Files
Kristopher Overholt 50f7df7f46 Add Kotlin language support to ADK docs (#1768)
* Add Kotlin to hero / front page

* Add quickstart page for Kotlin

* Complete Kotlin quickstart guide and fix hero code sample (#2)

* Replace GitHub repo links with language icons in header (#3)

* Fix header icon FOUC and homepage font weight regression (#4)

* Testing staging pipeline

* Revert test edit (for staging pipeline)

* Update language icon tooltips to indicate GitHub destination (#5)

* Add link to ADK Kotlin release notes (#7)

* Initial commit of ADK Kotlin API reference docs (#6)

* Add script to generate ADK Kotlin API reference docs (#8)

* Update links and link checker ignore list (temporarily) (#9)

* Add ADK Kotlin for Android getting started guide to Advanced setup page (#10)

* Add advanced setup page with steps to "Use ADK Kotlin in Android projects"

* Update temp link checker rules

* Add placeholder folder for adk-samples (#13)

* adding linter/compilation checks for kotlin snippets (#12)

* adding linter/compilation checks for kotlin snippets

* Add Kotlin validation scripts

* Initial commit of Kotlin sample agents for adk-samples (#15)

* Adding kotlin snippet for llm agents (#16)

* Adding kotlin snippets to  Events (#17)

* Pull changes to docs/events/index.md from glaforge-kotlin-snippets

* fixing kotlin event timestamp and longRunningToolIds

* Fix language tags (#19)

* Fix language tags

* Update

* Fix wrapping

* Fix wrapping (again)

* Fix wrapping/format

* Fix language tag on integration page

* Enable check_paths in PyMdown Snippets Extension to make the build fail if a snippet can't be found (#20)

* Update mkdocs config (#21)

* Fix broken links, update URLs to adk.dev, and improve (temp) lychee config (#22)

* Add Kotlin/maven badge to README (#23)

* Adding Kotlin snippets for artifacts  (#18)

* Pull Kotlin snippets for artifacts from glaforge-kotlin-snippets

* Add comprehensive Kotlin snippets for artifacts

* Refactor artifacts documentation to use external Kotlin snippets

* Update Kotlin model to gemini-flash-latest

* Fix GCS initialization in Kotlin artifact snippet

* afixi failing test with capital-agent added to files_to_check

* Fix snippet label syntax for MkDocs build

* Configure proper Gradle project for Kotlin snippets and fix dependencies

* Add KSP support and generated sources to Kotlin snippets build

* fixing capital_agent turnComplete

* Fix syntax error in build.gradle.kts by removing invalid placeholders (#25)

* Adding Kotlin snippets to google-gemini.md (#27)

Pulling kotlin changes to google-gemini.md from glaforge-kotlin-snippets

* Add a warning about not adding an api key to production code. (#28)

* Add a warning about not adding an api key to production code.

* Update note

---------

Co-authored-by: Kristopher Overholt <koverholt@google.com>

* Add ADK Demo App sample showcasing Gemini-powered agents (#29)

This sample demonstrates how to use the Google ADK (Agent Development Kit) in an Android application to create a chat interface powered by a Gemini-based "Fun Facts" agent. The implementation features:
*   Integration with the Kotlin ADK core and processor libraries.
*   A `FunFactsAgent` defined using `LlmAgent` and the Gemini model.
*   A `ChatViewModel` utilizing `InMemoryRunner` for asynchronous message streaming.
*   A modern UI built with Jetpack Compose and Material 3.
*   Build configuration logic for secure API key management via environment variables or `local.properties`.

* Update Kotlin docs and samples to align with adk-kotlin API changes (#30)

Rename GeminiModel to Gemini, @AdkTool/@AdkParam to @Tool/@Param,
adkTools() to generatedTools(), replace DebugRunner with InMemoryRunner,
fix AgentLoader import path, use SingleAgentLoader, bump Kotlin to
2.3.21 and KSP to 2.3.7, and update Android minSdk from 24 to 26.

