fix: Revert "chore(gRPC): Update a2a.proto to include metadata on GetTaskRequest"#1000
fix: Revert "chore(gRPC): Update a2a.proto to include metadata on GetTaskRequest"#1000
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…equest (…" This reverts commit f0d48cd.
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Summary of Changes
Hello @pwwpche, 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 reverts a previous change that added a "metadata" field of type "google.protobuf.Struct" to the "GetTaskRequest" message in "a2a.proto". This field was incompatible with REST GET requests, as "Struct" cannot be serialized into a query parameter, which caused failures during API discovery document generation. The revert resolves this issue by removing the problematic field.
Highlights
- Revert of Incompatible Field: This pull request reverts a previous change that introduced a "metadata" field (of type "google.protobuf.Struct") into the "GetTaskRequest" message.
- API Compatibility Fix: The "metadata" field was problematic because "google.protobuf.Struct" cannot be serialized as a query parameter for REST GET requests, leading to errors during API discovery document generation.
- Protocol Buffer Definition Update: The "metadata" field has been removed from the "GetTaskRequest" message definition in "specification/grpc/a2a.proto".
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Code Review
This pull request correctly reverts the addition of a metadata field to GetTaskRequest in a2a.proto. As noted in the description, a google.protobuf.Struct cannot be serialized into a query parameter for HTTP GET requests, which was causing issues with API discovery document generation. The revert is a necessary fix. However, this change highlights an inconsistency within the broader A2A specification. The JSON and TypeScript definitions for the equivalent tasks/get operation still include a metadata field. To ensure consistency across all protocol definitions (gRPC, JSON-RPC, and REST), the other specification files should be aligned with this change. I've left a specific comment on the change with more details.
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I think we should remove it from the TaskQueryParams as well. It doesn't make sense there |
ToddSegal
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Approved per TSC discord discussion. This change should not have been merged into main to begin with. So reverting that mistake. That being said, something like this should be supported by defining official serialization mechanism for struct -> queryParam in the spec(s). Need parity between all transports and it is not there for this method.
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I believe that the jsonrpc method should not have the metadata field either. For GetTask it is unclear what value this provides, and as of now, none of the implementations utilize this |
🤖 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>
Reverts #996
Fixes #1002
GetTaskRequest in the REST protocol is a GET. GET does not have request body, and all fields in GET should be serializable to a query param.
metadata when being a struct cannot be serialized to query param, and this is causing failure during API discovery doc generation
http: map field 'google.protobuf.Struct.fields' referred to by message 'a2a.v1.GetTaskRequest' cannot be mapped as an HTTP parameter.