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LangWatch integrates with Anthropic through OpenInference instrumentation to capture detailed information about your Claude API calls.

Installation

Usage

The LangWatch API key is configured by default via the LANGWATCH_API_KEY environment variable.
Use the OpenInference instrumentation for Anthropic by passing AnthropicInstrumentor to langwatch.setup().
The AnthropicInstrumentor automatically captures all Anthropic API calls globally once instrumented. Use @langwatch.trace() to create a parent trace under which API calls will be nested.

Check it worked

Run the example. Then open your project in LangWatch: a new trace named “Anthropic Call with Community Instrumentor” appears in the traces list within a few seconds. Open it to see the Anthropic call nested inside it, with its input and output. If no trace appears, check that LANGWATCH_API_KEY is set in the environment the script runs in.
Last modified on October 29, 2026