diff --git a/CHANGELOG.md b/CHANGELOG.md
index d850fc78..c7043ddc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). The
 
 ## [Unreleased]
 
+## [0.12.0] — 2026-06-05
+
+Observability release. The pinned spec advances from v0.38.0 to v0.46.0, absorbing eight accepted proposals (0047-0054). Three ship as fully implemented this cycle: proposal 0048 grows a read-symmetric `get_invocation_metadata()` API + a §9 *Queryable observer pattern* concept doc section; proposal 0052 puts `openarmature.implementation.name` + `.version` attribution attributes on every OTel invocation span + every Langfuse Trace; proposal 0054 ships `CompiledGraph.drain_events_for(invocation_id, *, timeout)` as the architectural pair to 0048's §9.4 accumulator lifecycle. Two ship as textual-only acks (0051 Langfuse trace I/O caveat; 0053 §3.4 shared-parent boundary clarification). One Fixed: the retry middleware now resets the invocation-metadata ContextVar between attempts per §3.4. The production-observability example grows the queryable accumulator + drain_events_for pattern end-to-end so the new APIs have a runnable demo.
+
 ### Changed
 
 - **Pinned spec advanced from v0.38.0 to v0.46.0.** Submodule + `[tool.openarmature].spec_version` + `conformance.toml` `spec_pin` advance together. Absorbs eight new proposals (0047-0054) into the conformance manifest. Two ship as textual-only acknowledgments with no code change required: **proposal 0051** (observability §8.4.1 Langfuse `trace.input` / `trace.output` implementation-surface caveat — documents that vendor SDK round-trip is required to project caller-side trace I/O updates onto the wire; the v0.11.0 (proposal 0043) caller-hook shape already matches the documented behavior) and **proposal 0053** (observability §3.4 shared-parent boundary clarification — tightens the structural-shared-parent classification to predicate the invocation span on whether at least one fan-out or parallel-branches dispatch is on the augmenter's call-stack path; behavior already matches via fixtures 034 + 039). Three ship as fully implemented this cycle: **proposal 0048** (read-symmetric metadata + queryable observer pattern docs — see *Added* below), **proposal 0052** (implementation attribution attributes — see *Added* below), and **proposal 0054** (per-invocation observer event drain — see *Added* below; bundled with 0048 as the §9.4 accumulator-lifecycle pair). The remaining proposals are marked `not-yet` in the conformance manifest with roadmap targets: 0047 + 0049 (v0.13.0 LLM provider hardening batch) and 0050 (v0.14.0 retry & reliability batch).
@@ -20,7 +24,7 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). The
 - **`CompiledGraph.drain_events_for(invocation_id, *, timeout=5.0) -> DrainSummary`** (proposal 0054, spec graph-engine §6 *Per-invocation drain*, v0.46.0). The architectural pair to proposal 0048's §9.4 queryable observer accumulator lifecycle: a terminal node calling `await graph.drain_events_for(state.invocation_id)` blocks until every event dispatched for that invocation has reached every attached observer, typically followed by a read against a queryable observer accumulator whose bucket the drain has now caught up to. Snapshot semantic: the drain awaits the events dispatched as of call time; new emissions after the call are out of scope. Reuses the existing `DrainSummary` shape verbatim — no new `InvocationDrainSummary` variant. **Load-bearing divergence from `drain()`**: a per-invocation drain timeout MUST NOT cancel the delivery worker, in contrast to `drain()`'s shutdown semantics. The graph stays serving other invocations after the timeout fires; the deliver loop keeps processing the queue. Default timeout is `5.0` seconds; `None` waits indefinitely; `0.0` is a non-blocking check. Negative or `NaN` timeout raises `ValueError` at the API boundary. Unknown `invocation_id` (already drained or never started) returns an empty summary, not an error.
 - **`get_invocation_metadata()` read-symmetric API** (proposal 0048, observability §3.4, spec v0.40.0). The canonical spec-idiomatic public name for the §3.4 read access pairs with `set_invocation_metadata()` on the write side: same function object as the historical `current_invocation_metadata`, exposed for callers wishing to use the symmetric `get_/set_` naming. Returns the `MappingProxyType` snapshot of the current async context's view (caller baseline + in-node augments), or the empty mapping outside any active invocation. Read-only — callers MUST NOT mutate it. Both names are now exported from `openarmature.observability`; existing `current_invocation_metadata` callers continue to work unchanged.
 - **`docs/concepts/observability.md` §9 *Queryable observer pattern*** documents the convention-only observer-attached read methods that proposal 0048 §9 blesses: how to add a `get_*` read method to a custom observer (§9.1), the async-safety contract for concurrent reads under in-flight delivery (§9.2), the three-channel data-access guidance (typed State / untyped invocation metadata / queryable observer accumulator, §9.3, with a side-by-side table), and the lifecycle / explicit `drop(invocation_id)` discipline (§9.4). No new abstract surface on `Observer` per the spec — the pattern is convention-only and exists to bless the existing observer-state read shape used in production code.
-- **Production observability example.** `examples/production-observability/` demonstrates the production-grade observability stack end-to-end: `OTelObserver` + `LangfuseObserver` attached to the same graph (proposal 0031), `trace_input_from_state` / `trace_output_from_state` caller hooks on the Langfuse observer (proposal 0043 §8.4.1) deriving domain dicts from State, the built-in `TimingMiddleware` recording per-node duration via an `on_complete` callback, and `invoke(metadata={...})` carrying multi-tenant identifiers (tenantId / requestId / featureFlag) that both observers pick up at once. `InMemoryLangfuseClient` + `InMemorySpanExporter` capture in-process so the demo prints what each backend would have ingested without needing real production credentials.
+- **Production observability example.** `examples/production-observability/` demonstrates the production-grade observability stack end-to-end: `OTelObserver` + `LangfuseObserver` attached to the same graph (proposal 0031), `trace_input_from_state` / `trace_output_from_state` caller hooks on the Langfuse observer (proposal 0043 §8.4.1) deriving domain dicts from State, the built-in `TimingMiddleware` recording per-node duration via an `on_complete` callback, and `invoke(metadata={...})` carrying multi-tenant identifiers (tenantId / requestId / featureFlag) that both observers pick up at once. `InMemoryLangfuseClient` + `InMemorySpanExporter` capture in-process so the demo prints what each backend would have ingested without needing real production credentials. The v0.12.0 cycle extends the demo with a third observer: an `LlmUsageAccumulator` queryable-accumulator pattern subscribing to LLM-namespace events, accumulating per-invocation token totals keyed by `current_invocation_id()`, and a terminal `persist` node that calls `await graph.drain_events_for(current_invocation_id(), timeout=2.0)` to synchronize on the deliver loop before reading the bucket and dropping it. The accumulator's `__call__` handles `InvocationCompletedEvent` as a backstop so a drain timeout doesn't leak buckets. The example's OTel formatter also surfaces the root `openarmature.invocation` span with its proposal 0052 implementation attribution attributes alongside the per-node spans.
 - **Chat-with-multimodal example.** `examples/chat-with-multimodal/` demonstrates `ChatPrompt` + `PlaceholderSegment` (proposal 0046) end-to-end: a four-turn lunar-mission Q&A conversation with conversation memory threaded through state, one mid-conversation turn attaching a photograph via `ImageURLBlockTemplate`, the agent processing the multimodal turn naturally without changing the chat-history shape. Complementary to the tool-use example; chat history threading and tool calling are separate primitives.
 - **`docs/examples/index.md` catalog now lists the langfuse-observability example.** A pre-existing gap (it was missing from the catalog) caught and fixed alongside the chat-with-multimodal entry.
 - **PyPI + spec-version shields on the docs homepage.** `docs/index.md` now carries dynamic shields for the published PyPI version and the pinned spec version, sourced from `img.shields.io`. Both auto-update on every publish or spec bump; no maintenance burden. Mirrors the same shield URLs the README already uses.
diff --git a/pyproject.toml b/pyproject.toml
index 369aa111..c74bdaef 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "openarmature"
-version = "0.11.0"
+version = "0.12.0rc1"
 description = "Workflow framework for LLM pipelines and tool-calling agents."
 readme = "README.md"
 requires-python = ">=3.12"
diff --git a/src/openarmature/AGENTS.md b/src/openarmature/AGENTS.md
index ad39275f..b2add674 100644
--- a/src/openarmature/AGENTS.md
+++ b/src/openarmature/AGENTS.md
@@ -1,6 +1,6 @@
 # OpenArmature — Agent documentation
 
