@@ -106,15 +106,21 @@ jobs:
           echo "Smoke matrix: $json"
 
   smoke:
-    name: Blender ${{ matrix.series }} smoke
+    # The catalog (a cold Blender launch per happy path and per falsifier) is
+    # split across three parallel jobs per series (#529): one serial job
+    # took 15-40 minutes and grew two launches per series with every example.
+    # Shard 0 also runs the template, harness-driver and canary steps, which
+    # are not catalog rows.
+    name: Blender ${{ matrix.series }} smoke (${{ matrix.shard }}/3)
     needs: resolve-matrix
     if: needs.resolve-matrix.result == 'success'
     runs-on: ubuntu-latest
-    timeout-minutes: 75  # happy paths + one falsifier per catalog row (~2x the old run)
+    timeout-minutes: 45
     strategy:
       fail-fast: false
       matrix:
         series: ${{ fromJSON(needs.resolve-matrix.outputs.series) }}
+        shard: [0, 1, 2]  # keep in step with the K/3 below
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
 
@@ -203,17 +209,20 @@ jobs:
             || { echo "::error::version does not match series ${{ matrix.series }}"; exit 1; }
 
       - name: Run in-Blender smoke driver
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           mkdir -p "$RUNNER_TEMP/out"
           xvfb-run -a "$BLENDER" --background --python-exit-code 1 --python tests/smoke/run_smoke.py -- "$RUNNER_TEMP/out"
 
       - name: Build template input scene
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           xvfb-run -a "$BLENDER" --background --python-exit-code 1 --python tests/smoke/make_input.py -- "$RUNNER_TEMP/out/input.blend"
 
       - name: Headless glTF template runs (exit 0, .glb produced)
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           xvfb-run -a "$BLENDER" --background "$RUNNER_TEMP/out/input.blend" \
@@ -223,6 +232,7 @@ jobs:
           head -c4 "$RUNNER_TEMP/out/out.glb" | grep -q "glTF" || { echo "::error::not a glTF binary"; exit 1; }
 
       - name: Headless template no-mesh path returns exit 5
+        if: matrix.shard == 0
         run: |
           set +e
           xvfb-run -a "$BLENDER" --background "$RUNNER_TEMP/out/empty.blend" \
@@ -233,6 +243,7 @@ jobs:
           echo "no-mesh exit code = $code (correct)"
 
       - name: Headless template applies the new modifier after the existing stack (#468)
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           # stack.blend: a cube with a live SUBSURF (levels 1). SUBSURF then
@@ -245,18 +256,21 @@ jobs:
             "$RUNNER_TEMP/out/stack.glb" 48
 
       - name: Extension template passes Blender's own manifest validator
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           "$BLENDER" --command extension validate templates/extension-addon-template
 
       - name: Build pipeline template fixture GLB
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           xvfb-run -a "$BLENDER" --background --python-exit-code 1 --python tests/smoke/make_pipeline_glb.py -- \
             "$RUNNER_TEMP/out/pipeline_src.glb"
           test -s "$RUNNER_TEMP/out/pipeline_src.glb" || { echo "::error::pipeline fixture missing"; exit 1; }
 
       - name: Headless AI asset pipeline template runs (exit 0, LODs produced)
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           mkdir -p "$RUNNER_TEMP/out/pipeline"
@@ -271,6 +285,7 @@ jobs:
           head -c4 "$RUNNER_TEMP/out/pipeline/lod0.glb" | grep -q "glTF" || { echo "::error::lod0 not a glTF binary"; exit 1; }
 
       - name: Headless pipeline template missing input returns exit 13
+        if: matrix.shard == 0
         run: |
           set +e
           xvfb-run -a "$BLENDER" --background --python-exit-code 1 --python templates/ai-asset-pipeline-template/pipeline.py -- \
@@ -283,6 +298,7 @@ jobs:
           echo "missing-input exit code = $code (correct)"
 
