Issue Review: cloudflare/workers-sdk#10513

Summary

Structured JSON logs with Error objects appear as empty {} on Cloudflare dashboard despite showing data in local wrangler dev.

Findings

• Created: 2025-09-01
• Updated: 2025-09-02
• Version: Wrangler 4.33.1, Node 22.19.0, macOS 15.6.1
• Component: Cloudflare observability/logging (not workers-sdk)
• Labels: bug
• Comments: 2

Key Evidence

• Not a workers-sdk issue: A Cloudflare team member (@edmundhung) confirmed with the observability team that this is a "limitation in the production runtime when processing error objects" - meaning this is a Cloudflare platform limitation, not a wrangler/workers-sdk bug.
• Reporter accepted workaround: The reporter acknowledged the explanation and stated the workaround (stringifying Error objects) works for them.
• Issue is misplaced: This should be tracked in a Cloudflare platform/observability tracker if it needs to be tracked at all, not in workers-sdk.

Recommendation

Status: CLOSE

Reasoning: This is a confirmed limitation in the Cloudflare production runtime's observability system, not a bug in wrangler or workers-sdk. The Cloudflare team confirmed this, and the reporter has accepted the workaround. The workers-sdk repository is not the correct place for this issue.

Action: Close the issue with a comment explaining this is a platform limitation that has been acknowledged.

Suggested Comment

Closing this issue as it has been confirmed by the observability team that this is a known limitation in the Cloudflare production runtime when processing Error objects in structured logs.

The workaround is to stringify Error objects before passing them to console methods:

console.error('Message', { error: error.message, stack: error.stack });
// or
console.error('Message', { error: JSON.stringify(error) });

If you'd like to see this limitation addressed in the platform, please file feedback through the Cloudflare dashboard or community forums.

Thank you for reporting this!