Pre-release Harn is pre-1.0 — the language, standard library, and CLI may change between releases. See the release notes

Protocol filing status ledger

Last verified: 2026-07-03 UTC.

This ledger records direct upstream reads for the protocol-contribution threads that back the RFCs in this directory. It is intentionally factual: only record a state here after fetching the upstream discussion, PR, or issue directly.

In Diataxis terms, this is reference material. It lists current facts and links; it is not a how-to guide or a design explanation.

Public follow-up posture

Upstream comments and PRs should use neutral ecosystem evidence, peer behavior, and public prior art. Do not lead with Harn or Burin-specific adoption claims. A local implementation can inform our internal confidence, but public posts should stand on protocol semantics and independently checkable examples.

ACP

Context as of 2026-07-03: the v2 RFD collection was marked "Active" on 2026-07-02 and is the most active area of the repo, but every v2 RFD PR merged since 2026-06-01 was maintainer-authored. Externally-authored RFD PRs (including #1261) sit in review while their content gets absorbed into unstable-v2 commits. Plan for discussions to be the unit of influence, not PR merges. Two v2 docs matter for our filings: the merged session-resume-replay RFD (unified session/load + session/resume, optional replayFrom cursor) is the substrate any session/suspend follow-up must sit on, and open PR #1237 (client-provided system prompt) overlaps the session/remind territory and should be differentiated against, not ignored.

ItemVerified stateNotes
agentclientprotocol/agent-client-protocol#1220Open discussion.A maintainer invited an RFD. The follow-up RFD is PR #1261.
agentclientprotocol/agent-client-protocol#1261Open PR, mergeable, review still required as of 2026-07-03; no maintainer review since the 2026-06-27 rebase.Rebase note posted at discussioncomment-4819339360.
agentclientprotocol/agent-client-protocol#484Closed in favor of #1261.Relevant predecessor for prompt queueing / steer-via-yield framing.
agentclientprotocol/agent-client-protocol#1224Open discussion, no maintainer response visible as of 2026-07-03.Ambient system-role context injection / reminder sibling of #1220; the 2026-06-27 next-step ping (discussioncomment-17455653) is still unanswered.
agentclientprotocol/agent-client-protocol#1233Open discussion, no maintainer response visible as of 2026-07-03.session/suspend + session/await_resumption. A substantive v2 alignment comment was posted 2026-07-03 (discussioncomment-17525582): resume-side enrichment dropped in favor of the merged session-resume-replay RFD, offering an RFD PR if maintainers want one.
agentclientprotocol/registry#397Open PR, no review decision as of 2026-07-03.Registry submission; entry refreshed to Harn v0.8.158 with revalidated archive URLs on 2026-06-30.

A2A

Context as of 2026-07-03: A2A v1.0.0 shipped 2026-03-12 (v1.0.1 on 2026-05-28), which predates our 2026-05-17 filings. v1.0 renamed operations to PascalCase across all bindings (message/sendSendMessage, subscription → SubscribeToTask), moved enums to SCREAMING_SNAKE_CASE per ProtoJSON, removed kind discriminators, and made a2a.proto the normative source of truth. Both filed discussions and the RFCs in this directory originally used pre-1.0 naming; the RFCs were revised to v1.0 conventions on 2026-07-03, and any follow-up upstream post should use v1.0 names.

ItemVerified stateNotes
a2aproject/A2A#1857Open discussion.Separate idempotency / post-cancel semantics thread; not a pause/reminder substitute.
a2aproject/A2A#1858Open discussion, no maintainer/TSC reply visible as of 2026-07-03.Good-faith community feedback converged toward one PAUSED state plus a structured pause object; the draft-PR-vs-extension next-step ping (discussioncomment-17455657) is still unanswered.
a2aproject/A2A#1937Open issue, last updated 2026-06-19.Context-binding profile for delegated authority — binds an already-valid delegation to a task/session/target/scope. Complement of (not substitute for) the actor-chain extension RFC; best anchor thread for that filing.
a2aproject/A2A#153Open issue (since 2025-06).Confused-deputy framing for A2A; canonical motivation citation for payload-visible principals.
a2aproject/A2A#2027Filed 2026-07-03 (Ideas category).InjectTaskReminder ambient-context discussion, from the reminder RFC with A2A v1.0 naming. Dupe-checked before filing.
a2aproject/A2A#2028Filed 2026-07-03.Actor-chain extension proposal from the actor-chain RFC, anchored to #1937 / #153.

MCP and OAuth Identity

ItemVerified stateNotes
modelcontextprotocol/modelcontextprotocol#2736Open discussion, no maintainer response as of 2026-07-03; first substantive community reply landed 2026-06-27 after the SEP-path ping (discussioncomment-17455659).The reply endorses a deliberately small first SEP: one host-owned limit envelope plus one typed stop/failure shape, with a decision-basis receipt and append-only follow-up records. A narrowed-scope restatement was posted 2026-07-03 (discussioncomment-17525578), offering to draft the SEP unless maintainers object.
modelcontextprotocol/modelcontextprotocol#3007Filed 2026-07-03 (Ideas - General).notifications/reminder server→host ambient-context discussion, from the reminder RFC. Dupe-checked before filing.
modelcontextprotocol/modelcontextprotocol#3008Filed 2026-07-03 (Ideas - General).authenticatedIdentity pre-SEP discussion, from the identity RFC; progressing to a SEP requires an auth-area maintainer sponsor.
modelcontextprotocol/modelcontextprotocol#214Closed.Maintainer guidance on 2026-01-16 pointed custom auth pieces toward modelcontextprotocol/ext-auth.
modelcontextprotocol/ext-auth#13Open, no activity since 2026-01-31.Maintainer response says Enterprise-Managed Authorization does not currently support distinguishing agent vs user identity and points to ID-JAG issue #73.
oauth-wg/oauth-identity-assertion-authz-grant#73Open.The live venue for actor-chain work: workload / agent identity SSO and explicit delegated on-behalf-of access, reusing RFC 8693 act. Implementer feedback posted 2026-07-03 (issuecomment-4878092226) per the positioning note.
oauth-wg/oauth-identity-assertion-authz-grant#80Closed as completed and milestoned 2026-04-22.Optional actor_token proposal split out from #73; folded into the #73 direction rather than rejected.
modelcontextprotocol/modelcontextprotocol#1299Closed as completed 2025-09-02.SEP-1299 is server-side OAuth flow management, unrelated to a server→client identity surface; it does not claim the authenticatedIdentity slot.
modelcontextprotocol/modelcontextprotocol discussion #1827Open discussion, unanswered (opened 2025-11-17).upstream_identity propagation, client→server — the opposite direction from the authenticatedIdentity RFC; the two compose.

Local follow-up candidates

  • Keep ACP PR #1261 conflict-free against upstream main while it waits on maintainer review, and keep the public framing about queue/steer anchored in existing editor/agent behavior rather than local adoption.
  • A2A #1858: the RFC in this directory now matches the converged single-state PAUSED + pause object. A draft PR is ready to cut if maintainers answer the pending draft-PR-vs-extension question.
  • MCP #2736: the narrowed-scope reply is posted; if no objection lands, the next step is drafting the SEP itself (seps/0000-sampling-budget-caps.md PR with a maintainer sponsor).
  • MCP #3008: progressing past discussion requires an auth-area maintainer sponsor; that outreach is the next step if the thread gets traction.
  • All 2026-07-03 filings are new threads awaiting first responses; no re-pings without new substance.