diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index ca832487b..eeadc112c 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -109,3 +109,4 @@ Below are some specific details of individual PR contributions.
 * HAL 9000 has contributed the CleanupService sandbox cache invalidation fix (PR #8257 / issue #7527): `_purge_sandboxes()` now invalidates the internal `_sandbox_dirs_cache` after deleting stale directories so that a subsequent `scan()` call on the same instance re-reads the filesystem instead of returning already-deleted paths as stale items.
 * HAL 9000 has contributed the LSP subprocess cleanup fix (#10597): added a defensive ``_process = None`` reset before ``subprocess.Popen()`` in ``StdioTransport.start()`` to prevent orphaned child processes and file descriptor leaks when ``subprocess.Popen()`` fails during initialization.
 * HAL 9000 has contributed the Invariant Data Model and Database Schema (PR #8701 / issue #8524): SQLAlchemy ORM model with fields id (UUID), description (text), created_at (timestamp), and is_active (bool); Alembic migration creating the invariants table with index on is_active for efficient active-query filtering; BDD Behave unit tests and Robot Framework integration tests.
+* HAL 9000 has contributed the ACMS execute phase ContextAssemblyPipeline wiring (PR #10027): replaces the base ``ACMSPipeline`` default with ``ContextAssemblyPipeline`` in ``ACMSExecutePhaseContextAssembler``, enabling production Phase 1 components (confidence-weighted strategy selection, proportional budget allocation, parallel execution with circuit breaking) and per-stage timing instrumentation by default. Includes Behave test coverage verifying the default pipeline type.
diff --git a/features/execute_phase_context_assembler_coverage.feature b/features/execute_phase_context_assembler_coverage.feature
index 660a79392..3e9ad7ec0 100644
--- a/features/execute_phase_context_assembler_coverage.feature
+++ b/features/execute_phase_context_assembler_coverage.feature
@@ -275,3 +275,13 @@ Feature: Execute-phase context assembler coverage
     And epcov scoped fragments that pass all filters
     When epcov I call assemble on the plan
     Then epcov the pipeline received budget max_tokens of 4096
+
+  # ---- Default pipeline type ----
+
+  Scenario: epcov default pipeline is ContextAssemblyPipeline when none provided
+    Given epcov an assembler with no explicit pipeline argument
+    Then epcov the internal pipeline should be a ContextAssemblyPipeline
+
+  Scenario: epcov explicit pipeline overrides default ContextAssemblyPipeline
+    Given epcov an assembler with an explicitly passed ACMSPipeline mock
+    Then epcov the internal pipeline should be the explicitly passed mock
diff --git a/features/steps/execute_phase_context_assembler_coverage_steps.py b/features/steps/execute_phase_context_assembler_coverage_steps.py
index 53a0ddf2d..68ac3e0d3 100644
--- a/features/steps/execute_phase_context_assembler_coverage_steps.py
+++ b/features/steps/execute_phase_context_assembler_coverage_steps.py
@@ -19,6 +19,9 @@ from unittest.mock import MagicMock, patch
 from behave import given, then, when
 from behave.runner import Context
 
+from cleveragents.application.services.acms_pipeline import (
+    ContextAssemblyPipeline,
+)
 from cleveragents.application.services.execute_phase_context_assembler import (
     ACMSExecutePhaseContextAssembler,
 )
@@ -124,6 +127,61 @@ def _make_assembler(
     return assembler
 
 
+@given("epcov an assembler with no explicit pipeline argument")
+def step_epcov_no_explicit_pipeline(context: Context) -> None:
+
+    tier_service = MagicMock()
+    tier_service.get_scoped_view.return_value = []
+
+    repo = MagicMock()
+    repo.get_context_policy.return_value = ProjectContextPolicy()
+
+    context.epcov_assembler = ACMSExecutePhaseContextAssembler(
+        context_tier_service=tier_service,
+        project_repository=repo,
+        hot_max_tokens=4096,
+    )
+
+
+@given("epcov an assembler with an explicitly passed ACMSPipeline mock")
+def step_epcov_explicit_pipeline(context: Context) -> None:
+
+    tier_service = MagicMock()
+    tier_service.get_scoped_view.return_value = []
+
+    repo = MagicMock()
+    repo.get_context_policy.return_value = ProjectContextPolicy()
+
+    mock_pipeline = MagicMock()
+    context.epcov_explicit_pipeline_mock = mock_pipeline
+    context.epcov_assembler = ACMSExecutePhaseContextAssembler(
+        context_tier_service=tier_service,
+        project_repository=repo,
+        acms_pipeline=mock_pipeline,
+        hot_max_tokens=4096,
+    )
+
+
+@then("epcov the internal pipeline should be a ContextAssemblyPipeline")
+def step_epcov_default_pipeline_is_context_assembly(context: Context) -> None:
+
+    assert isinstance(
+        context.epcov_assembler._pipeline,
+        ContextAssemblyPipeline,
+    ), (
+        f"Expected ContextAssemblyPipeline but got "
+        f"{type(context.epcov_assembler._pipeline).__name__}"
+    )
+
+
+@then("epcov the internal pipeline should be the explicitly passed mock")
+def step_epcov_explicit_pipeline_kept(context: Context) -> None:
+
+    assert context.epcov_assembler._pipeline is context.epcov_explicit_pipeline_mock, (
+        "Expected the explicitly passed mock pipeline to be used"
+    )
+
+
 # ---------------------------------------------------------------------------
 # Protocol (line 36)
 # ---------------------------------------------------------------------------
diff --git a/src/cleveragents/application/services/execute_phase_context_assembler.py b/src/cleveragents/application/services/execute_phase_context_assembler.py
index da2af9895..17f5fdbb9 100644
--- a/src/cleveragents/application/services/execute_phase_context_assembler.py
+++ b/src/cleveragents/application/services/execute_phase_context_assembler.py
@@ -9,6 +9,9 @@ from typing import Any, Protocol
 
 import structlog
 
+from cleveragents.application.services.acms_pipeline import (
+    ContextAssemblyPipeline,
+)
 from cleveragents.application.services.acms_service import ACMSPipeline
 from cleveragents.domain.models.acms.crp import AssembledContext, ContextRequest
 from cleveragents.domain.models.acms.tiers import TieredFragment
@@ -49,7 +52,7 @@ class ACMSExecutePhaseContextAssembler(ExecutePhaseContextAssembler):
     ) -> None:
         self._tier = context_tier_service
         self._project_repository = project_repository
-        self._pipeline = acms_pipeline or ACMSPipeline()
+        self._pipeline = acms_pipeline or ContextAssemblyPipeline()
         self._hot_max_tokens = hot_max_tokens
         self._logger = logger.bind(component="execute_phase_context_assembler")