deepseek-ai/deepseek-harness · error · WebError

WEB_UNSUPPORTED_CONTENT_TYPE

WEB_UNSUPPORTED_CONTENT_TYPE

Error message

unsupported content type "${contentType ?? 'unknown'}"

What it means

Error "unsupported content type "${contentType ?? 'unknown'}"" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/web/web-fetch-http/src/provider.ts:122

    try {
      return await fetch(url, {
        method: 'GET',
        redirect: 'manual',
        headers: { 'user-agent': this.limits.userAgent, 'accept': 'text/html,application/xhtml+xml,text/*;q=0.9,application/json;q=0.8' },
        signal,
      })
    } catch (error: unknown) {
      throw translateAbortOrNetwork(error, signal)
    }
  }

  /** Read, byte-cap, classify, and decode the final response body. */
  private async readBody(response: Response, finalUrl: URL, signal: AbortSignal): Promise<WebFetchResult> {
    const contentType = response.headers.get('content-type')
    const kind = classifyContentType(contentType)
    if (kind === undefined) {
      await response.body?.cancel()
      throw new WebError(`unsupported content type "${contentType ?? 'unknown'}"`, 'WEB_UNSUPPORTED_CONTENT_TYPE')
    }

    // Resolve the decoder BEFORE reading the body so an unsupported charset
    // fails without consuming the stream — but cancel the body on that failure
    // so the socket does not leak (matching the unsupported-content-type path).
    let decoder: TextDecoder
    try {
      decoder = decoderForCharset(parseCharset(contentType))
    } catch (error: unknown) {
      await response.body?.cancel()
      throw error
    }
    const { bytes, truncatedByBytes } = await this.readCapped(response, signal)
    const decoded = decoder.decode(bytes)
    const truncatedByChars = decoded.length > this.limits.maxBodyChars
    const content = truncatedByChars ? decoded.slice(0, this.limits.maxBodyChars) : decoded
    const body: WebFetchBody = kind === 'html' ? { kind: 'html', content } : { kind: 'text', content }

View on GitHub (pinned to b150a551b8)

Solutions

1. Fetch a resource with a supported content type, or add the content type to the supported list.

When it happens

Trigger: Thrown at packages/web/web-fetch-http/src/provider.ts:122 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/617783fe1f024b95. Report an issue: GitHub.