diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 93a92f1..73794f5 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -8,7 +8,7 @@ on:
       tag:
         description: Git tag to publish
         required: true
-        default: v0.8.2
+        default: v0.8.3
 
 permissions:
   contents: read
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0c259c8..19657b9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,19 @@
 
 Notable user- and contributor-visible changes are recorded here.
 
+## 0.8.3
+
+### External-pack compatibility and source time
+
+- Add the public conformance seam external packages use to resolve and verify exact installed
+  Domain Packs without importing the private host runtime.
+- Preserve source publication time separately from observation and ingestion time in declarative
+  source mapping, including explicit unknown publication time.
+- Export the durable Intelligence build-host composer through the public Application surface so
+  isolated installed-surface conformance cannot depend on test import order.
+- Carry the merged single-user Builder hardening through active-session first-Brief binding while
+  preserving schema head v177, exactly eleven MCP tools, and the 0.8 compatibility line.
+
 ## 0.8.2
 
 ### Intelligence Catalog and outcome-led onboarding
diff --git a/Dockerfile b/Dockerfile
index 5fb0002..db335c0 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 FROM python:3.12-slim
 
-ARG ACE_VERSION=0.8.2
+ARG ACE_VERSION=0.8.3
 LABEL org.opencontainers.image.title="ace-core" \
       org.opencontainers.image.version="${ACE_VERSION}" \
       org.opencontainers.image.source="https://github.com/augmented-cognition-engine/core"
diff --git a/README.md b/README.md
index 51a3475..c39edba 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ monitors, and an intelligence system that improves with governed feedback. ACE i
 provenance, authority, durable state, and exact receipts stay built into the result instead of
 becoming infrastructure every product team must recreate.
 
-![version 0.8.2](https://img.shields.io/badge/version-0.8.2-blue)
+![version 0.8.3 candidate](https://img.shields.io/badge/version-0.8.3--candidate-blue)
 ![Python 3.12](https://img.shields.io/badge/python-3.12-blue)
 ![License Apache-2.0](https://img.shields.io/badge/license-Apache--2.0-green)
 ![status: developer preview](https://img.shields.io/badge/status-developer%20preview-orange)
@@ -386,7 +386,19 @@ transforms only), `ace.intelligence.personas/v1alpha1` (personas plus signal-rou
 
 ---
 
-## What 0.8.2 adds
+## What 0.8.3 adds
+
+0.8.3 is a compatibility patch for independently packaged Intelligence products. It adds the
+public conformance seam needed to resolve exact installed Domain Packs and preserves source
+publication time separately from observation and ingestion time. Market and other external
+consumers can therefore test the exact installed pack and retain truthful bitemporal provenance
+without importing the private host runtime.
+
+The patch also carries the subsequent single-user Builder hardening already merged on the 0.8
+line. It preserves schema head v177, exactly eleven public MCP tools, the inert Domain Pack
+boundary, and the separately versioned adapter model.
+
+### What 0.8.2 added
 
 0.8.2 makes first use start with the outcome a person wants rather than ACE's internal
 architecture. Atrium discovers every admitted onboarding profile from the governed Intelligence
@@ -858,7 +870,7 @@ stay host-free, and host adapters are the only `core.engine` edge into the publi
 
 ## Maturity and limitations
 
-**0.8.2 is the current published developer preview.** Its Intelligence OS
+**0.8.3 is a release candidate over the published 0.8.2 developer preview.** Its Intelligence OS
 claim is bounded to
 the provider-free and installed-artifact journeys recorded in the evidence archive and the
 single-node topology below. Read this section before you build on it.
diff --git a/ROADMAP.md b/ROADMAP.md
index 7835f2b..b04a41a 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -82,6 +82,10 @@ on PyPI and GitHub. It packages the Atrium Intelligence Catalog as backward-comp
 of the released 0.8 promise. It is the entry foundation for—but does not complete—the 0.9
 Single-user Intelligence Builder milestone.
 
