deepseek-ai/deepseek-harness · error · Error

session event "${event.type}" is not surface-eligible and ca

Error message

session event "${event.type}" is not surface-eligible and cannot carry surfaceOp

What it means

Error "session event "${event.type}" is not surface-eligible and cannot carry surfaceOp" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/core/session/src/surface.ts:189

/** Whether a runtime value is the exact positional-replacement shape. */
function isReplaceOp(value: object): value is Extract<SurfaceOp, { op: 'replace' }> {
  const op = value as Record<string, unknown>
  return Object.keys(op).length === 3
    && Object.hasOwn(op, 'op')
    && Object.hasOwn(op, 'start')
    && Object.hasOwn(op, 'end')
    && op['op'] === 'replace'
    && isEventSeq(op['start'])
    && isEventSeq(op['end'])
}

/** Validate event-local surface eligibility and return its operation. */
function surfaceOpOf(event: SessionEvent): SurfaceOp | undefined {
  const raw = event as SessionEvent & { surfaceOp?: unknown; sourceEventSeqs?: unknown }
  if (!isSurfaceEligibleType(event.type)) {
    if (raw.surfaceOp !== undefined) {
      throw new Error(`session event "${event.type}" is not surface-eligible and cannot carry surfaceOp`)
    }
    if (raw.sourceEventSeqs !== undefined) {
      throw new Error(`session event "${event.type}" is not surface-eligible and cannot carry sourceEventSeqs`)
    }
    return
  }
  const op = raw.surfaceOp
  if (op === undefined) {
    throw new Error(`session event "${event.type}" is surface-eligible and requires a surfaceOp marker`)
  }
  if (op === 'append') return op
  if (op === null || typeof op !== 'object' || Array.isArray(op)) {
    throw new Error(`session event "${event.type}" carries an invalid surfaceOp`)
  }
  if (!isReplaceOp(op)) {
    throw new Error(`session event "${event.type}" carries an invalid replace surfaceOp`)
  }
  return op

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/core/session/src/surface.ts:189 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/0dc2bf79097e739a. Report an issue: GitHub.