Complete the boundary-mirror removal begun with the step mirrors: drop `agent/turn-start` and `agent/turn-end` from the agent event taxonomy. Turn and step boundaries are now read exclusively off the durable `session/event` feed (`turn/start`/`turn/end`/`step/start`/`step/end`) — there is no `agent/*` mirror for any boundary. - loop.ts: delete both turn emits; `closeTurn` loses its `emit` parameter and its now-unreachable idempotency guard (it is called exactly once per turn, on mutually exclusive normal/catch paths); `failTurn` loses the dead post-close branch that only a throwing turn-end LISTENER could reach. - ui-stdio: render turn boundaries from `session/event`, recovering the short agent label from an `agent/created`→id map (the `turn/start` event carries only the turn number, and the session id is not reliably the agent id). ui-stdio is a disposable test REPL, so this migration retires the sole justification the event-domain-semantics RFC gave for KEEPING the turn mirrors. - Tests: reason/turn-number collectors and the boundary-ordering test now read `session/event`; the throwing-turn-boundary-LISTENER tests are deleted (that code path no longer exists). A new test covers the outer-catch disposed branch via a pre-step listener that disposes-then-throws (the surviving real path). - Docs: promote the "remove agent boundary mirror events" RFC to implemented (amended/narrowed — `agent/steering` is RETAINED, not a boundary mirror); update the event-domain-semantics + turn-enclosure RFCs, architecture.md, the cookbook, the ACP/agent/ui-stdio prose, and regenerate the cordis catalog. `agent/steering` and `agent/stream-chunk` are explicitly out of scope (not durable-boundary mirrors). ACP is unaffected — it already settles from the log's `turn/end` + `agent/status`; snapshot goldens are byte-unchanged.
ui/ — editor/client integration surfaces
Integrations that expose the agent to an external editor or client. These are product packages: a real surface a user drives the harness through.
| Package | Role | ctx key |
|---|---|---|
acp/ |
Agent Client Protocol bridge: serves the agent to an ACP editor (Zed) over JSON-RPC stdio | (drives ctx.agents/ctx.sessions) |
stdio-agent/ |
Terminal stdio chat APP: the agent-core spine + console logger + readline UI + a pre-created main agent, with a bin |
(composition + bin) |
acp-agent/ |
ACP server APP: the agent-core spine + JSONL persistence + the acp bridge (no stdout logger), with a bin |
(composition + bin) |
A UI integration is a client-driver plugin, not a loop change and not a capability seam: it consumes the existing agent/* event taxonomy and the dsh-agent factory. The readline ui-stdio plugin is the unstructured analogue but lives in support/ because it exists chiefly for the examples and the coverage gate — ui/ is reserved for surfaces shipped as product.
stdio-agent and acp-agent are the two app packages: each composes the core/agent-core spine with its coupled front-door cluster (and owns the boot bin), so a leaf cordis.yml is the swappable backends plus one app entry plus any optional product tools. They live in ui/ because each IS a user-facing front door; the stdout-purity coupling (logger vs. no logger) becomes a property of the artifact rather than a leaf convention.