format-parser')
    const result = await parseMyFormat(buffer)
    content = result.text
    metadata.version = result.version
  } catch (e) {
    content = `[my-format parse error: ${e instanceof Error ? e.message : String(e)}]`
  }
}

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3. Register the supported extension

In src/shared/constants.ts, add the extension to SUPPORTED_EXTENSIONS: 
export const SUPPORTED_EXTENSIONS = [
  '.pdf',
  '.docx',
  '.txt',
  '.md',
  '.csv',
  '.json',
  '.py',
  '.js',
  '.ts',
  '.html',
  '.myext', // ← add here
] as const

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4. Add the MIME type mapping

In src/shared/types.ts, add the MIME type to the DocumentMimeType union so TypeScript accepts it: 
export type DocumentMimeType =
  | 'application/pdf'
  | 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
  | 'text/plain'
  // ...existing types
  | 'application/x-my-format' // ← add here
  | string

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5. Add the file extension to the upload dialog filter

In src/main/ipc-handlers.ts, find where skills:open-file-dialog and workflows:open-file-dialog define Electron dialog.showOpenDialog filters, and add your extension to the documents upload filter: 
filters: [
  {
    name: 'Documents',
    extensions: ['pdf', 'docx', 'txt', 'md', 'csv', 'json', 'py', 'js', 'ts', 'html', 'myext'],
  },
]

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6. Update docs

Add your new format to the table in Supported File Formats.
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