conversation Context ${key} received duplicate Match ${left.

Error message

conversation Context ${key} received duplicate Match ${left.event.seq}

What it means

Error "conversation Context ${key} received duplicate Match ${left.event.seq}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/client/runtime/src/client/sessions/conversation-assembler.ts:106

    start: context.start,
    state: context.state as State | undefined,
    current: context.current,
  }
}

function mergeMatches(
  key: string,
  additions: readonly ConversationMatch[],
  existing: readonly ConversationMatch[],
): ConversationMatch[] {
  const merged: ConversationMatch[] = []
  let added = 0
  let current = 0
  while (added < additions.length || current < existing.length) {
    const left = additions[added]
    const right = existing[current]
    if (left !== undefined && right !== undefined && left.event.seq === right.event.seq) {
      throw new Error(`conversation Context ${key} received duplicate Match ${left.event.seq}`)
    }
    if (right === undefined || (left !== undefined && left.event.seq < right.event.seq)) {
      merged.push(left as ConversationMatch)
      added++
    } else {
      merged.push(right)
      current++
    }
  }
  return merged
}

/** Event Registry subset consumed by a Session-owned Assembler. */
export interface ConversationEventDefinitions {
  /** @returns ordinary Definitions in registration order. */
  entries(): readonly ConversationNodeDefinition[]
  /** @returns unmatched-event fallback, when registered. */
  fallbackEntry(): ConversationNodeDefinition | undefined

View on GitHub (pinned to b150a551b8)

Solutions

Fix the event source so a Context does not receive a duplicate Match for the same seq.

When it happens

Trigger: Thrown at packages/client/runtime/src/client/sessions/conversation-assembler.ts:106 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/cd109481693aaaf1. Report an issue: GitHub.