tools/metrics/histograms/metadata/ai/histograms.xml

<!--
Copyright 2024 The Chromium Authors
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<!--
This file is used to generate a comprehensive list of AI histograms
along with a detailed description for each histogram.

For best practices on writing histogram descriptions, see
https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histograms/README.md

Please follow the instructions in the OWNERS file in this directory to find a
reviewer. If no OWNERS file exists, please consider signing up at
go/reviewing-metrics (Googlers only), as all subdirectories are expected to
have an OWNERS file. As a last resort you can send the CL to
chromium-metrics-reviews@google.com.
-->

<histogram-configuration>

<histograms>

<!-- LINT.IfChange(SessionType) -->

<variants name="SessionType">
  <variant name="LanguageDetector" summary="AI language detector session"/>
  <variant name="LanguageModel" summary="AI language model session"/>
  <variant name="Proofreader" summary="AI proofreader session"/>
  <variant name="Rewriter" summary="AI rewriter session"/>
  <variant name="Summarizer" summary="AI summarizer session"/>
  <variant name="Translator" summary="AI translator session"/>
  <variant name="Writer" summary="AI writer session"/>
</variants>

<!-- LINT.ThenChange(//third_party/blink/renderer/modules/ai/ai_metrics.h:AISessionType) -->

<variants name="WritingAssistanceFunctionName">
  <variant name="availability" summary="Check availability of the model."/>
  <variant name="create" summary="Create a session."/>
</variants>

<variants name="WritingAssistanceType">
  <variant name="Rewriter" summary="AI rewriter session"/>
  <variant name="Summarizer" summary="AI summarizer session"/>
  <variant name="Writer" summary="AI writer session"/>
</variants>

<histogram name="AI.Session.{SessionType}.PromptRequestSize" units="bytes"
    expires_after="2025-10-27">
  <owner>leimy@chromium.org</owner>
  <owner>fergal@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Measures the size of the prompt request in bytes. This is recorded each time
    when the model is executed.
  </summary>
  <token key="SessionType" variants="SessionType"/>
</histogram>

<histogram name="AI.Session.{SessionType}.PromptResponseCallbackCount"
    units="times" expires_after="2025-10-27">
  <owner>leimy@chromium.org</owner>
  <owner>fergal@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Measures the number of times that the callback is triggered in one prompt
    request. This is recorded each time when the model execution completes.
  </summary>
  <token key="SessionType" variants="SessionType"/>
</histogram>

<histogram name="AI.Session.{SessionType}.PromptResponseSize" units="bytes"
    expires_after="2025-10-27">
  <owner>leimy@chromium.org</owner>
  <owner>fergal@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Measures the size of the prompt response in bytes. This is recorded each
    time when the model execution completes.
  </summary>
  <token key="SessionType" variants="SessionType"/>
</histogram>

<histogram name="AI.Session.{SessionType}.PromptResponseStatus"
    enum="AIModelStreamingResponseStatus" expires_after="2025-10-27">
  <owner>leimy@chromium.org</owner>
  <owner>fergal@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Records the final response status for each prompt request. This is recorded
    each time when the stream completes or encounters errors.
  </summary>
  <token key="SessionType" variants="SessionType"/>
</histogram>

<histogram
    name="AI.Summarizer.APIUsage.{WritingAssistanceFunctionName}.CoreOptionType"
    enum="WritingAssistanceMetricsOptionType" expires_after="2025-10-27">
  <owner>btriebw@chromium.org</owner>
  <owner>ayui@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    This is recorded each time when the WritingAssistance function is invoked.
    It can be used to measure the usage of the `type` option.
  </summary>
  <token key="WritingAssistanceFunctionName"
      variants="WritingAssistanceFunctionName"/>
</histogram>

<histogram name="AI.Translation.LoadTranslateKitErrorCode"
    enum="WinGetLastError" expires_after="2025-10-27">
  <owner>mych@google.com</owner>
  <owner>fergal@google.com</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Records the error code of a failed attempt to load the TranslateKit binary
    for on-device translation. It may happen when browser tries to initialize
    the OnDeviceTranslationService. This is only logged on Windows. See
    on_device_translation::TranslateKitClient for more details.
  </summary>
</histogram>

