diff --git a/noxfile.py b/noxfile.py
index 7cf3e6a9b..01ae1f963 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -313,9 +313,48 @@ def integration_tests(session: nox.Session):
 
 @nox.session(python=SUPPORTED_PYTHONS, reuse_venv=True, venv_backend="uv")
 def slow_integration_tests(session: nox.Session):
-    """Run Robot Framework integration tests."""
+    """Run Robot Framework slow integration tests (parallel via pabot).
+
+    Runs all tests tagged ``slow`` that are excluded from the standard
+    ``integration_tests`` session.  Defaults to conservative parallelism
+    (<=2 processes) to avoid resource pressure in CI.  Override via
+    TEST_PROCESSES or by passing --processes/--processes=N in session
+    arguments.
+    """
     session.install("-e", ".[tests]")
     session.env["CLEVERAGENTS_AUTO_APPLY_MIGRATIONS"] = "true"
+    session.env["NO_COLOR"] = "1"
+    # Override PYTHONPATH so the editable install (src/) for this project
+    # is used instead of any inherited PYTHONPATH from the outer environment.
+    session.env["PYTHONPATH"] = "src"
+
+    # Propagate venv bin to PATH so Run Process in robot files finds
+    # the venv's python/robot rather than the system copies.
+    venv_bin = os.path.join(session.virtualenv.location, "bin")
+    session.env["PATH"] = venv_bin + os.pathsep + os.environ.get("PATH", "")
+
+    # Ensure output directory exists (CI starts with a clean checkout)
+    os.makedirs("build/reports/robot", exist_ok=True)
+
+    # Pass the venv Python path explicitly so Run Process calls use it
+    # instead of relying on PATH (which may not propagate to subprocesses).
+    venv_python = os.path.join(venv_bin, "python")
+
+    # Pre-compile bytecode so that parallel pabot workers (and the
+    # Python sub-processes they spawn via ``Run Python Script``) can
+    # read cached .pyc files instead of each cold-compiling every
+    # module from source simultaneously — avoids a thundering-herd
+    # race on CI runners with high core counts.
+    session.run("python", "-m", "compileall", "-q", "src/")
+
+    # Build a pre-migrated template DB so helper scripts that call
+    # setup_workspace() can copy it instead of running 25+ Alembic
+    # migrations per test — critical for parallel pabot execution.
+    template_path = _create_template_db(session)
+    session.env["CLEVERAGENTS_TEMPLATE_DB"] = template_path
+
+    pabot_args, robot_args = _split_pabot_args(session.posargs)
+    parallel_args = _pabot_parallel_args(pabot_args)
 
     # TDD expected-fail listener — inverts results for @tdd_expected_fail
     # tagged tests and validates TDD tag combinations.
@@ -327,7 +366,9 @@ def slow_integration_tests(session: nox.Session):
     )
 
     session.run(
-        "robot",
+        "pabot",
+        *parallel_args,
+        *pabot_args,
         "--outputdir",
         "build/reports/robot",
         "--loglevel",
@@ -338,12 +379,24 @@ def slow_integration_tests(session: nox.Session):
         "log.html",
         "--xunit",
         "xunit.xml",
+        "--variable",
+        f"PYTHON:{venv_python}",
         "--listener",
         tdd_listener,
+        "--include",
+        "slow",
+        "--exclude",
+        "discovery",
+        "--exclude",
+        "code_blocks",
+        "--exclude",
+        "wip",
+        "--exclude",
+        "E2E",
         "--exclude",
         "tdd_fixture",
+        *robot_args,
         "robot/",
-        *session.posargs,
     )
 
 
@@ -378,6 +431,12 @@ def e2e_tests(session: nox.Session):
     # Pre-compile bytecode to avoid cold-compilation overhead.
     session.run("python", "-m", "compileall", "-q", "src/")
 
+    # Build a pre-migrated template DB so helper scripts that call
+    # setup_workspace() can copy it instead of running 25+ Alembic
+    # migrations per test — reduces per-test setup from ~1-3 s to ~1 ms.
+    template_path = _create_template_db(session)
+    session.env["CLEVERAGENTS_TEMPLATE_DB"] = template_path
+
     # Propagate LLM API keys from the environment into the session
     # so that real E2E tests can authenticate with providers.
     for key in (