+The current 0.8.3 compatibility release candidate adds the public exact-installed-Pack
+conformance seam and preserves source publication time separately from observation and ingestion
+time. It remains a patch on the released 0.8 promise and does not advance roadmap maturity.
+
 The 0.8 release makes the existing Builder, composition, memory, authority, action, and outcome
 capabilities coherent as one **Intelligence Operating System**. One governed point-in-time resource
 plane exposes the complete evidence → orientation → decision/action → outcome → feedback loop to
diff --git a/ace/__init__.py b/ace/__init__.py
index 53f86a7..bd9c1b4 100644
--- a/ace/__init__.py
+++ b/ace/__init__.py
@@ -1,3 +1,3 @@
 """Public Python package identity for ACE."""
 
-__version__ = "0.8.2"
+__version__ = "0.8.3"
diff --git a/ace/application/__init__.py b/ace/application/__init__.py
index 5acf100..fba5f4d 100644
--- a/ace/application/__init__.py
+++ b/ace/application/__init__.py
@@ -336,6 +336,10 @@
     IntelligenceBuildFirstBriefRequestV1Alpha1,
     IntelligenceBuildFirstBriefRequestV1Alpha2,
 )
+from ace.application.intelligence_build_host import (
+    DurableIntelligenceBuildHostComposer,
+    IntelligenceBuildHostCompositionError,
+)
 from ace.application.intelligence_build_planning import (
     INTELLIGENCE_BUILD_PLAN_REQUEST_V1ALPHA2_VERSION,
     INTELLIGENCE_BUILD_PLAN_REQUEST_VERSION,
@@ -871,6 +875,8 @@
     "IntelligenceBuildEffect",
     "IntelligenceBuildExecutor",
     "IntelligenceBuildFirstBriefPort",
+    "DurableIntelligenceBuildHostComposer",
+    "IntelligenceBuildHostCompositionError",
     "IntelligenceBuildHostServices",
     "IntelligenceBuildPreparedDerivationPort",
     "IntelligenceBuildResourcePagePort",
diff --git a/ace_mcp_client/__init__.py b/ace_mcp_client/__init__.py
index 11e5856..9075eb8 100644
--- a/ace_mcp_client/__init__.py
+++ b/ace_mcp_client/__init__.py
@@ -1,4 +1,4 @@
 # ace_mcp_client — standalone MCP thin client for ACE
 # Zero engine imports. Pure HTTP calls to the ACE API.
 
-__version__ = "0.8.2"
+__version__ = "0.8.3"
diff --git a/core/engine/version.py b/core/engine/version.py
index 6b287d1..8e37945 100644
--- a/core/engine/version.py
+++ b/core/engine/version.py
@@ -1,3 +1,3 @@
 """Single source of truth for the ACE distribution version."""
 
-VERSION = "0.8.2"
+VERSION = "0.8.3"
diff --git a/docs/capability-maturity.md b/docs/capability-maturity.md
index 9bb2078..93843e3 100644
--- a/docs/capability-maturity.md
+++ b/docs/capability-maturity.md
@@ -1,6 +1,6 @@
-# ACE 0.8.2 candidate capability maturity
+# ACE 0.8.3 candidate capability maturity
 
-ACE 0.8.2 is a release candidate over the published 0.8.1 developer preview. This page
+ACE 0.8.3 is a release candidate over the published 0.8.2 developer preview. This page
 distinguishes the public contract from implemented
 surfaces that remain experimental.
 