<histogram name="AI.Translation.LoadTranslateKitResult"
    enum="LoadTranslateKitResult" expires_after="2025-10-27">
  <owner>mych@google.com</owner>
  <owner>fergal@google.com</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Records the result of an attempt to load the TranslateKit binary for
    on-device translation. It is logged when browser tries to initialize the
    OnDeviceTranslationService. See on_device_translation::TranslateKitClient
    for more details.
  </summary>
</histogram>

<histogram name="AI.{SessionType}.APIUsage" enum="AIAPI"
    expires_after="2025-10-27">
  <owner>leimy@chromium.org</owner>
  <owner>fergal@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    This is recorded each time when the prompt JavaScript API is invoked. This
    can be used to measure the number of calls of each API within a particular
    time period.
  </summary>
  <token key="SessionType" variants="SessionType"/>
</histogram>

<histogram name="AI.{SessionType}.AvailabilityV2" enum="Availability"
    expires_after="2025-10-27">
  <owner>leimy@chromium.org</owner>
  <owner>fergal@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    Records the availability of model execution as returned in methods like
    `LanguageModel.availability()`.
  </summary>
  <token key="SessionType" variants="SessionType"/>
</histogram>

<histogram
    name="AI.{WritingAssistanceType}.APIUsage.{WritingAssistanceFunctionName}.CoreOptionFormat"
    enum="WritingAssistanceMetricsOptionFormat" expires_after="2025-10-27">
  <owner>btriebw@chromium.org</owner>
  <owner>ayui@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    This is recorded each time when the WritingAssistance function is invoked.
    It can be used to measure the usage of the `format` option.
  </summary>
  <token key="WritingAssistanceType" variants="WritingAssistanceType"/>
  <token key="WritingAssistanceFunctionName"
      variants="WritingAssistanceFunctionName"/>
</histogram>

<histogram
    name="AI.{WritingAssistanceType}.APIUsage.{WritingAssistanceFunctionName}.CoreOptionLength"
    enum="WritingAssistanceMetricsOptionLength" expires_after="2025-10-27">
  <owner>btriebw@chromium.org</owner>
  <owner>ayui@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    This is recorded each time when the WritingAssistance function is invoked.
    It can be used to measure the usage of the `length` option.
  </summary>
  <token key="WritingAssistanceType" variants="WritingAssistanceType"/>
  <token key="WritingAssistanceFunctionName"
      variants="WritingAssistanceFunctionName"/>
</histogram>

<histogram
    name="AI.{WritingAssistanceType}.APIUsage.{WritingAssistanceFunctionName}.CoreOptionTone"
    enum="WritingAssistanceMetricsOptionTone" expires_after="2025-10-27">
  <owner>btriebw@chromium.org</owner>
  <owner>ayui@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    This is recorded each time when the WritingAssistance function is invoked.
    It can be used to measure the usage of the `tone` option.
  </summary>
  <token key="WritingAssistanceType" variants="WritingAssistanceType"/>
  <token key="WritingAssistanceFunctionName"
      variants="WritingAssistanceFunctionName"/>
</histogram>

<histogram
    name="AI.{WritingAssistanceType}.APIUsage.{WritingAssistanceFunctionName}.{LanguageMetric}"
    enum="LocaleCodeBCP47" expires_after="2025-10-27">
  <owner>btriebw@chromium.org</owner>
  <owner>ayui@chromium.org</owner>
  <owner>src/chrome/browser/ai/OWNERS</owner>
  <summary>
    This is recorded each time when the WritingAssistance function is invoked.
    It can be used to measure the usage of the language options.
  </summary>
  <token key="WritingAssistanceType" variants="WritingAssistanceType"/>
  <token key="WritingAssistanceFunctionName"
      variants="WritingAssistanceFunctionName"/>
  <token key="LanguageMetric">
    <variant name="ExpectedContextLanguage"
        summary="Expected context language specified."/>
    <variant name="ExpectedInputLanguage"
        summary="Expected input language specified."/>
    <variant name="OutputLanguage" summary="Output language specified."/>
  </token>
</histogram>

</histograms>

</histogram-configuration>