A2A protocol returns no citations in developer telemetry (message/send + message/stream) — CLI/BizChat do; contradicts m365-semantics citations.md

Summary

The A2A protocol does not return citations in its developer telemetry. For the same agent + prompt where the workiq CLI surfaces citations, an A2A client gets no citation data: no inline [n] markers, no references[], and an empty Answer artifact citation map. This appears to contradict the documented A2A m365 semantics: https://microsoftgraph.visualstudio.com/Graph%20Developer%20Experiences/_git/work-iq-docs?path=/A2A/m365-semantics/citations.md.

Scope — A2A protocol (endpoint https://workiq.svc.cloud.microsoft/a2a/)

Tested both A2A methods with params.configuration.acceptedOutputModes = ["text/plain","application/vnd.ms-workiq.developer-info","application/vnd.ms-workiq-internal.retrieval"], header X-variants: feature.EnableA2AServer:

• message/send -> no references, no inline [n], no targetLink.
• message/stream -> artifacts [Answer, Developer Info, Retrieval Info]; Retrieval has 2 execs/~4 hits; Answer citation map = 0 entries; no inline [n]; hits have no webUrl.

Control — workiq CLI (same agent, same prompt) DOES return citations

workiq ask -q "When is my next holiday?" --agent-id <id> --developer --json returns a top-level references array ({ id, targetLink, isCitedInResponse:true }) and inline [1](https://…Holidays_Canada.docx) in the answer. BizChat renders the same source chips. So the citation data exists end-to-end — the A2A protocol surface is the only place it's missing.

Expected

A2A developer telemetry should expose citations per the m365-semantics citations.md — e.g. a references/citation map (with targetLink + isCitedInResponse) on message/send and on the message/stream Answer artifact — at parity with the CLI/BizChat.

Impact

A2A consumers (dev UIs, eval tools) can't measure citation/grounding. The M365 Copilot evals Citations evaluator scores 0 over A2A. Companion: microsoft/m365-copilot-eval#31.

Start by comparing the A2A message/send and message/stream responses from the documented endpoint with the workiq ask --developer --json control output and m365-semantics/citations.md. Trace how references and the Answer artifact citation map are assembled; done means both A2A methods expose citation data with targetLink and isCitedInResponse, including inline markers where applicable.