deepseek-ai/deepseek-harness · error · Error

tool/result surface replacement must target a current tool/r

Error message

tool/result surface replacement must target a current tool/result

What it means

Error "tool/result surface replacement must target a current tool/result" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/surface.ts:300

  if (aKeys.length !== Object.keys(b).length) return false
  return aKeys.every(key => Object.hasOwn(b, key) && isDeepEqualJson((a as Record<string, unknown>)[key], bRecord[key]))
}

/** Restrict a tool-result replacement to one current result's content. */
function assertToolResultRewrite(
  event: SessionEvent,
  shadowedSeqs: readonly number[],
  events: readonly SessionEvent[],
  baseSeq: number,
): void {
  if (event.type !== 'tool/result') return
  if (shadowedSeqs.length !== 1) {
    throw new Error('tool/result surface replacement must rewrite exactly one current node')
  }
  for (const originalSeq of shadowedSeqs) {
    const original = events[originalSeq - baseSeq]
    if (original?.type !== 'tool/result') {
      throw new Error('tool/result surface replacement must target a current tool/result')
    }
    const originalRest = { ...original.data } as Record<string, unknown>
    const replacementRest = { ...event.data } as Record<string, unknown>
    const originalResult = original.data.message.content[0]
    const replacementResult = event.data.message.content[0]
    originalRest['message'] = {
      ...original.data.message,
      content: [{ ...originalResult, content: null }],
    }
    replacementRest['message'] = {
      ...event.data.message,
      content: [{ ...replacementResult, content: null }],
    }
    if (!isDeepEqualJson(originalRest, replacementRest)) {
      throw new Error('tool/result surface replacement may change only content')
    }
  }
}

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/core/session/src/surface.ts:300 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/f016f00437e621f4. Report an issue: GitHub.