-*This is the agent guide bundled with the openarmature Python package, version 0.11.0 (spec v0.46.0). For the full docs site see [openarmature.ai](https://openarmature.ai). For the canonical spec text see [openarmature.org/capabilities](https://openarmature.org/capabilities/). For project-specific conventions for the code you're editing, see the host project's `AGENTS.md` or `CLAUDE.md`.*
+*This is the agent guide bundled with the openarmature Python package, version 0.12.0rc1 (spec v0.46.0). For the full docs site see [openarmature.ai](https://openarmature.ai). For the canonical spec text see [openarmature.org/capabilities](https://openarmature.org/capabilities/). For project-specific conventions for the code you're editing, see the host project's `AGENTS.md` or `CLAUDE.md`.*
 
 ## TL;DR
 
diff --git a/src/openarmature/__init__.py b/src/openarmature/__init__.py
index dd208399..08cffc43 100644
--- a/src/openarmature/__init__.py
+++ b/src/openarmature/__init__.py
@@ -24,7 +24,7 @@
    sessions opening the project find the bundled docs automatically.
 """
 
-__version__ = "0.11.0"
+__version__ = "0.12.0rc1"
 __spec_version__ = "0.46.0"
 # Proposal 0052 (spec observability §5.1 / §8.4.1): canonical
 # package-registry name for this implementation. Surfaces on every
diff --git a/tests/test_smoke.py b/tests/test_smoke.py
index d7899813..5bebcfe4 100644
--- a/tests/test_smoke.py
+++ b/tests/test_smoke.py
@@ -8,7 +8,7 @@
 
 
 def test_package_versions() -> None:
-    assert openarmature.__version__ == "0.11.0"
+    assert openarmature.__version__ == "0.12.0rc1"
     assert openarmature.__spec_version__ == "0.46.0"
 
 
diff --git a/uv.lock b/uv.lock
index fec88505..dad32165 100644
--- a/uv.lock
+++ b/uv.lock
@@ -925,7 +925,7 @@ wheels = [
 
 [[package]]
 name = "openarmature"
-version = "0.11.0"
+version = "0.12.0rc1"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },