Quick correction: the link to the explainer in my previous email was broken. The correct link is: https://github.com/webmachinelearning/prompt-api#configuration-of-sampling-modes .
On Friday, August 21, 2026 at 10:06:28 AM UTC-7 Isaac Ahouma wrote: > Hi Mike, > > Thanks for checking in! Here is a quick update on where we stand across > those areas: > > Milestones: > As noted in the intent, we are looking to extend the experiment through > Chrome 159. This aligns with the standard extension policy and gives > developers sufficient time to test the updated categorical presets. > > Draft Spec & TAG Review: > The draft specification <https://webmachinelearning.github.io/prompt-api/> > and explainer <http://LanguageModelSamplingMode> have been updated to > reflect the new AILanguageModelSamplingMode enum structure. TAG review is > currently pending. > > Outreach for feedback & Signals: > While official vendor signals are still pending, we've gathered helpful > qualitative feedback from the community. This input surfaced the large gaps > in our initial presets, which directly motivated this update. > > On the quantitative side, our latest developer survey data shows: > > - 45.8% of developers actively tune parameters (vs. 39.2% who rely on > defaults). > - Among those who tune parameters, 54.5% are favorable to using > semantic presets, while 24.5% prefer raw parameter access. > > Note that this demand for tuning largely reflects broader developer habits > across LLMs in general, rather than Built-in AI specifically. If we need > even more signal during this extension, we plan to tap into > WEC/partnerships or reach out to the EPP mailing list. > > WPT tests & Eval framework: > Web Platform Tests currently cover the API shape and surface. However, for > evaluating the actual model outputs (the effects of sampling parameters), > our ultimate destination is the work in progress with other browser vendors > on shared use-case benchmarks. We are using Web AI Studio as an initial > stepping stone toward that broader evaluation framework. > > Let me know if you need any additional details! > > Cheers, > Isaac > > On Thu, Aug 20, 2026 at 10:18 AM Mike Taylor <[email protected]> wrote: > >> Hi there, >> >> Can you clarify what milestones you are looking to experiment on, and any >> progress on the following since the initial experiment? >> >> Draft spec >> TAG review >> Signals requests >> Outreach for feedback from the spec community >> WPT tests (or some kind of open eval framework) >> >> thanks, >> Mike >> On 8/19/26 12:37 p.m., 'Isaac Ahouma' via blink-dev wrote: >> >> *Contact emails *[email protected], [email protected] >> >> Explainer >> https://github.com/webmachinelearning/prompt-api#sampling-parameters >> >> Specification https://webmachinelearning.github.io/prompt-api/ >> >> Summary The Prompt API Sampling Parameters allow developers to control >> the output variety of the built-in AI language model. Instead of exposing >> raw numerical parameters (e.g. topK and temperature) which can behave >> inconsistently across different underlying model families and versions, >> this feature introduces a categorical samplingMode enum. This allows the >> browser to handle the heavy lifting of mapping semantic presets to optimal >> raw parameters for a specific underlying model, providing developers with >> the necessary granularity to tune responses while maintaining cross-browser >> interoperability. enum AILanguageModelSamplingMode { "most-predictable", >> // For strict consistency/factual extraction "predictable", >> // For highly focused outputs "slightly-predictable", // For >> moderately focused, consistent outputs "balanced", // The >> default state for standard prompting "slightly-creative", // For >> moderately varied, expressive outputs "creative", // For >> tasks favoring variety over strict facts "most-creative" // >> For maximum token diversity and brainstorming }; >> >> Blink component Blink>AI>Prompt >> >> Web Feature ID https://webstatus.dev/features/languagemodel >> >> TAG review status Pending >> >> Link to previous “Intent to Experiment” blink-dev discussion >> https://groups.google.com/a/chromium.org/g/blink-dev/c/4KvH5XEBYtE >> >> Goals for experimentation Our primary goal during this extension is to >> gather real-world usage data on the newly expanded categorical presets to >> see which modes developers gravitate toward most. We will use this data and >> developer feedback to conduct more concerted medium-term mode evaluations. >> Specifically, we want to evaluate developer adoption of this expanded >> spectrum, and validate that the new granularity effectively covers the >> previously identified dead zones. >> >> Experimental timeline The extended experiment will continue through >> Chrome 159. >> >> Reason this experiment is being extended We are extending this >> experiment because we are actively iterating on the API surface based on >> developer feedback. During this trial, we received developer feedback >> requesting predictable space granularity to cover dead zones while >> restoring the balanced preset to the API default parameters. We have >> expanded the preset enum values to cover these dead zones, and we need the >> extended timeline to give developers sufficient time to integrate and test >> these specific changes. >> >> Interoperability and Compatibility Risks The original raw parameters >> were excluded from the initial Prompt API launch due to cross-browser >> interoperability concerns. By refining the categorical sampling modes to >> provide better coverage of the predictable space based on developer >> feedback, we maintain the cross-browser interoperability benefits of >> semantic presets while offering the necessary granularity developers >> requested. WebView application risks None >> >> Ongoing technical constraints None Debuggability It is possible that >> giving DevTools more insight into the nondeterministic states of the model, >> e.g. random seeds, could help with debugging. See related discussion at >> https://github.com/webmachinelearning/prompt-api/issues/9. >> >> Will this feature be supported on all six Blink platforms (Windows, Mac, >> Linux, ChromeOS, Android, and Android WebView)? No, the Prompt API >> currently supports Windows, Mac, Linux, and ChromeOS. >> >> Is this feature fully tested by web-platform-tests? No; while the API >> shape is fully tested, automated testing of sampling parameter effects on >> probabilistic model response is not readily feasible; instead we conduct >> rounds of evaluations on configuration updates. >> >> Flag name on about://flags prompt-api-sampling-mode >> >> Finch feature name AIPromptAPIParams >> >> Requires code in //chrome? True >> >> Tracking bug https://crbug.com/502214118 >> >> Launch bug https://launch.corp.google.com/launch/4463387 Link to entry >> on the Chrome Platform Status: >> https://chromestatus.com/feature/6325545693478912 >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFk4SLZXUY8FQTQQrtLHkzLnkxkgJ7XXFBhDEAQSvy6XiYKgaQ%40mail.gmail.com >> >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFk4SLZXUY8FQTQQrtLHkzLnkxkgJ7XXFBhDEAQSvy6XiYKgaQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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