Interactive demo does not work with feature "Filter Observations by Tool Calls and add Tool Calls to Dashboard Widgets"

[zdjiangfdu]

Describe your question

Interactive demo uses Vercel AI SDK, but its traces does not contain "tool call" tags of "columns“ . Does the new feature not work with MCP?

Langfuse Cloud or Self-Hosted?

Langfuse Cloud

If Self-Hosted

No response

If Langfuse Cloud

No response

SDK and integration versions

vercel ai sdk of interactive demo

Pre-Submission Checklist

• I have checked for existing issues/discussions and consulted Langfuse AI.

[inkeep-ai-assistant[bot]]

The tool calls filtering and visualization feature works with the Vercel AI SDK, but only for traces ingested after the feature was released(1). The feature supports parsing tool calls from specific frameworks, including the Vercel AI SDK(1).

For tool call data to appear in Langfuse, you need to enable telemetry in your Vercel AI SDK calls by passing experimental_telemetry: { isEnabled: true } to your AI SDK functions(2). The Vercel AI SDK will automatically create telemetry spans for tool calls, which the LangfuseSpanProcessor captures and sends to Langfuse(2).

Regarding MCP (Model Context Protocol), the documentation doesn't mention any specific limitations or incompatibilities with the tool calls feature. However, the feature note states: "this feature only works with traces ingested from now on and does not apply to historical data"(1).

If the interactive demo traces don't show tool call columns, it could be because:

• The traces were created before the feature was released (December 22, 2025)
• Telemetry wasn't properly enabled in the demo's Vercel AI SDK configuration
• The demo needs to be updated to include the proper telemetry setup

To add the tool call columns to your observations table, click on "Columns" and add "Available Tools" and "Tool Calls" to your table view if they're not visible(1).

📚 Sources:

1. Filter Observations by Tool Calls and add Tool Calls to Dashboard Widgets - Langfuse
2. Observability and Tracing for the Vercel AI SDK

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