[agno A2A] interface only accepts v0.3 wire format — rejects A2A v1.0 clients (SendMessage/ROLE_USER → HTTP 4xx)

## Observed symptom [Bug] A2A interface only accepts v0.3 wire format — rejects A2A v1.0 clients (SendMessage / ROLE_USER → HTTP 400) ## Description Agno's A2A interface (`agno.os.interfaces.a2a`) only speaks the **A2A Protocol v0.3** wire format and rejects **A2A Protocol v1.0** clients with `HTTP 400`. This blocks any v1.0-compliant client (e.g. the [`@bacnh85/pi-a2a`](https://github.com/bacnh85/pi-a2a) extension for the Pi coding agent, or any client built on `a2a-sdk>=1.0`) from sending a task to an agno-exposed Agent/Team/Workflow. Two concrete symptoms, both coming from the same root cause: 1. **Wire format:** a v1.0 `message/send` request is rejected because agno validates against `a2a.types.SendMessageRequest` (v0.3), which requires `method == "message/send"` and `role in {"user","agent"}`. A v1.0 client sends `method == "SendMessage"` and `role == "ROLE_USER"`, so validation fails. 2. **Agent Card `url`:** th ## Literal error text ``` A2A v1.0 rejected ``` ## Environment GitHub issue agno-agi/agno #10387; state=open ## Trigger / context ## Description Agno's A2A interface (`agno.os.interfaces.a2a`) only speaks the **A2A Protocol v0.3** wire format and rejects **A2A Protocol v1.0** clients with `HTTP 400`. This blocks any v1.0-compliant client (e.g. the [`@bacnh85/pi-a2a`](https://github.com/bacnh85/pi-a2a) extension for the Pi coding agent, or any client built on `a2a-sdk>=1.0`) from sending a task to an agno-exposed Agent/Team/Workflow. Two concrete symptoms, both coming from the same root cause: 1. **Wire format:** a v1.0 `message/send` request is rejected because agno validates against `a2a.types.SendMessageRequest` (v0.3), which requires `method == "message/send"` and `role in {"user","agent"}`. A v1.0 client sends `method == "SendMessage"` and `role == "ROLE_USER"`, so validation fails. 2. **Agent Card `url`:** the card advertises the **streaming** endpoint (`…/v1/message:stream`) as `url`, so a generic v1.0 client that dispatches to `card.url` lands on the streaming route with a non-stream method and fails. ## Steps to Reproduce Run an agno app with the A2A interface exposed (any Agent/Team/Workflow), then send an **A2A v1.0** `SendMessage` request to its `message:send` endpoint: ```bash # card reports protocolVersion 0.3.0 curl -s http://<host>/a2a/teams/<id>/.well-known/agent-card.json | jq '{protocolVersion, url}' # v1.0 client wire (what a2a-sdk 1.x / pi-a2a send) → 400 curl -s -X POST http://<host>/a2a/teams/<id>/v1/message:send \ -H 'Content-Type: application/json' \ -d '{ "jsonrpc ## Source evidence - https://github.com/agno-agi/agno/issues/10387 (2026-09-21T12:57:13Z) — GitHub issue #10387 ## Freshness - classification: FRESH_14D - retrieved_at: 2026-10-02T09:43:03.388295Z - scout_id: C3a94f70304 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome.