session 2026-08-30 [Claude Code]

Author: acn-ericlaw

memory/continuity.md

@@ -13,11 +13,12 @@
 ## Project State
 
 - **project:** mercury-python (PyPI: `mercury-composable`)
-- **status:** pre-release 0.1.0 (unreleased) — the Python member of the Mercury Composable
+- **status:** v4.12.0 merged to main (the progressive-rendering milestone, engine lock-step
+  version line; PyPI publish still pending) — the Python member of the Mercury Composable
   polyglot initiative: a lightweight Event-over-HTTP function host + thin client, repurposed
   August 2026 (legacy language pack in git history only)
 - **last_enabled:** 2026-08-22
-- **last_session:** 2026-08-26 | agent: Claude Code (2026-08-26-003023)
+- **last_session:** 2026-08-30 | agent: Claude Code (2026-08-30-045556)
 - **last_review:** (none yet)
 - **last_invariant_check:** (none yet)
 - **repo:** ~/sandbox/mercury-python (origin: github.com/Accenture/mercury-python)
@@ -27,8 +28,9 @@
 > Canonical live home for the current stack — language version, dependencies, tool
 > versions. `instructions.md` keeps only a high-level descriptor and points here.
 
-- Python ≥ 3.10; build backend **hatchling**; package `mercury-composable` v0.1.0
-  (unreleased), wheel from `src/mercury_composable`
+- Python ≥ 3.10; build backend **hatchling**; package `mercury-composable` v4.12.0
+  (merged 2026-08-30, engine lock-step version line; PyPI publish pending), wheel from
+  `src/mercury_composable`
   <!-- id: stack-python-hatchling | created: 2026-08-22 | last_used: 2026-08-22 | uses: 1 | tier: working | origin: 2026-08-22-171555 -->
 - Runtime deps: `aiohttp` >=3.10,<4 (Event API host), `msgpack` >=1,<2 (envelope codec),
   `PyYAML` >=6,<7 (config); dev: `pytest` >=8 + `pytest-asyncio` >=0.23 (`asyncio_mode=auto`)
@@ -93,6 +95,18 @@
 
 ## Open Threads
 
+- [x] (feature — **MERGED 2026-08-30 as
+  [PR #21](https://github.com/Accenture/mercury-python/pull/21) true merge `bfca7e4`
+  carrying `d50986a`; tree verified; v4.12.0 milestone, all four repos lock-step)
+  **The progressive-rendering round: event streaming (engines' envelope-mode SSE
+  contract, reply_to bus mechanism, stream/stream_to consumers), business
+  correlation-id continuity, full span lineage with the engines' distributed-trace
+  dataset on stdout, app-log-context with the packaged default template, sender
+  attribution.** Lessons: detach long-lived workers from the creating task's
+  contextvars; install the log-context config before its own warning logs; RPC legs
+  emit no dataset (engine parity). origin: 2026-08-30-045556.
+  <!-- id: ot-streaming-telemetry-round-20260830 | created: 2026-08-30 | last_used: 2026-08-30 | uses: 1 | tier: working | origin: 2026-08-30-045556 -->
+
 - [x] (P4 docs — **SHIPPED and LIVE 2026-08-24**, same day as plan ratification)
   **Documentation site "Composable for Python"** — engine Material theme, 13 files
   incl. the one-page AI agent guide + llms.txt; live at accenture.github.io/mercury-python.
@@ -153,11 +167,11 @@
 > the archive once older than `archive_window` sessions. Don't archive them by hand.
 
 - [ ] **(blueprint) Publish behind the interop gate.** The wrapper is complete and green
-  (tests incl. the shared golden vectors; cross-wrapper interop proven; the
-  composable-example flow executed a Python function unchanged) but **unreleased** — the
-  Vision's "releasable on its own cadence" is unmet until 0.1.0 ships to PyPI with
-  protocol-compat versioning and the interop gate green per release (design P5/D6).
-  Publishing itself is Eric-gated (ownership, cadence, supply-chain posture).
+  and now versioned **v4.12.0 on main** (the milestone merge, 2026-08-30 — the version
+  aligns with the engine lock-step line, superseding the 0.1.0 plan), with the interop
+  gate green (the progressive-rendering interop report). The Vision's "releasable on its
+  own cadence" is unmet until it ships to PyPI; publishing itself stays Eric-gated
+  (ownership, cadence, supply-chain posture; design P5/D6).
   → serves: vision-mercury-python
   <!-- id: bp-publish-interop-gate | created: 2026-08-22 | last_used: 2026-08-22 | uses: 1 | tier: working | origin: 2026-08-22-173136 -->
 