@@ -13,13 +13,13 @@ install ace-core → configure SurrealDB and an optional provider → start ACE
 → connect → map → watch → receive a cited brief → activate → inspect resources → stop cleanly
 ```
 
-The 0.8.2 candidate identities are:
+The 0.8.3 candidate identities are:
 
 - Python distribution: `ace-core`
 - Python import: `ace`
 - CLI command: `ace`
 - thin MCP command: `ace-mcp-client`
-- version: `0.8.2`
+- version: `0.8.3`
 
 The thin MCP surface contains exactly eleven tools:
 
diff --git a/docs/evidence/README.md b/docs/evidence/README.md
index 1a4b144..949fa58 100644
--- a/docs/evidence/README.md
+++ b/docs/evidence/README.md
@@ -32,6 +32,8 @@ superseded by later work and is kept for audit trail only.
   — public, passed; exact tag, trusted publication, hashes, and checkout-free install
 - [ace-core 0.8.2 Intelligence Catalog release candidate](intelligence-catalog-v0.8.2-release-candidate-v1.md)
   — candidate; artifact, paired-domain, publication, and public-index gates pending
+- [ace-core 0.8.3 external-pack compatibility release candidate](external-pack-compatibility-v0.8.3-release-candidate-v1.md)
+  — candidate; exact-pack, semantic-time, artifact, publication, and public-index gates pending
 - [ace-core 0.8.0 Intelligence OS release candidate](intelligence-os-v0.8.0-release-candidate-v1.md)
   — historical pre-publication candidate; cumulative Core, Atrium, World, Market, and package gate
 
diff --git a/docs/evidence/external-pack-compatibility-v0.8.3-release-candidate-v1.md b/docs/evidence/external-pack-compatibility-v0.8.3-release-candidate-v1.md
new file mode 100644
index 0000000..455e46a
--- /dev/null
+++ b/docs/evidence/external-pack-compatibility-v0.8.3-release-candidate-v1.md
@@ -0,0 +1,50 @@
+# ACE 0.8.3 external-pack compatibility release candidate
+
+Status: **candidate — artifact, publication, and public-index gates pending**
+
+## Promise
+
+ACE 0.8.3 lets independently packaged Intelligence products verify the exact installed Domain
+Pack through a public conformance seam and retain source publication time separately from
+observation and ingestion time. The patch exists to remove version skew between Core and external
+pack conformance without exposing the private host runtime or changing the 0.8 product promise.
+
+## Candidate coordinates
+
+- source base: Core main merge `1fe2d3c0759d42aebd057018ebf00aa6d2178f3b`;
+- release branch: `codex/v083-compat-release`;
+- candidate distribution: `ace-core==0.8.3`;
+- required compatibility merges: `94b55c2` (#166) and `08f8419` (#170);
+- schema head: v177;
+- public MCP surface: exactly eleven tools;
+- reference action adapter: unchanged distribution 0.4.0 with `ace-core>=0.8.0,<0.9`.
+
+## Included changes
+
+1. `ace.intelligence.conformance` resolves and verifies exact installed pack material for external
+   consumer tests without a private `core.engine` import.
+2. Declarative source mapping preserves nullable publication time independently from observed and
+   ingested time.
+3. The durable Intelligence build-host composer is loaded and exported by the public Application
+   package, including in an isolated installed-surface conformance run.
+4. Subsequent merged Builder hardening through active-session first-Brief binding remains on the
+   same schema, MCP, authority, and separately installed adapter boundaries.
+
+## Required acceptance before publication
+
+- Core lint, fast tests, naked-kernel, Canvas, security, and Docker gates pass at the exact
+  candidate head.
+- Package identity, roadmap positioning, evidence-index, conformance, source-mapping, and
+  build-backend gates pass.
+- The wheel and sdist build reproducibly, pass strict Twine validation, install outside the
+  checkout, report 0.8.3, import the public conformance seam, preserve semantic source time, and
+  expose exactly eleven MCP tools.
+- The Market consumer can then pin the public 0.8.3 artifact, regenerate only its current
+  candidate artifacts, and preserve every frozen historical release packet.
+
+## Boundaries
+
+This patch does not claim a universal connector catalog, collaborative multi-tenancy, hostile-code
