Summarizer API isn't working

[sophie]

I'm trying to use the summarize API. I've already followed all the instructions as listed here, but the error continues to pop up. I've restarted as well. In the summarize API diagnostics page, it seems that the count is going up, but it doesn't actually return results. What can / should I do?

[Connie Leung]

Follow the error message and add outputLanguage: ["en"] in Sumarizer.create()

On Fri, 31 Oct 2025, 9:54 am sophie, <sophie...@gmail.com> wrote:

I'm trying to use the summarize API. I've already followed all the instructions as listed here, but the error continues to pop up. I've restarted as well. In the summarize API diagnostics page, it seems that the count is going up, but it doesn't actually return results. What can / should I do?

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[Kenji Baheux]

Hi Sophie,

In the screenshot of your app / extension, I see mentions of window.ai and self.ai.

We have long moved away from this namespace. Our APIs are now directly available as can be seen in the other screenshot where you tried Summarizer.create()

I suspect that the code for your app / extension is using window.ai or self.ai

Please refer to the latest docs: 

https://share.google/bIMtVAZuzIuaGrXQN

Kenji BAHEUX (my how-to)

Product Manager - Chrome

Google Japan

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[Connie Leung]

Sophie,

Good luck in the hackathon.

Connie

To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/chrome-ai-dev-preview-discuss/CADWWn7XQ-T4Q9F%2B5KhmZONKZWmYdbCSow0gxFedToo8nj4iGXA%40mail.gmail.com.

[Connie Leung]

Kenji and Tom,

I mentioned to Andre that people are finding outdated tutorials that use window.ai.X instead of X.create()/X.availability().  It is happening more frequently as the hackathon deadline approaches.  

Connie

[Kenji Baheux]

I wonder if it's online tutorials or LLMs with obsolete knowledge.

Sophie, can you help us understand which it might be?

Are you using an online doc / article, or are you using an LLM / Cloud AI service to vibe code something (which one)?

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[Thomas Steiner]

Since the screenshot shows both, window.ai and also the current implementation like Summarizer.createe(), it may be an attempt at feature-detecting the old and the new API. It looks like the UI relies on the outdated feature detection logic alone, though.

Again, please rely only on the documentation you find linked here: https://developer.chrome.com/docs/ai/built-in-apis?hl=en#api_status. Feel free of course to feed it into your LLM of choice, but please don't blindly trust anything that spits out window.ai in October 2025. 

Thomas Steiner, PhD—Developer Relations Engineer (blog.tomayac.com, toot.cafe/@tomayac)

Google Spain, S.L.U.

Torre Picasso, Pl. Pablo Ruiz Picasso, 1, Tetuán, 28020 Madrid, Spain

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[sophie]

Thank you. I see the documentation mentions support for multiple languages, but the code only includes examples in English, Japanese, and Spanish. Could you please tell me which languages ​​are specifically supported?

[Thomas Steiner]

Hi Sophie,

You can dynamically find out:

await Summarizer.availability({
  type: "key-points",
  expectedInputLanguages: ["en", "ja", "es"],
  outputLanguage: "es",
  expectedContextLanguages: ["en"],
  sharedContext: "These are requests to summarize articles from a multilanguage newspaper. The users expect a response in Spanish."
});

// "available"

Cheers,

Tom

To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/chrome-ai-dev-preview-discuss/9703deba-dee4-4959-8f98-f463e288e5b9n%40chromium.org.

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Thomas Steiner, PhD—Developer Relations Engineer (blog.tomayac.com, toot.cafe/@tomayac)

Google Spain, S.L.U.

Torre Picasso, Pl. Pablo Ruiz Picasso, 1, Tetuán, 28020 Madrid, Spain

CIF: B63272603

Inscrita en el Registro Mercantil de Madrid, sección 8, Hoja M­-435397 Tomo 24227 Folio 25

----- BEGIN PGP SIGNATURE -----

Version: GnuPG v2.4.8 (GNU/Linux)

iFy0uwAntT0bE3xtRa5AfeCheCkthAtTh3reSabiGbl0ck

0fjumBl3DCharaCTersAttH3b0ttom.xKcd.cOm/1181.

[sophie]

Hi Thomas,

This is precisely what's confusing me. This part of the code seems to only support three languages, but when I tested it in Playground, it supported other languages as well. So I want to know exactly which languages are supported, as this would help me clarify which languages my product supports.

Best,

Sophie

[Thomas Steiner]

Hi Sophie,

Currently querying the `availability()` of your desired languages combination is the only way, but I have opened an Issue asking for a way to make this more ergonomic: https://github.com/webmachinelearning/prompt-api/issues/158. The Summarizer internally depends on the Prompt API, which right now supports English, Spanish, and Japanese.

Cheers,

Tom

Thomas Steiner, PhD—Developer Relations Engineer (blog.tomayac.com, toot.cafe/@tomayac)

Google Spain, S.L.U.

Torre Picasso, Pl. Pablo Ruiz Picasso, 1, Tetuán, 28020 Madrid, Spain

CIF: B63272603

Inscrita en el Registro Mercantil de Madrid, sección 8, Hoja M­-435397 Tomo 24227 Folio 25

----- BEGIN PGP SIGNATURE -----

Version: GnuPG v2.4.8 (GNU/Linux)

iFy0uwAntT0bE3xtRa5AfeCheCkthAtTh3reSabiGbl0ck

0fjumBl3DCharaCTersAttH3b0ttom.xKcd.cOm/1181.

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[sophie]

Thank you. After removing all instances of window.ai, and self.ai, the problem is solved and the feature is working correctly now.

For your team's context: initially, I had Claude directly scrape content from the internet and generate code according to my requirements. This step included `window.ai`. Then I downloaded the entire document (https://developer.chrome.com/docs/ai/summarizer-api#batch_summarization) and had Claude correct it based on the document content. At this point, `self.ai` appeared. We then read the document and checked the code ourselves, but because of the following code snippet, we couldn't make a clear judgment, so we tacitly allowed AI to use `self.ai`.