deepseek-ai/deepseek-harness · error

conversation Context ${key} received non-appended Match ${in

Error message

conversation Context ${key} received non-appended Match ${input.event.seq}

What it means

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

Source

Thrown at packages/client/runtime/src/client/sessions/conversation-assembler.ts:422

        startSeq: undefined,
        start: undefined,
        matches: [],
        state: undefined,
        revision: 0,
        current: new Map(),
        locationData: emptyLocationData(),
        dependencies: new Map(),
      }
      this.contexts.set(key, context)
    }
    const match: ConversationMatch = {
      ...input,
      role,
      location: this.locationIndex.locationOf(input.event),
    }
    const previous = context.matches.at(-1)
    if (previous !== undefined && previous.event.seq >= input.event.seq) {
      throw new Error(`conversation Context ${key} received non-appended Match ${input.event.seq}`)
    }
    if (role === 'start' && context.matches.length > 0) {
      throw new Error(`conversation Context ${key} received an update before its start Match`)
    }
    context.matches.push(match)
    if (role === 'start') {
      context.startSeq = input.event.seq
      context.start = match
      this.indexStartedContext(context)
    }
    const owners = this.contextsBySeq.get(input.event.seq) ?? new Set<InternalContext>()
    owners.add(context)
    this.contextsBySeq.set(input.event.seq, owners)

    if (role === 'start') {
      this.replayContext(context)
    } else if (context.state !== undefined) {
      const typed = contextSnapshot(context) as ConversationNodeContext & { readonly state: unknown }

View on GitHub (pinned to b150a551b8)

Solutions

1. Append events in seq order; do not deliver a non-appended Match.

When it happens

Trigger: Thrown at packages/client/runtime/src/client/sessions/conversation-assembler.ts:422 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/fadc4bfe2813f760. Report an issue: GitHub.