+isolation, distributed operation, autonomous source authorization, arbitrary web access,
+autonomous publication, general real-world causal accuracy, or general beneficial impact. It does
+not advance roadmap maturity or complete the 0.9 or 1.0 release gates.
diff --git a/docs/faq.md b/docs/faq.md
index aab8cfb..e0d471c 100644
--- a/docs/faq.md
+++ b/docs/faq.md
@@ -4,7 +4,7 @@ This FAQ answers the operational questions that tend to appear after the archite
 what happens when part of a committee fails, how conflicting claims are handled, what confidence
 means, and how multiple products share SurrealDB without becoming one undifferentiated memory.
 
-ACE 0.8.2 is a release candidate over the published 0.8.1 developer preview. Answers below
+ACE 0.8.3 is a release candidate over the published 0.8.2 developer preview. Answers below
 distinguish the supported Intelligence OS contract
 from broader engine capabilities whose APIs and end-to-end journeys remain experimental. See
 [capability maturity](capability-maturity.md) for the authoritative boundary and
@@ -370,7 +370,7 @@ end-to-end operating journeys remain experimental in 0.8.
 
 ### What is the stable public contract today?
 
-ACE 0.8.2 is a developer-preview release candidate: the self-hosted CLI, exactly eleven thin MCP tools,
+ACE 0.8.3 is a developer-preview release candidate: the self-hosted CLI, exactly eleven thin MCP tools,
 documented provider routes, schema migrations, public Core/Intelligence/Application packages,
 inert Domain Pack boundary, and authorized Intelligence resource plane. Atrium is a supported,
 optional repository-delivered preview over that same plane; it is not included in the Python
diff --git a/extensions/reference/extension.py b/extensions/reference/extension.py
index dc64c11..739e25a 100644
--- a/extensions/reference/extension.py
+++ b/extensions/reference/extension.py
@@ -56,7 +56,7 @@ class ProductExtension:
     """The open `product` extension — copy this file to start your own."""
 
     name = "product"
-    version = "0.8.2"
+    version = "0.8.3"
 
     def register(self, reg: "Registry") -> None:
         # This must remain the first operation. A current reference extension
diff --git a/infra/docker-compose.yml b/infra/docker-compose.yml
index c4fe70c..1793f67 100644
--- a/infra/docker-compose.yml
+++ b/infra/docker-compose.yml
@@ -40,7 +40,7 @@ services:
       context: ..
       dockerfile: Dockerfile
       args:
-        ACE_VERSION: "0.8.2"
+        ACE_VERSION: "0.8.3"
     depends_on:
       surrealdb:
         condition: service_healthy
@@ -61,9 +61,9 @@ services:
       context: ..
       dockerfile: Dockerfile
       args:
-        ACE_VERSION: "0.8.2"
+        ACE_VERSION: "0.8.3"
     labels:
-      org.opencontainers.image.version: "0.8.2"
+      org.opencontainers.image.version: "0.8.3"
     depends_on:
       surrealdb:
         condition: service_healthy
@@ -98,9 +98,9 @@ services:
       context: ..
       dockerfile: Dockerfile
       args:
-        ACE_VERSION: "0.8.2"
+        ACE_VERSION: "0.8.3"
     labels:
-      org.opencontainers.image.version: "0.8.2"
+      org.opencontainers.image.version: "0.8.3"
     depends_on:
       surrealdb:
         condition: service_healthy
diff --git a/pyproject.toml b/pyproject.toml
index c599bcd..7af349b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "ace-core"
-version = "0.8.2"
+version = "0.8.3"
 description = "Open Intelligence Operating System with a guided Intelligence Builder"
 readme = "README.md"
 license = "Apache-2.0"
diff --git a/tests/test_package_identity.py b/tests/test_package_identity.py
index 9ceddfa..b799c9e 100644
--- a/tests/test_package_identity.py
+++ b/tests/test_package_identity.py
@@ -20,7 +20,7 @@ def test_distribution_import_cli_and_version_identities() -> None:
     project = tomllib.loads((ROOT / "pyproject.toml").read_text(encoding="utf-8"))["project"]
 
     assert project["name"] == "ace-core"
-    assert project["version"] == ace.__version__ == ace_mcp_client.__version__ == VERSION == "0.8.2"
