METRICS: {
    GEN_AI_CLIENT_OPERATION_DURATION: "gen_ai.client.operation.duration";
    GEN_AI_CLIENT_TOKEN_USAGE: "gen_ai.client.token.usage";
    GEN_AI_SERVER_REQUEST_DURATION: "gen_ai.server.request.duration";
    GEN_AI_SERVER_TIME_TO_FIRST_TOKEN: "gen_ai.server.time_to_first_token";
    GEN_AI_SERVER_TIME_PER_OUTPUT_TOKEN: "gen_ai.server.time_per_output_token";
    AGENT_INVOCATIONS: "adk.agent.invocations";
    TOOL_EXECUTIONS: "adk.tool.executions";
    LLM_CALLS: "adk.llm.calls";
    ERRORS: "adk.errors";
    AGENT_DURATION: "adk.agent.duration";
    TOOL_DURATION: "adk.tool.duration";
    LLM_DURATION: "adk.llm.duration";
    LLM_TOKENS: "adk.llm.tokens";
    LLM_INPUT_TOKENS: "adk.llm.tokens.input";
    LLM_OUTPUT_TOKENS: "adk.llm.tokens.output";
} = ...

Metric names Includes both standard OpenTelemetry GenAI metrics and ADK-specific metrics