deepseek-ai/deepseek-harness · error · LlmError

UNSUPPORTED_CONTENT

UNSUPPORTED_CONTENT

Error message

The DeepSeek chat-completions adapter does not support image content.

What it means

Error "The DeepSeek chat-completions adapter does not support image content." thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/llm/llm-deepseek/src/serialize.ts:110

  if (effort === 'off') return { thinking: 'disabled' }
  if (effort === 'low' || effort === 'high' || effort === 'max') {
    return { thinking: 'enabled', reasoningEffort: effort }
  }
  return defaults.thinking === undefined ? {} : { thinking: defaults.thinking }
}

/** Join the text blocks of a message (used for user/tool-result content). */
function flattenText(blocks: ContentBlock[]): string {
  return blocks
    .filter(block => block.type === 'text')
    .map(block => block.text)
    .join('')
}

/** Reject core image content before any text-flattening path can silently erase it. */
function assertTextOnly(blocks: readonly ContentBlock[]): void {
  if (contentHasImage(blocks)) {
    throw new LlmError('The DeepSeek chat-completions adapter does not support image content.', 'UNSUPPORTED_CONTENT')
  }
}

/** Reject roles whose DeepSeek history format cannot carry image input. */
function assertSupportedImageRoles(messages: readonly Message[]): void {
  for (const message of messages) {
    if (message.role !== 'user' && contentHasImage(message.content)) {
      throw new LlmError(
        `The DeepSeek chat-completions adapter cannot represent image content in a ${message.role} message.`,
        'UNSUPPORTED_CONTENT',
      )
    }
  }
}

/** Describe the exact request preview and its model-callable coordinate system. */
function imageHandle(
  version: RequestImageAttachment,

View on GitHub (pinned to b150a551b8)

Solutions

1. Remove image content from the request or use an adapter/model that accepts images.

When it happens

Trigger: Thrown at packages/llm/llm-deepseek/src/serialize.ts:110 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/44449aa653fe5e27. Report an issue: GitHub.