+    assert project["version"] == ace.__version__ == ace_mcp_client.__version__ == VERSION == "0.8.3"
     assert ProductExtension.version == project["version"]
     assert project["scripts"]["ace"] == "core.engine.cli.main:cli"
     assert "aiohttp>=3.14.3" in project["dependencies"]
@@ -43,7 +43,7 @@ def test_package_copy_and_public_links_are_release_ready() -> None:
 def test_release_workflow_defaults_to_and_guards_current_version() -> None:
     workflow = (ROOT / ".github" / "workflows" / "publish.yml").read_text(encoding="utf-8")
 
-    assert "default: v0.8.2" in workflow
+    assert "default: v0.8.3" in workflow
     assert "Validate release tag matches package version" in workflow
     assert 'if [ "$RELEASE_TAG" != "v$package_version" ]' in workflow
     assert "ace-core-python-distributions" in workflow
@@ -58,13 +58,13 @@ def test_release_workflow_defaults_to_and_guards_current_version() -> None:
 def test_docker_image_includes_public_cli_package() -> None:
     dockerfile = (ROOT / "Dockerfile").read_text(encoding="utf-8")
     assert "COPY ace/ ace/" in dockerfile
-    assert "ARG ACE_VERSION=0.8.2" in dockerfile
+    assert "ARG ACE_VERSION=0.8.3" in dockerfile
     assert 'org.opencontainers.image.version="${ACE_VERSION}"' in dockerfile
     assert "uv sync --frozen --no-dev --no-editable --no-cache" in dockerfile
 
     compose = (ROOT / "infra" / "docker-compose.yml").read_text(encoding="utf-8")
-    assert compose.count('ACE_VERSION: "0.8.2"') == 3
-    assert compose.count('org.opencontainers.image.version: "0.8.2"') == 2
+    assert compose.count('ACE_VERSION: "0.8.3"') == 3
+    assert compose.count('org.opencontainers.image.version: "0.8.3"') == 2
 
 
 def test_lock_tracks_the_distribution_identity() -> None:
diff --git a/tests/test_public_roadmap_positioning.py b/tests/test_public_roadmap_positioning.py
index 73ccdd3..fac7fce 100644
--- a/tests/test_public_roadmap_positioning.py
+++ b/tests/test_public_roadmap_positioning.py
@@ -5,7 +5,8 @@
 ROADMAP = (Path(__file__).resolve().parents[1] / "ROADMAP.md").read_text(encoding="utf-8")
 ROADMAP_ONE_LINE = " ".join(ROADMAP.split())
 
-# The current-release assertions preserve the bounded published 0.8.2 patch. Historical 0.4.1 GI2,
+# The current-release assertions preserve published 0.8.2 while admitting the bounded 0.8.3
+# compatibility candidate. Historical 0.4.1 GI2,
 # 0.4.2 builder-surface, 0.4.4 GC1, 0.5.0 T1/B1, and P1/P2 identities remain exact point-in-time
 # evidence. Keep these aligned with test_evidence_index_integrity.py.
 
@@ -13,6 +14,7 @@
 def test_current_release_and_passed_milestone_are_not_conflated() -> None:
     assert "latest published release is [`ace-core` 0.8.2]" in ROADMAP
     assert "passed 0.8.2 patch adds the Atrium Intelligence Catalog" in ROADMAP
+    assert "current 0.8.3 compatibility release candidate" in ROADMAP
     assert ROADMAP.count("| 0.4.x | Governed Cognition | **Passed** |") == 1
     assert "| 0.4.0 | Governed Cognition | **Delivered** |" not in ROADMAP
     assert "| 0.4.0 | Governed Cognition | **Now** |" not in ROADMAP
@@ -20,7 +22,7 @@ def test_current_release_and_passed_milestone_are_not_conflated() -> None:
     assert "| 0.6.0 | Measured Intelligence | **Passed** |" in ROADMAP
     assert "| 0.7.0 | Intelligence Builder Foundation | **Passed** |" in ROADMAP
     readme = (Path(__file__).resolve().parents[1] / "README.md").read_text(encoding="utf-8")
-    assert "0.8.2 is the current published developer preview" in " ".join(readme.split())
+    assert "0.8.3 is a release candidate over the published 0.8.2 developer preview" in " ".join(readme.split())
     assert "| 0.8.0 | Intelligence OS Realignment | **Passed** |" in ROADMAP
     assert "| 0.9.0 | Single-user Intelligence Builder | **Now** |" in ROADMAP
     assert "| 1.0.0 | Personal Intelligence Operating System | **Next** |" in ROADMAP
diff --git a/uv.lock b/uv.lock
index 74e85f2..89a58a3 100644
--- a/uv.lock
+++ b/uv.lock
@@ -4,7 +4,7 @@ requires-python = "==3.12.*"
 
 [[package]]
 name = "ace-core"
-version = "0.8.2"
+version = "0.8.3"
 source = { editable = "." }
 dependencies = [
     { name = "aiohttp" },