Add cross workspace tracing

[victorm-lc]

Overview

Adding context on how to dynamically route traces to different LangSmith workspaces at runtime. This includes documentation for generic cross-workspace tracing in applications and overriding the default workspace for LangSmith deployments.

Type of change

Type: Update existing documentation

Related issues/PRs

• GitHub issue: N/A
• Feature PR: N/A

• Linear issue:
• Slack thread: https://langchain.slack.com/archives/C089RDWTKU4/p1760470955955709

Checklist

• I have read the contributing guidelines
• I have tested my changes locally using docs dev
• All code examples have been tested and work correctly
• I have used root relative paths for internal links
• I have updated navigation in src/docs.json if needed

(Internal team members only / optional): Create a preview deployment as necessary using the Create Preview Branch workflow

Additional notes

This PR adds a new section to src/langsmith/log-traces-to-project.mdx titled "Set the destination workspace dynamically" which covers two main use cases:

1. Generic cross-workspace tracing: For applications that need to dynamically route traces to different workspaces based on runtime logic (e.g., customer ID, tenant, environment)
2. Override default workspace for LangSmith deployments: For deployed agents where the default workspace needs to be overridden using graph lifespan context managers

Both Python and TypeScript code examples are provided for each use case, demonstrating the use of tracing_context/withTracing and workspace-specific LangSmith clients.

This documentation is particularly useful for multi-tenant applications that need to isolate traces by customer, environment, or team at the workspace level.

[github-actions]

Mintlify preview ID generated: preview-vicadd-1763428047-befe6c7