This skill should be used when the user asks to "write LLMObs tests", "add tests for LLM Observability", "test an LLMObs plugin", "llmobs test", "llmobs spec", "test llm observability", "assertLlmObsSpanEvent", "useLlmObs", "getEvents", "MOCK_STRING", "MOCK_NOT_NULLISH", "MOCK_NUMBER", "MOCK_OBJECT", "VCR cassette", "record cassette", "replay cassette", "vcr proxy", "llmobs cassette", "test chat completions", "test streaming", "test embeddings", "test agent runs", "test orchestration", "test workflow", "llmobs span event", "LLMObs test strategy", "LlmObsCategory test", "LLM_CLIENT test", "MULTI_PROVIDER test", "ORCHESTRATION test", "INFRASTRUCTURE test", "span kind llm test", "span kind workflow test", "inputMessages", "outputMessages", "token metrics", "llmobs span validation", "cassette not generated", "re-record cassette", "127.0.0.1:9126", or needs to write, modify, or debug tests for any LLMObs plugin in dd-trace-js.