Telemetry events for the ADK pipeline.

ADK emits :telemetry events at key execution points so you can attach handlers for logging, metrics, tracing, or anything else.

Events

All events follow the [:adk, <component>, <stage>] convention with :start, :stop, and :exception suffixes (compatible with :telemetry.span/3).

Agent Events — [:adk, :agent, ...]

• [:adk, :agent, :start] — fired when an agent begins execution

  • Measurements: %{monotonic_time: integer(), system_time: integer()}
  • Metadata: %{agent_name: String.t(), session_id: term()}

• [:adk, :agent, :stop] — fired when an agent completes

  • Measurements: %{duration: integer(), monotonic_time: integer()}
  • Metadata: same as start

• [:adk, :agent, :exception] — fired on agent crash

  • Measurements: %{duration: integer(), monotonic_time: integer()}
  • Metadata: same as start + %{kind: atom(), reason: term(), stacktrace: list()}

LLM Events — [:adk, :llm, ...]

• [:adk, :llm, :start] — fired before an LLM call

  • Measurements: %{monotonic_time: integer(), system_time: integer()}
  • Metadata: %{model: String.t(), agent_name: String.t()}

• [:adk, :llm, :stop] — fired after an LLM call completes

  • Measurements: %{duration: integer(), monotonic_time: integer()}
  • Metadata: same as start

• [:adk, :llm, :exception] — fired on LLM call failure

  • Measurements: %{duration: integer(), monotonic_time: integer()}
  • Metadata: same as start + %{kind: atom(), reason: term(), stacktrace: list()}

Tool Events — [:adk, :tool, ...]

• [:adk, :tool, :start] — fired before a tool executes

  • Measurements: %{monotonic_time: integer(), system_time: integer()}
  • Metadata: %{tool_name: String.t(), agent_name: String.t()}

• [:adk, :tool, :stop] — fired after a tool completes

  • Measurements: %{duration: integer(), monotonic_time: integer()}
  • Metadata: same as start

• [:adk, :tool, :exception] — fired on tool crash

  • Measurements: %{duration: integer(), monotonic_time: integer()}
  • Metadata: same as start + %{kind: atom(), reason: term(), stacktrace: list()}

Attaching Handlers

:telemetry.attach_many(
  "my-adk-handler",
  ADK.Telemetry.events(),
  &MyHandler.handle_event/4,
  nil
)

OpenTelemetry Integration

When the full :opentelemetry SDK is loaded, span/3 will additionally create OpenTelemetry spans, bridging :telemetry events into distributed traces. No configuration needed — it auto-detects.