* adding kotlin info to READMEs (#14)

* Reorganize Android sample agent and add READMEs (#31)

* Move Android sample agent

* Update repo README, add Android README, update sample agent README

* Minor edit to language support tags (#32)

* Remove blog post link (#33)

Will re-add after it's published

* Remove examples link (#34)

* Adding Kotlin snippets for Sessions docs (#26)

* initial kotlins snippets additions to sessions docs

* Updating memory docs with kotlin snippets

* Adding kotlin snippets to session state docs.

* update model to gemini-flash-latest

* sessions examples clean-up

* fixing sessions snippet markers

* adding kotlin session snippets to files to test

* adding callback to memory_example

* Fixing capital agent snippet  (#35)

Fixing file name
Updating adkTool > Tool
Updating GeminiModel > Gemini

* Adding kotlin snippets for tools docs (#36)

* adding function tool kotlin snippets

* adding function_tools snippets to files to test

* Adding kotlin snippets to observability docs (#37)

* initial kotlin observability updates

* adding observability snippets to file check (#38)

* Adding Kotlin snippets to Callbacks docs (#39)

*  kotlin callbacks snippets

* adding callbacks snippets to file check

* Align Kotlin and KSP versions with published 0.1.0 artifacts (#40)

* switch CLI entry points from InMemoryRunner to ReplRunner (#41)

* Switch CLI entry points from InMemoryRunner to ReplRunner

* Fix wording

* Update API reference docs for Kotlin, 2026-05-18 (#42)

* Remove ADK on Android note until published (#43)

* Update Kotlin code samples (#44)

* Rename GeminiModel to Gemini in Kotlin snippets and docs

* Remove broken SessionKey call and use sessionId directly in AgentTool snippet

* Rewrite Go hero snippet to use llmagent API

* Use isFinalResponse with safe access in CapitalAgent snippet

* Use Role.USER constant instead of raw string in SetupExample

* Use full semver v0.1.0 in Kotlin language support tags

* Remove Android setup steps, moving to new property (#45)

* Tutorial Kotlin agent (#46)

* Adding multi-tool-agent snippet and updating tutorial
* Fixing Go language order on tutorial page
* adding multi tool agent example to files to test

* Inline Kotlin get-started code sample

* Kotlin Multi agents snippets (#47)

* Multi-agent kotlin snippets

* Fixing docs tags in multiagent example

* Fix Kotlin language support tags, code samples, and google-gemini.md cleanup (#48)

* Add Kotlin v0.1.0 to language support tags across docs

* Fix MultiToolAgent.kt model string and argument style

* Update MultiAgentExample.kt to use gemini-flash-latest model string

* Fix google-gemini.md: add Kotlin sample, remove unsupported Java tabs

* Remove explicit apiKey from CallbackBasic.kt for consistency

* Standardize Gemini() constructor to use named args in all snippets

* Remove adk-samples directory (moved to google/adk-samples#1969)

* Remove adk-samples directory (moved to google/adk-samples#1969) (#49)

* Update API reference docs for ADK Kotlin 0.1.0 (#50)

* Remove adk-samples directory (moved to google/adk-samples#1969)

* Update API reference docs for ADK Kotlin 0.1.0

* Remove kotlin lycheeignore config (#51)

* Remove adk-samples directory (moved to google/adk-samples#1969)

* Remove Kotlin .lycheeignore config links

---------

Co-authored-by: Toni Klopfenstein <2359976+ToniCorinne@users.noreply.github.com>
Co-authored-by: Jolanda Verhoef <JolandaVerhoef@users.noreply.github.com>
2026-05-19 11:43:42 -05:00

5.8 KiB

Agent activity traces

Supported in ADKPython v1.17.0Go v1.0.0Kotlin v0.1.0

Agent Development Kit (ADK) provides distributed tracing capabilities to help you visualize the end-to-end journey of a request as it travels through your agent's architecture. While metrics tell you how long a process took and logs tell you what happened, traces connect these events, showing you exactly where the time was spent and the hierarchical relationship between LLM reasoning, tool calls, and external APIs.

Traces philosophy

ADK's approach to tracing is built on standard protocols to ensure seamless integration with your existing observability stack.

