Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/cloudflare

SDK Version

10.3.0

Framework Version

No response

Link to Sentry event

https://ansearch.sentry.io/traces/trace/490b74c4ebdf422880ad494ec5500f27/?end=2025-08-16T01%3A23%3A57&mode=samples&node=span-bca03ce942e255f4&pageEnd=Sat%20Aug%2016%202025%2002%3A23%3A57%20GMT%2B0100%20%28British%20Summer%20Time%29&pageStart=Wed%20Aug%2013%202025%2002%3A23%3A57%20GMT%2B0100%20%28British%20Summer%20Time%29&project=-1&query=trace%3A490b74c4ebdf422880ad494ec5500f27&source=traces&start=2025-08-13T01%3A23%3A57&statsPeriod&table=trace&timestamp=1755178643.709

Reproduction Example/SDK Setup

Nested manual spans as described here: https://docs.sentry.io/platforms/javascript/guides/cloudflare/tracing/span-metrics/#creating-dedicated-metric-spans are not showing up in error traces.

I'm facing some deep issues in my workflows, and using the spans to debug what is happening. To do so, I'm nesting spans (one span for multiple step.do that are related)

The issue is none of those nested span are showing up in the dashboard, making it impossible to track what is going on

Steps to Reproduce

class WorkflowIngestBase extends WorkflowEntrypoint<
  Cloudflare.Env,
  IngestionWorkflowParameters
> {
  async run(
    event: WorkflowEvent<IngestionWorkflowParameters>,
    step: WorkflowStep,
  ): Promise<void> {
    const page = step.do('fetch page'() => {...})

    for (const item in page.item){
      Sentry.startSpan(
        {
          name: 'my custom span',
          attributes: {
            pageID: page.id,
          }
        },
        async () => {
          await step.do('process page item', async () => {...})
          await step.do('save item', async () => {...})
        }
      );
    }
  }
}

export const WorkflowIngest = SentryCloudflare.instrumentWorkflowWithSentry(
  (_environment: Cloudflare.Env) => {
    return {
      dsn: '...',
      ...customSentryConfig,
    };
  },
  WorkflowIngestBase,
);

Expected Result

(in Sentry)

Trace
|- step.do fetch page
|- my custom span
| |- step.do process item
| |- step.do save item
|- my custom span
| |- step.do process item
| |- step.do save item
| ...

Actual Result

(in Sentry)

Trace
|- step.do fetch page
|- step.do process item
|- step.do save item
|- step.do process item
|- step.do save item