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fix(spec): Added clarifying text around messages and artifacts#1424

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darrmi/message-clarity
Jan 29, 2026
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fix(spec): Added clarifying text around messages and artifacts#1424
darrelmiller merged 6 commits intomainfrom
darrmi/message-clarity

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This pull request updates the A2A protocol specification to clarify the distinction between Messages and Artifacts, and makes a minor adjustment to protocol negotiation requirements.

@darrelmiller darrelmiller requested a review from a team as a code owner January 29, 2026 17:53
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Summary of Changes

Hello @darrelmiller, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the A2A protocol specification by providing crucial clarity on the fundamental distinction between Messages and Artifacts, ensuring a more precise understanding of their respective uses. Additionally, it refines the protocol negotiation guidelines by removing a previous restriction.

Highlights

  • Clarification of Messages and Artifacts: A new section (3.7) has been added to the A2A protocol specification to clearly define the distinct roles of 'Messages' and 'Artifacts'. Messages are primarily for communication (task initiation, clarification, status, interaction), while Artifacts are designated for delivering task outputs. This section also clarifies the persistence and reliability expectations for Messages.
  • Protocol Negotiation Requirement Adjustment: The specification has been updated to remove the explicit requirement stating 'No Dynamic Negotiation' for A2A protocols, subtly adjusting the guidelines around protocol negotiation.
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Code Review

This pull request provides a valuable clarification on the roles of Messages and Artifacts within the A2A protocol specification, clearly defining their distinct purposes. It also removes the constraint against dynamic protocol negotiation, which offers more flexibility. The changes are well-written, but I've noted a couple of minor typos in the new documentation section.

@darrelmiller darrelmiller added this to the 1.0 milestone Jan 29, 2026
darrelmiller and others added 2 commits January 29, 2026 13:20
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Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
@darrelmiller darrelmiller removed this from the 1.0 milestone Jan 29, 2026
@amye amye added this to the 1.0 milestone Jan 29, 2026
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/vote

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git-vote bot commented Jan 29, 2026

Vote created

@darrelmiller has called for a vote on fix(spec): Added clarifying text around messages and artifacts (#1424).

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@a2aproject/a2a-tsc

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LGTM

@darrelmiller darrelmiller merged commit b03d141 into main Jan 29, 2026
12 of 13 checks passed
@darrelmiller darrelmiller deleted the darrmi/message-clarity branch January 29, 2026 19:44
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git-vote bot commented Jan 30, 2026

Vote closed

The vote passed! 🎉

62.50% of the users with binding vote were in favor and 0.00% were against (passing threshold: 51%).

Summary

In favor Against Abstain Not voted
5 0 0 3

Binding votes (5)

User Vote Timestamp
@SivaNSAP In favor 2026-01-29 19:40:49.0 +00:00:00
@ToddSegal In favor 2026-01-29 19:41:00.0 +00:00:00
@darrelmiller In favor 2026-01-29 19:40:28.0 +00:00:00
@muscariello In favor 2026-01-29 19:41:09.0 +00:00:00
@spetschulatSFDC In favor 2026-01-29 19:40:34.0 +00:00:00

darrelmiller pushed a commit that referenced this pull request Mar 12, 2026
🤖 I have created a release *beep* *boop*
---


## [1.0.0](v0.3.0...v1.0.0)
(2026-03-12)


### ⚠ BREAKING CHANGES

* **spec:** Combine `TaskPushNotificationConfig` and
`PushNotificationConfig`
([#1500](#1500))
* **spec:** remove duplicated ID from the create task push config
request ([#1487](#1487))
* **spec:** pluralize configs in `ListTaskPushNotificationConfigs`
([#1486](#1486))
* **spec:** Add LF prefix to the package.
([#1474](#1474))
* **spec:** Switch to non-complex IDs in requests
([#1389](#1389))
* **spec:** Standardize spelling of "canceled" to use American Spelling
throughout ([#1283](#1283))
* **spec:** Align enum format with ADR-001 ProtoJSON specification
([#1384](#1384))
* **spec:** Remove redundant `final` field from `TaskStatusUpdateEvent`
([#1308](#1308))
* **spec:** Move `extendedAgentCard` field to `AgentCapabilities`
([#1307](#1307))
* **spec:** Fixes for the last_updated_after field
([#1358](#1358))
* **spec:** modernize oauth 2.0 flows - remove implicit/password, add
device code / pkce
([#1303](#1303))
* **spec:** Make "message" field name consistent between protocol
bindings ([#1302](#1302))
* **spec:** Remove deprecated fields from a2a.proto for v1.0 release
([#1301](#1301))
* **spec:** Rename `supportsAuthenticatedExtendedCard` to
`supportsExtendedAgentCard`
([#1222](#1222))
* **spec:** Remove v1s from a2a url http bindings
* **spec:** Large refactor of specification to separate application
protocol definition from mapping to transports

### Features

* **spec:** Add `tasks/list` method with filtering and pagination to the
specification
([0a9f629](0a9f629))
* **spec:** modernize oauth 2.0 flows - remove implicit/password, add
device code / pkce
([#1303](#1303))
([525ff38](525ff38))
* **spec:** Natively Support Multi-tenancy on gRPC through an additional
scope field on the request.
([#1195](#1195))
([cfbce32](cfbce32)),
closes [#1148](#1148)
* **spec:** Provide ability for SDKs to be backwards compatible.
([#1401](#1401))
([227e249](227e249))
* **spec:** Remove v1s from a2a url http bindings
([1bd263f](1bd263f))


