- New website/docs/user-guide/messaging/a2a.md: when/where to use A2A
(cross-machine, specialist peers, being callable) vs delegation/kanban
for same-machine multi-agent; enable, outbound tools, inbound surface,
security model, env reference, quick test, troubleshooting. Registered
in sidebars.ts and the messaging index.
- README/DESIGN/plugin.yaml/protocol.py prose updated to name the A2A
v1.0 canonical discovery path /.well-known/agent-card.json (the code
already served both; only the docs lagged).
Two bugs reported by gfdsa (PR #41711 comment, Jul 12) that break the
official a2a-sdk 1.1.0 Python client:
1. Task objects serialized non-spec createdAt/lastModified fields.
The A2A v1.0 Task proto (lf.a2a.v1.Task) only has id, contextId,
status, artifacts, history, metadata. Strict ProtoJSON parsers
reject unknown fields with ParseError. Removed both fields from
build_task(); created_at param kept for call-site compatibility.
2. SSE streaming frames were not JSON-RPC wrapped. A2A v1.0 §9.4
requires data: {"jsonrpc":"2.0","id":...,"result":{StreamResponse}}.
sse_data() now accepts req_id and wraps in JSON-RPC envelope.
sse_done() changed from 'data: {}' to SSE comment ': done' so
SDK doesn't try to parse an empty JSON-RPC response.
All call sites in adapter.py (_emit_terminal, _rpc_message_stream,
_rpc_tasks_subscribe) updated to thread req_id through.
Tests updated: 153 pass (151 unit + 17 integration, including 2 new
tests for JSON-RPC envelope wrapping and fallback behavior).
Refs: gfdsa/a2a-hermes reproduction repo
## File/data Parts (v1.0 unified Part)
- file_part(url=, raw=, filename=, media_type=) builds v1.0 file Parts
- data_part(data, media_type=) builds v1.0 data Parts
- message_with_parts(role, parts, context_id=) builds Messages with mixed Part types
- extract_text now renders file/data Parts into the text stream:
- File with URL: '[file: name] https://url (mediaType)'
- File with raw: '[file: name] N bytes base64-encoded (mediaType)'
- Data: '[data (mediaType)]\n{json}'
- v0.3 file (file.fileWithUri) and data (kind=data) still accepted
- Outbound replies stay text-only (agent produces text)
## Push notification config full CRUD
- get_push_config(task_id, config_id) — retrieve by task, optionally by configId
- list_push_configs(task_id) — list all configs for a task (max 1 per task)
- delete_push_config(task_id, config_id) — remove a config
- New JSON-RPC methods: tasks/pushNotificationConfig/get, /list, /delete
- New adapter handlers: _rpc_push_config_get, _list, _delete
- All return spec-shaped PushNotificationConfig with configId + createdAt
## Tests
- 6 new unit tests for Part builders + extract_text with file/data
- 13 new unit tests for push config get/list/delete (happy + error paths)
- 2 new integration tests over real HTTP:
- test_mixed_parts_delivered_to_agent: file URL + data JSON reach agent
- test_push_config_crud_over_http: full create→get→list→delete cycle
- Old test_extract_text_skips_non_text_parts replaced (now renders, not skips)
Total: 151 tests (134 unit + 17 integration), 0 failed.
DESIGN.md updated: file/data Parts and push config CRUD removed from
out-of-scope list.
Single platform-adapter plugin under plugins/platforms/a2a/ — zero core
edits — that supersedes the entire A2A PR/issue cluster. Built on the
ctx.register_platform + ctx.register_tool surface the codebase now exposes.
Outbound (a2a toolset): a2a_discover / a2a_call / a2a_list let the agent
call any A2A-compliant peer over JSON-RPC message/send. Inbound (platform
adapter): a stdlib http.server serves an Agent Card at
/.well-known/agent.json and routes incoming tasks into the agent's LIVE
gateway session (the #11025 insight) — same agent, full memory — returning
the reply over A2A.
Security on by default: no bearer token => 127.0.0.1-only bind; constant-
time bearer auth; inbound prompt-injection filtering + untrusted-peer
framing; outbound credential redaction; append-only audit log; per-context
conversation persistence outside the compaction pipeline.
Stdlib only (no a2a-sdk). 37 tests incl. a live HTTP round-trip
(card + message/send + reply) and a bearer-auth 401 path.
Teknium
Ben Kamholtz
Kevin (OpenClaw Bot)