ci(integration): run the slow tier on eight runners

.github/scripts/slow_test_durations.py

@@ -1,9 +1,10 @@
 """Rewrite tst/integration/slow_durations.json from the slow tier's JUnit reports, so the CI shards stay balanced.
 
-    python .github/scripts/slow_test_durations.py junit-integration-slow-*.xml
+    gh run download <run id> --pattern 'junit-integration-local-*'
+    python .github/scripts/slow_test_durations.py junit-integration-local-*/junit-integration-slow.xml
 
-Download the reports from a green ``main`` run (the ``junit-integration-local-*`` artifacts of every
-``integration-local-slow`` and ``integration-local-gateway`` shard). Each test's time counts toward its file,
+Use a green ``main`` run: it has a ``junit-integration-local-*`` artifact for every ``integration-local-slow`` and
+``integration-local-gateway`` shard, which ``gh run download`` puts in a folder each. Each test's time counts toward its file,
 or toward the test itself for a file the table names in ``split_by_test``; that list is kept as it is.
 """
 

.github/workflows/local-backends.yml

@@ -113,11 +113,11 @@ jobs:
   # (tst/util/shards.py). The gateway tests are a check of their own, split the same way. Each check passes
   # when all of its shards do (the integration-local-slow and integration-local-gateway jobs below).
   integration-local-slow-shard:
-    name: integration-local-slow (${{ matrix.shard }}/4)
+    name: integration-local-slow (${{ matrix.shard }}/8)
     strategy:
       fail-fast: false
       matrix:
-        shard: [1, 2, 3, 4]
+        shard: [1, 2, 3, 4, 5, 6, 7, 8]
     runs-on: ubuntu-latest
     timeout-minutes: 40
     steps:
@@ -140,7 +140,7 @@ jobs:
           timeout 30 sh -c 'until curl -sf http://localhost:5000/v2/ >/dev/null; do sleep 1; done'
       - name: Slow integration tier on the local defaults
         env:
-          AGENTENV_TEST_SHARD: ${{ matrix.shard }}/4
+          AGENTENV_TEST_SHARD: ${{ matrix.shard }}/8
         run: |
           .venv/bin/python -m pytest -m int_test_slow -rA --timeout=1200 --junitxml=junit-integration-slow.xml \
             tst/integration --ignore=tst/integration/env/gateway/gateway_test.py

AGENTS.md

@@ -254,7 +254,8 @@ orchestrators call it the same way. What callers rely on:
   backends. Minutes-long tests (real image builds, sandbox VMs, gateways, agents) carry
   `@pytest.mark.int_test_slow` (or module-level `pytestmark`) and run serially. CI splits them across
   runners instead: `AGENTENV_TEST_SHARD=i/N` (`tst/util/shards.py`) runs the i-th of N groups, keeping a
-  file's tests together and balancing the groups by `tst/integration/slow_durations.json`. When the
+  file's tests together unless the table's `split_by_test` lists the file, and balancing the groups by
+  `tst/integration/slow_durations.json`. When the
   shards' times drift apart, rewrite the table from a `main` run's `junit-integration-local-*`
   artifacts with `.github/scripts/slow_test_durations.py`.
 - `tst/manual/` and `tst/benchmarks/` run only by hand, as each module's docstring says; no CI job
@@ -281,7 +282,7 @@ resolved, and the checks the `main` ruleset requires: `unit`, `integration-local
 pass, but a failing one does not block the merge.
 `.github/workflows/local-backends.yml` runs `unit`, `ui`, `integration-local`, `integration-local-slow`,
 `integration-local-gateway` (the slow tier's `gateway_test.py`, run beside the rest of it) and
-`installer`. The slow tier runs on four runners (`integration-local-slow (1/4)` to `(4/4)`) and the
+`installer`. The slow tier runs on eight runners (`integration-local-slow (1/8)` to `(8/8)`) and the
 gateway tests on two, and `integration-local-slow` and `integration-local-gateway` each pass when all
 of their shards do. The Python jobs install from `uv.lock` (public PyPI only), with the uv that
 `.github/ci-requirements.txt` pins, and use no secrets and no external services (a `registry:2`

Makefile

@@ -45,7 +45,7 @@ unit-test: ## Run the unit test suite in parallel (no external services)
 #   clock but is the only way to keep slow runs reliable without rewriting
 #   every module's fixtures with worker-unique tags. CI splits the slow tier
 #   across runners instead (tst/util/shards.py). To run one runner's share:
-#     AGENTENV_TEST_SHARD=2/4 make int-test-slow PYTEST_ARGS=--ignore=tst/integration/env/gateway/gateway_test.py
+#     AGENTENV_TEST_SHARD=2/8 make int-test-slow PYTEST_ARGS=--ignore=tst/integration/env/gateway/gateway_test.py
 #     AGENTENV_TEST_SHARD=1/2 .venv/bin/python -m pytest -m int_test_slow tst/integration/env/gateway/gateway_test.py
 INT_PYTEST_ARGS_FAST ?= --dist=loadscope --tb=short --durations=20 -p no:cacheprovider
 INT_PYTEST_ARGS_SLOW ?= --tb=short --durations=20 -p no:cacheprovider