deepseek-ai/deepseek-harness · error

session "${session.id}": fallback title update failed: ${Str

Error message

session "${session.id}": fallback title update failed: ${String(error)}

What it means

Error "session "${session.id}": fallback title update failed: ${String(error)}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/session/session-title/src/index.ts:484

    // A user rename pins the title: no automatic revision may override it.
    if (this.get(session)?.source.kind === 'user') return
    const registration = this.registration
    if (registration !== undefined && !registration.closing) {
      const messages = collectSessionTitleMessages(session.events, event.seq)
      const shouldSchedule = registration.provider.automatic === 'all-prompts'
        || (session.header.parentSession === undefined && messages.length === 1 && this.get(session) === undefined)
      if (shouldSchedule) {
        const state = this.stateFor(session)
        const revision = this.supersede(state, 'newer user message superseded title generation')
        state.pending = { registration, revision, throughSeq: event.seq }
      }
    }
    this.defer(async () => {
      try {
        await this.ensureFallback(session)
      } catch (error: unknown) {
        if (!this.serviceActive()) return
        this.ctx.logger.warn(`session "${session.id}": fallback title update failed: ${String(error)}`)
      }
    })
  }

  /** Start pending automatic work only after its exact main-request route is logged. */
  private onRequestHeader(session: Session, event: Extract<SessionEvent, { type: 'request/header' }>): void {
    if (!this.serviceActive()) return
    const state = this.work.get(session)
    const pending = state?.pending
    if (state === undefined || pending === undefined || pending.throughSeq >= event.seq) return
    const route = {
      provider: event.data.header.config.provider,
      model: event.data.header.config.model,
    }
    this.startPending(session, state, pending, route)
  }

  /** Start unchanged-route work from the marked loop request after its header fold is current. */

View on GitHub (pinned to b150a551b8)

Solutions

1. Inspect the embedded error from the fallback title update; fix the persistence write it names.

When it happens

Trigger: Thrown at packages/session/session-title/src/index.ts:484 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/91cd5c089b8326cb. Report an issue: GitHub.