Function readImageWithTokenBudget

src/tools/FileReadTool/FileReadTool.ts:1097–1183

(
  filePath: string,
  maxTokens: number = getDefaultFileReadingLimits().maxTokens,
  maxBytes?: number,
)

 * @returns Image data with appropriate compression applied
 */
export async function readImageWithTokenBudget(
  filePath: string,
  maxTokens: number = getDefaultFileReadingLimits().maxTokens,
  maxBytes?: number,
): Promise<ImageResult> {
  // Read file ONCE — capped to maxBytes to avoid OOM on huge files
  const imageBuffer = await getFsImplementation().readFileBytes(
    filePath,
    maxBytes,
  )
  const originalSize = imageBuffer.length

  if (originalSize === 0) {
    throw new Error(`Image file is empty: ${filePath}`)
  }

  const detectedMediaType = detectImageFormatFromBuffer(imageBuffer)
  const detectedFormat = detectedMediaType.split('/')[1] || 'png'

  // Try standard resize
  let result: ImageResult
  try {
    const resized = await maybeResizeAndDownsampleImageBuffer(
      imageBuffer,
      originalSize,
      detectedFormat,
    )
    result = createImageResponse(
      resized.buffer,
      resized.mediaType,
      originalSize,
      resized.dimensions,
    )
  } catch (e) {
    if (e instanceof ImageResizeError) throw e
    logError(e)
    result = createImageResponse(imageBuffer, detectedFormat, originalSize)
  }

  // Check if it fits in token budget
  const estimatedTokens = Math.ceil(result.file.base64.length * 0.125)
  if (estimatedTokens > maxTokens) {
    // Aggressive compression from the SAME buffer (no re-read)
    try {
      const compressed = await compressImageBufferWithTokenLimit(
        imageBuffer,
        maxTokens,
        detectedMediaType,
      )
      return {
        type: 'image',
        file: {
          base64: compressed.base64,
          type: compressed.mediaType,
          originalSize,
        },
      }
    } catch (e) {