[BUG] otelHeadersHelper missing in Desktop App

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When using AWS Bedrock as the provider in Cowork 3P (Claude Desktop's third-party provider mode), the otelHeadersHelper used by Claude Code to attach user/session identity to OpenTelemetry traces is not available. This means telemetry sent to a custom OTEL collector endpoint lacks the information needed to attribute requests to specific users on the dashboard.

Context

• Provider: AWS Bedrock via SSO / Identity Center
• Feature: Cowork 3P (third-party model provider support in Claude Desktop)
• OTEL setup: Custom collector endpoint configured in Claude Desktop settings (e.g., https://claude-telemetry.example.io) using http/protobuf exporter protocol

What Should Happen?

When Cowork 3P is configured with a Bedrock provider and an OTEL collector endpoint, the telemetry headers should include user/session identity information — similar to how otelHeadersHelper works in Claude Code — so that dashboard operators can see which user originated each request.

Suggested Approach

• Expose the same (or equivalent) otelHeadersHelper functionality that Claude Code uses to Cowork 3P's telemetry pipeline.
• For Bedrock + SSO, the identity could be derived from the SSO session (e.g., the IAM Identity Center user principal).

Environment

• Claude Desktop with Cowork 3P enabled
• AWS Bedrock provider with SSO / Identity Center authentication
• OpenTelemetry exporter: http/protobuf

Error Messages/Logs

Steps to Reproduce

n/a

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude 1.4758.0 (fb266c) 2026-04-24T20:22:30.000Z

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_