diff --git a/.agents/skills/sdk-ci-triage/SKILL.md b/.agents/skills/sdk-ci-triage/SKILL.md
index ddb2f270..b1b57953 100644
--- a/.agents/skills/sdk-ci-triage/SKILL.md
+++ b/.agents/skills/sdk-ci-triage/SKILL.md
@@ -34,13 +34,14 @@ Read when relevant:
 
 - `lint`: pre-commit diff-based checks
 - `ensure-pinned-actions`: workflow hygiene
+- `static_checks`: Ubuntu-only Python matrix for `pylint` and `test_types`
 - `smoke`: install/import matrix across Python and OS
 - `nox`: provider and core test matrix, sharded through `py/scripts/nox-matrix.py`
 - `adk-py`: reusable workflow for ADK coverage
 - `langchain-py`: reusable workflow for LangChain coverage
 - `upload-wheel`: build wheel sanity check
 
-The most common failure source is the `nox` matrix job.
+The most common failure source is still the `nox` matrix job, but `pylint` and `test_types` failures now surface through `static_checks`, not through `nox`.
 
 ## Standard Workflow
 
@@ -48,15 +49,17 @@ The most common failure source is the `nox` matrix job.
 2. Inspect the failing job logs with `gh`.
 3. Determine which workflow branch failed:
    - `lint`
+   - `static_checks`
    - `smoke`
    - `nox`
    - reusable workflow (`adk-py`, `langchain-py`)
    - `upload-wheel`
 4. For `nox` failures, map the matrix job to the exact nox session and pinned provider version from the logs.
-5. Reproduce the narrowest failing command locally.
-6. Fix the bug.
-7. Re-run the narrowest failing command first.
-8. Expand only if shared code changed.
+5. For `static_checks` failures, identify whether `pylint` or `test_types` failed under the reported Python version.
+6. Reproduce the narrowest failing command locally.
+7. Fix the bug.
+8. Re-run the narrowest failing command first.
+9. Expand only if shared code changed.
 
 Do not start by running the whole suite locally unless the failure genuinely spans many sessions.
 
@@ -94,25 +97,29 @@ gh api repos/braintrustdata/braintrust-sdk-python/actions/jobs/<job-id>/logs
 Job names look like this:
 
 ```text
-nox (3.10, ubuntu-latest, 0)
+nox (3.10, ubuntu-24.04, 0)
 ```
 
 That means:
 
 - Python `3.10`
-- OS `ubuntu-latest`
+- OS `ubuntu-24.04`
 - shard `0` out of 4
 
 The workflow runs:
 
 ```bash
-mise exec python@<python-version> -- python ./py/scripts/nox-matrix.py <shard> 4
+mise exec python@<python-version> -- python ./py/scripts/nox-matrix.py <shard> 4 \
+  --exclude-session pylint \
+  --exclude-session test_types
 ```
 
 Use a dry run first to see which sessions belong to the shard:
 
 ```bash
-mise exec python@3.10 -- python ./py/scripts/nox-matrix.py 0 4 --dry-run
+mise exec python@3.10 -- python ./py/scripts/nox-matrix.py 0 4 --dry-run \
+  --exclude-session pylint \
+  --exclude-session test_types
 ```
 
 Then inspect the failing logs to find the exact session name, for example:
@@ -161,6 +168,23 @@ make lint
 make pylint
 ```
 
+### `static_checks`
+
+The `static_checks` job is an Ubuntu-only Python matrix that runs `pylint` and `test_types` together for each configured Python version.
+
+Local equivalents:
+
+```bash
+mise exec python@3.10 -- nox -f ./py/noxfile.py -s pylint test_types
+```
+
+If only one of the two sessions failed in CI, narrow locally to that specific session:
+
+```bash
+mise exec python@3.10 -- nox -f ./py/noxfile.py -s pylint
+mise exec python@3.10 -- nox -f ./py/noxfile.py -s test_types
+```
+
 ### `smoke`
 
 The smoke job validates install + import across OS and Python versions.
@@ -276,7 +300,9 @@ Preferred progression:
 
 ```bash
 # 1. Inspect the failing shard
-mise exec python@3.10 -- python ./py/scripts/nox-matrix.py 0 4 --dry-run
+mise exec python@3.10 -- python ./py/scripts/nox-matrix.py 0 4 --dry-run \
+  --exclude-session pylint \
+  --exclude-session test_types
 