### Bug Fixes

* Add missing metadata field to Part message in gRPC specification
([#1019](#1019))
([b3b266d](b3b266d)),
closes [#1005](#1005)
* Add name field to FilePart protobuf message
([#983](#983))
([2b7cb6f](2b7cb6f)),
closes [#984](#984)
* Clarify blocking calls return on interrupted states
([#1403](#1403))
([0655ff3](0655ff3))
* **doc:** Makes JSON-RPC SendMessage response clearer
([#1241](#1241))
([5792804](5792804))
* **docs:** Clearer wording around context id.
([#1588](#1588))
([dec790a](dec790a))
* **grpc:** Fix inconsistent property name between gRPC and JSON-RPC in
Message object ([#1100](#1100))
([2a1f819](2a1f819))
* **grpc:** missing field in gRPC spec - state_transition_history
([#1138](#1138))
([a2de798](a2de798)),
closes [#1139](#1139)
* **grpc:** Update `CreateTaskPushNotificationConfig` endpoint to
`/v1/{parent=tasks/*/pushNotificationConfigs}`
([#979](#979))
([911f9b0](911f9b0))
* **proto:** Add icon_url to a2a.proto
([#986](#986))
([17e7f62](17e7f62))
* **proto:** Adds metadata field to A2A DataPart proto
([#1004](#1004))
([a8b45dc](a8b45dc))
* Remove unimplemented state_transition_history capability field
([#1396](#1396))
([c768a44](c768a44)),
closes [#1228](#1228)
* Restore CreateTaskPushNotificationConfig method naming
([#1402](#1402))
([d14f410](d14f410))
* Revert "chore(gRPC): Update a2a.proto to include metadata on
GetTaskRequest" ([#1000](#1000))
([e6b8c65](e6b8c65))
* Simplify Part message structure by flattening FilePart and DataPart
([#1411](#1411))
([bfae8f7](bfae8f7))
* **spec:** Add LF prefix to the package.
([#1474](#1474))
([a54e809](a54e809))
* **spec:** add metadata to `CancelTaskRequest`
([#1485](#1485))
([c441b91](c441b91)),
closes [#1484](#1484)
* **spec:** Added clarification on timestamps in HTTP query params
([#1425](#1425))
([6292104](6292104))
* **spec:** Added clarifying text around messages and artifacts
([#1424](#1424))
([b03d141](b03d141))
* **spec:** Adjust field number for `ListTasksRequest.tenant` to prevent
missing number ([#1470](#1470))
([cd16c52](cd16c52))
* **spec:** Clarify contextId behavior when message is sent with taskId
but without contextId
([#1309](#1309))
([a336a5a](a336a5a))
* **spec:** Clarify versioning strategy and client responsibilities in
protocol specification
([#1259](#1259))
([a4afeea](a4afeea))
* **spec:** Fix/1251 clarify authentication scheme
([#1256](#1256))
([3e6c7db](3e6c7db))
* **spec:** Fixes for the last_updated_after field
([#1358](#1358))
([0e204bf](0e204bf))
* **spec:** Make "message" field name consistent between protocol
bindings ([#1302](#1302))
([1e5f462](1e5f462)),
closes [#1230](#1230)
* **spec:** make `history_length` optional
([#1071](#1071))
([0572953](0572953))
* **spec:** pluralize configs in `ListTaskPushNotificationConfigs`
([#1486](#1486))
([cf735cb](cf735cb))
* **spec:** Remove config from binding.
([#1587](#1587))
([010b9cc](010b9cc))
* **spec:** Remove deprecated fields from a2a.proto for v1.0 release
([#1301](#1301))
([60f83c3](60f83c3)),
closes [#1227](#1227)
* **spec:** remove duplicated ID from the create task push config
request ([#1487](#1487))
([393898d](393898d))
* **spec:** Remove metadata field from ListTasksRequest
([#1235](#1235))
([b6ef9ee](b6ef9ee))
* **spec:** Remove reserved and fix tags ordering
([#1494](#1494))
([1997c9d](1997c9d))
* **spec:** Rename `supportsAuthenticatedExtendedCard` to
`supportsExtendedAgentCard`
([#1222](#1222))
([c196824](c196824)),
closes [#1215](#1215)
* **spec:** Standardize spelling of "canceled" to use American Spelling
throughout ([#1283](#1283))
([4dd980f](4dd980f))
* **spec:** Suggest Unique Identifier fields to be UUID
([#966](#966))
([00cf76e](00cf76e))
* **spec:** Switch to non-complex IDs in requests
([#1389](#1389))
([2596c1c](2596c1c)),
closes [#1390](#1390)
* **spec:** Update security schemes example
([#1364](#1364))
([f9a8f5b](f9a8f5b))
* Update the Java tutorials and descriptions
([#1181](#1181))
([202aa06](202aa06))


### Documentation

* **spec:** Align enum format with ADR-001 ProtoJSON specification
([#1384](#1384))
([810eaa1](810eaa1)),
closes [#1344](#1344)


### Code Refactoring

* **spec:** Combine `TaskPushNotificationConfig` and
`PushNotificationConfig`
([#1500](#1500))
([d1ed0da](d1ed0da))
* **spec:** Large refactor of specification to separate application
protocol definition from mapping to transports
([b078419](b078419))
* **spec:** Move `extendedAgentCard` field to `AgentCapabilities`
([#1307](#1307))
([40d6286](40d6286))
* **spec:** Remove redundant `final` field from `TaskStatusUpdateEvent`
([#1308](#1308))
([5b101cc](5b101cc))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: Amye Scavarda Perrin <amye@amye.org>
Co-authored-by: Holt Skinner <13262395+holtskinner@users.noreply.github.com>
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[Bug]: Clarify agent responsibilities for including state messages in Task message history

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