memory/sessions/2026-08-30-045556.md

@@ -0,0 +1,67 @@
+# Session (2026-08-30T04:55:56.000Z)
+
+**Agent:** Claude Code
+
+## Summary
+
+**The progressive-rendering round, shipped as the v4.12.0 milestone.** Merged as
+[PR #21](https://github.com/Accenture/mercury-python/pull/21) true merge `bfca7e4`
+carrying gated `d50986a` (amended once for an IDE type-narrowing finding); tree
+verified == gated; branches deleted both ends. The version jumps 0.1.0 -> **4.12.0**,
+aligning with the engine lock-step line (Eric's call: all four repos ship this
+milestone at the same version).
+
+What shipped (each mirrored the engines' contract exactly; node twin in lock-step):
+
+1. **Event streaming** (engines' Phase-2/3 twin): `EventStreamWriter` producer
+   (interceptor functions), the streaming `/api/event` host speaking the hybrid
+   envelope-mode SSE dialect (pinned 406/503/408 messages, single-shot
+   byte-identical), `PostOffice.stream()` async-iterator consumer with dialect
+   conformance guards, `stream_to()` relay composition - on the primitive bus's
+   new reply_to mechanism (envelope-routed local delivery + per-request reply
+   sinks; Eric's ruling: consistency, not orchestration).
+2. **Business correlation-id continuity** (Eric's check surfaced the outbound gap):
+   the client fill-stamps the `my_cid` tag from context; local deliveries inject
+   the read-only `my_correlation_id` view (WorkerHandler parity);
+   `trace_context()` carries it.
+3. **Span lineage** (Eric: "the lineage documents the graphs" - AI SDLC): every
+   traced execution mints a 16-hex span parented on the caller's (inbound
+   envelope span); outbound events/segments carry the current span (touch
+   parity, traceparent lights up); the engines' `rpc` tag suppresses datasets
+   for RPC legs; non-RPC executions emit the engines' distributed-trace dataset
+   on the `distributed.tracing` stdout stream (message = {"trace": {...},
+   "annotations": {...}} - key-for-key the Java Telemetry record). Sender
+   attribution: the host fills `event.api.service` for anonymous wire callers
+   (Eric's review find); the context carries the executing route for onward
+   calls.
+4. **Application log context** (Eric's follow-on gap): the engines'
+   app-log-context feature - packaged `default-log-context.yaml` (a real
+   resource file, not a code constant - Eric's check), `resources/
+   app-log-context.yaml` override, `app.log.context` flag, `update_context()`
+   developer API with reserved-key guard; a `context` block on json/compact log
+   lines inside traced requests; app log and telemetry join on spanId.
+5. The interop report copy (`docs/test-reports/progressive-rendering-interop.md`)
+   incl. the captured end-to-end telemetry + app-log-context appendix; the
+   streaming guide; the demo `hello.tokens` echoes trace_id + my_correlation_id
+   in eof metadata and logs a context-bearing line.
+
+**Durable lessons:**
+
+- Long-lived bus workers inherit the creating task's contextvars - a stale trace
+  leaked onto telemetry records until workers detach at start (`_set_trace(None)`).
+- The log-context loader is invoked from inside the log formatter: install the
+  resolved config BEFORE emitting its warning, or the loader lock deadlocks.
+- The engines emit trace datasets only for non-RPC executions (WorkerHandler's
+  rpc-tag gate) - parity means suppressing, not enriching.
+- IDE type checkers do not narrow a walrus inside a comprehension filter; a
+  generator + `is not None` two-step narrows cleanly.
+
+Gates at merge: pytest 83/83, ruff clean, basedpyright 0 errors, mkdocs strict;
+live drives against both engines and the node twin recorded in the interop report.
+
+## Memory References
+
+- referenced: bp-publish-interop-gate (substance updated: v4.12.0 merged; PyPI
+  publish still Eric-gated), stack-python-hatchling (version substance 0.1.0 ->
+  4.12.0), ot-vision-bootstrap
+- created: ot-streaming-telemetry-round-20260830 (tier: working)