 # 2. Reproduce the exact session
 cd py
@@ -299,7 +325,7 @@ When answering a CI-triage question, report:
 Good example structure:
 
 ```text
-The failing job is `nox (3.10, ubuntu-latest, 0)`.
+The failing job is `nox (3.10, ubuntu-24.04, 0)`.
 Within that shard, the failing session is `test_google_genai(1.30.0)`.
 The root cause is that the tests import a symbol that does not exist in google-genai 1.30.0, even though it exists in newer versions.
 You can reproduce it locally with `cd py && nox -s "test_google_genai(1.30.0)"`.
@@ -311,6 +337,7 @@ The fix is to gate the behavior for older versions or stop assuming the newer AP
 Avoid these common mistakes:
 
 - guessing the session from the provider name without checking `py/noxfile.py`
+- forgetting that CI excludes `pylint` and `test_types` from the sharded `nox` job
 - reproducing with `latest` when CI failed on an older pinned version
 - running from repo root when the real SDK command belongs in `py/`
 - fixing the symptom in tests without understanding the provider-version contract
diff --git a/.github/workflows/adk-py-test.yaml b/.github/workflows/adk-py-test.yaml
index adbfa294..85a4d832 100644
--- a/.github/workflows/adk-py-test.yaml
+++ b/.github/workflows/adk-py-test.yaml
@@ -9,7 +9,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     timeout-minutes: 15
 
     steps:
diff --git a/.github/workflows/checks.yaml b/.github/workflows/checks.yaml
index 4d4b1812..0f373e77 100644
--- a/.github/workflows/checks.yaml
+++ b/.github/workflows/checks.yaml
@@ -10,7 +10,7 @@ permissions:
 
 jobs:
   lint:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     timeout-minutes: 10
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
@@ -26,13 +26,31 @@ jobs:
           mise exec -- pre-commit run --from-ref origin/${{ github.base_ref || 'main' }} --to-ref HEAD
 
   ensure-pinned-actions:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     timeout-minutes: 5
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
       - name: Ensure SHA pinned actions
         uses: zgosalvez/github-actions-ensure-sha-pinned-actions@70c4af2ed5282c51ba40566d026d6647852ffa3e # v5.0.1
 
+  static_checks:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 20
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
+      - name: Setup Python environment
+        uses: ./.github/actions/setup-python-env
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Run pylint and type tests
+        shell: bash
+        run: |
+          mise exec python@${{ matrix.python-version }} -- nox -f ./py/noxfile.py -s pylint test_types
+
   smoke:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
@@ -41,7 +59,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-        os: [ubuntu-latest, windows-latest]
+        os: [ubuntu-24.04, windows-2025]
 
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
@@ -66,7 +84,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-        os: [ubuntu-latest, windows-latest]
+        os: [ubuntu-24.04, windows-2025]
         shard: [0, 1, 2, 3]
 
     steps:
@@ -78,7 +96,9 @@ jobs:
       - name: Run nox tests (shard ${{ matrix.shard }}/4)
         shell: bash
         run: |
-          mise exec python@${{ matrix.python-version }} -- python ./py/scripts/nox-matrix.py ${{ matrix.shard }} 4
+          mise exec python@${{ matrix.python-version }} -- python ./py/scripts/nox-matrix.py ${{ matrix.shard }} 4 \
+            --exclude-session pylint \
+            --exclude-session test_types
 
   adk-py:
     uses: ./.github/workflows/adk-py-test.yaml
@@ -90,7 +110,7 @@ jobs:
     needs:
       - smoke
       - nox
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     timeout-minutes: 10
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
@@ -114,12 +134,13 @@ jobs:
     needs:
       - lint
       - ensure-pinned-actions
+      - static_checks
       - smoke
       - nox
       - adk-py
       - langchain-py
       - upload-wheel
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     timeout-minutes: 5
     if: always()
     steps:
@@ -138,12 +159,13 @@ jobs:
           }
 
           check_result "lint" "${{ needs.lint.result }}"
-          check_result "ensure-pinned-actions" "${{ needs.ensure-pinned-actions.result }}"
+          check_result "ensure-pinned-actions" "${{ needs['ensure-pinned-actions'].result }}"
+          check_result "static_checks" "${{ needs.static_checks.result }}"
