Adds Agentic Audience by therevoltingx · Pull Request #210 · InteractiveAdvertisingBureau/openrtb

therevoltingx · 2026-03-22T00:26:48Z

Add Agentic Audiences Community Extension

This PR adds a community extension document for Agentic Audiences in OpenRTB. Agentic Audiences (formerly the User Context Protocol/UCP) is an IAB Tech Lab standard that defines how intelligent agents in advertising exchange vector embeddings representing consumer intent and ad response.

Summary

The extension specifies how embeddings are sent in bid requests. They are placed in BidRequest.user.data using the standard Data and Segment objects.

Structure

Each provider uses one Data object with a name (provider identifier) and a segment array.
Each segment is a standard OpenRTB Segment with id, name, and ext.
Agentic Audiences fields go in Segment.ext: ver, vector, model, dimension, and type.
The type array indicates signal type: 1 = identity, 2 = contextual, 3 = reinforcement.

Files Changed

Added: extensions/community_extensions/agentic-audiences.md – full specification with attribute definitions, embedding type values, single and multiple provider examples, client-side storage notes, and implementation guidance
Modified: extensions/community_extensions/README.md – added Agentic Audiences entry

References

patmmccann · 2026-03-22T00:56:19Z

extensions/community_extensions/agentic-audiences.md

+
+## Request Change
+
+This community extension defines how Agentic Audiences embeddings are conveyed in OpenRTB bid requests. The extension uses the existing `Data` and `Segment` objects in `BidRequest.user.data`. Each data provider supplies one or more segment entries, where each entry is a vector embedding with metadata describing its type and model.


Community extensions use ext fields, so all these extra fields should hand off user.data.sement.ext if you're going to use segment

patmmccann · 2026-03-22T00:56:43Z

extensions/community_extensions/agentic-audiences.md

+# Agentic Audiences in OpenRTB
+
+**Sponsors**: LiveRamp
+


You can add raptive

patmmccann · 2026-03-22T00:57:39Z

extensions/community_extensions/agentic-audiences.md

+    "data": [
+      {
+        "name": "live_ramp",
+        "segment": [


The next five fields should hang off ext not segment directly or this isn't an extension.

Also according to the aa spec this is rather incomplete

i fixed it so that the aa specific fields are under ext. in regards to the incompleteness.
these were the minimum ones we thought would be needed in openrtb.
do you believe we should add all fields in the aa spec? are you concerned with request size bloat?

I am worried about that but the appendix audience spec says a bunch of fields are required and then it lists even more optional fields, so I'm not sure which is right

Fixed the ext, ty

The aa spec's required fields could be pruned down a bit. Also the original spec was meant to cover the targeting side as well, for example metric specification isn't as relevant on the supply side.

we can:

we move forward with this small set of fields and add more as needed

we make it follow the AA spec exactly, including nested fields and long form names

@adam-zimmerman @patmmccann i think we should move forward with #1 and add fields as needed by the community

Agree, let's stick with #1.

Okay but then you should change the aa spec to move more things to optional

patmmccann · 2026-03-22T00:58:42Z

extensions/community_extensions/agentic-audiences.md

+  "user": {
+    "data": [
+      {
+        "name": "live_ramp",


Liveramp is one word

patmmccann · 2026-03-22T01:01:42Z

extensions/community_extensions/agentic-audiences.md

+        "name": "live_ramp",
+        "segment": [
+          {
+            "ver": "1.0",


The spec calls for much longer vectors and the arrays of floats would require much more precision than one decimal place. I think this example is misleading. It is likely wise to use a better data structure than this vector spelled out so poorly compacted

moved to ext but this is for version. so version of the model that was used to generate the embedding. not the actual vector or array of floats.

Yeah I meant the line below, looks like we already came to agreement ty

patmmccann · 2026-03-22T01:15:18Z

extensions/community_extensions/agentic-audiences.md

+        "segment": [
+          {
+            "ver": "1.0",
+            "vector": [0.1, -0.2, 0.3],


Maybe something like this instead?

const floats = [ 1.2345678, -2.5, 0.0, 3.1415927, 12345.678, -0.00012345, 42.42, -999.999, 0.000001, 987654.25 ]; function floats32ToBase64(arr) { const buffer = new ArrayBuffer(arr.length * 4); const view = new DataView(buffer); arr.forEach((x, i) => view.setFloat32(i * 4, x, true)); // little-endian const bytes = new Uint8Array(buffer); let binary = ""; for (const b of bytes) binary += String.fromCharCode(b); return btoa(binary); } console.log(floats32ToBase64(floats)); // UQaePwAAIMAAAAAA2w9JQLbmQEZbcgG5FK4pQvD/ecS9N4Y1ZCBxSQ==

you're proposing that instead of an array of floats, that the array is encoded to base64. is that to reduce size of the request or is there an issue with just transporting an array of floats?

Just to reduce the size, the spec talks about it being 512 or 1024 entries long

I was also thinking the array itself should be base64 encoded

@patmmccann @adam-zimmerman i went ahead and changed vector to be a base64 encoded value. along with examples on encoding and decoding

therevoltingx · 2026-03-27T16:06:56Z

@patmmccann @adam-zimmerman I have addressed all your comments. Can you please review and approve the entire PR so we can move forward thanks.

therevoltingx · 2026-03-30T02:47:00Z

@hillslatt we're good to merge this PR

Miguel Morales added 2 commits March 21, 2026 17:24

adds agentic audiences

8340438

updates agentic doc

b6e942b

therevoltingx mentioned this pull request Mar 22, 2026

Adds Tech Lab Agentic Audiences prebid/Prebid.js#14626

Open

patmmccann reviewed Mar 22, 2026

View reviewed changes

Miguel Morales added 3 commits March 21, 2026 18:38

cleans up agentic docs

fb97aac

cleans up agentic docs

d85e701

updates vector to use base64

ba5813f

Miguel Morales added 2 commits March 27, 2026 09:16

readds dimension

237f27d

adds not about dsp validation

01d6a81

patmmccann approved these changes Mar 28, 2026

View reviewed changes

hillslatt merged commit eebe6bd into main Mar 30, 2026


		## Request Change

		This community extension defines how Agentic Audiences embeddings are conveyed in OpenRTB bid requests. The extension uses the existing `Data` and `Segment` objects in `BidRequest.user.data`. Each data provider supplies one or more segment entries, where each entry is a vector embedding with metadata describing its type and model.

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therevoltingx commented Mar 22, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Add Agentic Audiences Community Extension

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therevoltingx commented Mar 27, 2026

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therevoltingx commented Mar 30, 2026

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therevoltingx commented Mar 22, 2026 •

edited

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