  • OpenTelemetry Semantic Conventions: ADK implements the OpenTelemetry (OTel) Semantic Conventions for GenAI. This ensures that trace spans and attributes are recorded under standard, predictable names.
  • OTLP Wire Format: ADK emits data using the standard OTLP format, ensuring that your traces will seamlessly integrate into any OTel-compatible backend (e.g., Google Cloud Trace, Jaeger, Grafana Tempo, Datadog).
  • Hierarchical Visualization: Traces are organized into "Spans." An agent run is a root span, which contains child spans for LLM operations, which may in turn contain child spans for tool executions. This creates a clear "waterfall" view of the agent's reasoning loop.
  • Context Propagation: ADK automatically passes trace context across process boundaries, ensuring that if your agent calls an external microservice via a tool, that service's spans are linked to the agent's root trace.

Traces schema

When tracing is enabled, ADK automatically instruments key operations following the OpenTelemetry GenAI Semantic Conventions for Agents. A typical trace waterfall includes the following spans:

Span Name Type Description Key Attributes
invoke_agent Client / Internal Span Describes GenAI agent invocation over a remote service or locally. Represents the lifecycle of an agent interaction. gen_ai.agent.name, gen_ai.system
invoke_workflow Child Span Describes the invocation of a multi-step agentic workflow. gen_ai.workflow.name, gen_ai.system
execute_tool Child Span Represents the execution of a specific tool or function call requested by the GenAI system. gen_ai.tool.name, gen_ai.system
generate_content {model.name} Internal Span Represents the invocation of the underlying language model (via the GenAI SDK) to generate content. It tracks the request parameters, response details, and usage metrics. gen_ai.operation.name, gen_ai.system, gen_ai.request.model, gen_ai.agent.name, gen_ai.conversation.id, user.id, gen_ai.request.top_p, gen_ai.request.max_tokens, gen_ai.response.finish_reasons, gen_ai.usage.input_tokens, gen_ai.usage.output_tokens

Traces export setup

Traces export in ADK Web

If you are running your agent using the adk web or adk api_server CLI commands, you can configure trace exports.

OTLP export

To export traces to an OTLP-compatible backend, set the standard OTel environment variables:

export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT="http://your-collector:4318/v1/traces"
adk web path/to/your/agents_dir

Note: You can also set the general OTEL_EXPORTER_OTLP_ENDPOINT environment variable if you would like to send metrics and logs to the same endpoint in addition to traces.

GCP export

To enable trace export to Google Cloud Trace, use the --otel_to_cloud flag:

adk web --otel_to_cloud path/to/your/agents_dir

Programmatic traces export

You can also configure trace export programmatically in your application code.

OTLP export setup

To enable tracing and export spans to an OpenTelemetry Collector programmatically:

from google.adk.telemetry.setup import maybe_set_otel_providers
import os

os.environ["OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"] = "http://your-collector:4318/v1/traces"
os.environ["OTEL_SERVICE_NAME"] = "your-adk-agent"
os.environ["OTEL_RESOURCE_ATTRIBUTES"] = "key1=value1,key2=value2"
maybe_set_otel_providers()

GCP export setup

To export traces to Google Cloud Trace programmatically, use the OpenTelemetry Google Cloud exporter. Here is an example in Python:

from google.adk.telemetry.google_cloud import get_gcp_exporters
from google.adk.telemetry.setup import maybe_set_otel_providers
import os

gcp_exporters = get_gcp_exporters(
  enable_cloud_tracing = True,
)
os.environ["OTEL_SERVICE_NAME"] = "your-adk-agent"
os.environ["OTEL_RESOURCE_ATTRIBUTES"] = "key1=value1,key2=value2"
maybe_set_otel_providers([gcp_exporters])

Kotlin programmatic setup

In Kotlin, ADK automatically uses the GlobalOpenTelemetry instance to export traces. You should configure your OpenTelemetry SDK before starting the agent.

OTLP export setup

To enable tracing and export spans to an OpenTelemetry Collector, configure the OpenTelemetry SDK and register it globally:

--8<-- "examples/kotlin/snippets/observability/SetupExample.kt:full_example"