           check_result "smoke" "${{ needs.smoke.result }}"
           check_result "nox" "${{ needs.nox.result }}"
-          check_result "adk-py" "${{ needs.adk-py.result }}"
-          check_result "langchain-py" "${{ needs.langchain-py.result }}"
-          check_result "upload-wheel" "${{ needs.upload-wheel.result }}"
+          check_result "adk-py" "${{ needs['adk-py'].result }}"
+          check_result "langchain-py" "${{ needs['langchain-py'].result }}"
+          check_result "upload-wheel" "${{ needs['upload-wheel'].result }}"
 
           if [ "$FAILED" -ne 0 ]; then
             echo "One or more required checks failed"
diff --git a/.github/workflows/langchain-py-test.yaml b/.github/workflows/langchain-py-test.yaml
index c49495f6..e53f1342 100644
--- a/.github/workflows/langchain-py-test.yaml
+++ b/.github/workflows/langchain-py-test.yaml
@@ -5,7 +5,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     timeout-minutes: 15
 
     steps:
diff --git a/AGENTS.md b/AGENTS.md
index 6da9e3a1..ca3b2a72 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -15,7 +15,8 @@ Use this file as the default playbook for work in this repository.
 2. **Use `mise` as the source of truth for tools and environment.**
 
 3. **Do not guess test commands or version coverage.**
-   - `py/noxfile.py` is the source of truth for nox session names, provider/version matrices, and CI coverage.
+   - `py/noxfile.py` is the source of truth for nox session names, provider/version matrices, and local reproduction commands.
+   - `.github/workflows/checks.yaml` is the source of truth for which sessions run in CI, on which Python versions, and outside vs. inside the nox shard matrix.
    - For provider and integration work, also check `py/src/braintrust/integrations/versioning.py`.
 
 4. **Keep changes narrow and validate with the smallest relevant test first.**
@@ -116,7 +117,7 @@ Do not guess:
 - supported provider versions
 - which tests a provider session runs
 
-Check `py/noxfile.py` and reproduce with the exact local session CI uses.
+Check `py/noxfile.py` and `.github/workflows/checks.yaml`, then reproduce with the exact local session CI uses.
 
 ### Run the smallest relevant test first
 
@@ -143,6 +144,8 @@ Before changing provider/integration behavior:
 
 - `test_core` runs without optional vendor packages.
 - `test_types` runs pyright, mypy, and pytest on `py/src/braintrust/type_tests/`.
+- CI runs `pylint` and `test_types` via the dedicated `static_checks` workflow job on Ubuntu across the configured Python matrix, not inside the sharded `nox` job.
+- The sharded `nox` workflow excludes `pylint` and `test_types`; use `py/scripts/nox-matrix.py --exclude-session ...` when reproducing shard membership locally.
 - wrapper coverage is split across dedicated nox sessions by provider/version.
 - `test-wheel` is a wheel sanity check and requires a built wheel first.
 
diff --git a/py/scripts/nox-matrix.py b/py/scripts/nox-matrix.py
index 4c9ff0c3..11460abf 100644
--- a/py/scripts/nox-matrix.py
+++ b/py/scripts/nox-matrix.py
@@ -6,7 +6,7 @@
 by weight descending and greedily assigns each to the lightest shard.
 
 Usage:
-    python nox-matrix.py <shard_index> <number_of_shards> [--dry-run]
+    python nox-matrix.py <shard_index> <number_of_shards> [--dry-run] [--exclude-session <name> ...]
 """
 
 import argparse
@@ -80,6 +80,12 @@ def main() -> None:
     parser.add_argument("shard_index", type=int, help="Zero-based shard index")
     parser.add_argument("num_shards", type=int, help="Total number of shards")
     parser.add_argument("--dry-run", action="store_true", help="Print assignment without running nox")
+    parser.add_argument(
+        "--exclude-session",
+        action="append",
+        default=[],
+        help="Exclude a nox session from shard assignment. May be passed multiple times.",
+    )
     parser.add_argument(
         "--output-durations",
         type=Path,
@@ -108,6 +114,8 @@ def main() -> None:
     weights_file = root_dir / "py" / "scripts" / "session-weights.json"
 
     all_sessions = get_nox_sessions(noxfile)
+    excluded_sessions = set(args.exclude_session)
+    all_sessions = [session for session in all_sessions if session not in excluded_sessions]
     weights, default_weight = load_weights(weights_file)
     shard_assignments = assign_shards(all_sessions, args.num_shards, weights, default_weight)