       - name: Pipeline template keeps every part of a shared-mesh, parented GLB (#462, #467)
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           # Root rotated 90 deg on X, scaled 2x, at z=3; Body plus two wheels
@@ -301,6 +317,7 @@ jobs:
             "$RUNNER_TEMP/out/parented_src.glb" "$RUNNER_TEMP/out/pipeline_parented/lod0.glb"
 
       - name: Falsifier - pipeline template rejects a 2 km asset with exit 8
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           xvfb-run -a "$BLENDER" --background --python-exit-code 1 --python tests/smoke/make_pipeline_glb.py -- \
@@ -316,6 +333,7 @@ jobs:
           echo "out-of-range extent exit code = $code (correct)"
 
       - name: Headless render template runs (exit 0, PNG produced)
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           # Cycles (CPU) so this is reliable on GPU-less runners; the EEVEE-id regression
@@ -329,6 +347,7 @@ jobs:
       # file would make summarize.py's "zero PASS is red" guard unreachable
       # (#536). Each one asserts its own verdict inline instead.
       - name: Canary - expected skip is SKIP not PASS
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           python3 tests/smoke/run_example.py --no-record \
@@ -342,6 +361,7 @@ jobs:
             || { echo "::error::expected skip was not classified SKIP"; exit 1; }
 
       - name: Canary - unexpected skip is red
+        if: matrix.shard == 0
         run: |
           set +e
           python3 tests/smoke/run_example.py --no-record \
@@ -357,6 +377,7 @@ jobs:
           echo "unexpected skip exited 1 (correct)"
 
       - name: Canary - uncaught exception is red
+        if: matrix.shard == 0
         run: |
           set +e
           python3 tests/smoke/run_example.py --no-record \
@@ -371,6 +392,7 @@ jobs:
           echo "uncaught exception exited 1 (correct)"
 
       - name: Canary - post-exit sidecar
+        if: matrix.shard == 0
         run: |
           set -euo pipefail
           python3 tests/smoke/run_example.py --no-record \
@@ -385,6 +407,7 @@ jobs:
             || { echo "::error::post-exit sidecar canary did not PASS"; exit 1; }
 
       - name: Canary - missing sidecar is red
+        if: matrix.shard == 0
         run: |
           set +e
           python3 tests/smoke/run_example.py --no-record \
@@ -407,6 +430,7 @@ jobs:
           python3 tests/smoke/run_catalog.py \
             --blender "$BLENDER" \
             --series "${{ matrix.series }}" \
+            --shard "${{ matrix.shard }}/3" \
             --status "$BDT_SMOKE_STATUS" \
             --out "$RUNNER_TEMP/out" \
             --xvfb \
 
@@ -292,8 +292,8 @@ Should the repository move to an organization, or `release.yml` stop pushing
 to `main`, these are the checks that run unconditionally on every PR and are
 therefore the required-check set:
 
-- `Blender 4.5 smoke`
-- `Blender 5.2 smoke`
+- `Blender 4.5 smoke (0/3)`, `(1/3)`, `(2/3)` (the catalog is sharded three ways, #529)
+- `Blender 5.2 smoke (0/3)`, `(1/3)`, `(2/3)`
 - `Ecosystem drift check`
 - `Validate content counts`
 - `Validate plugin manifest`
@@ -302,14 +302,14 @@ therefore the required-check set:
 
 Three checks that appear on PRs are deliberately **excluded**:
 
-- **`Blender 5.1 smoke` is label-gated.** It only runs when `needs-5.1` is
+- **`Blender 5.1 smoke (K/3)` is label-gated.** It only runs when `needs-5.1` is
   applied. As a required check it would block every unlabeled PR forever on
   a job that never reports.
 - **`Auto-label by path`** — `label-sync.yml` triggers on `opened` and
   `synchronize` only. A reopened PR with no new push never reports it.
 - **`Resolve smoke matrix`** — skipped on label events other than
   `needs-5.1`, and it is plumbing rather than a gate; its failure already
-  blocks the two smoke jobs that depend on it.
+  blocks the smoke jobs that depend on it.
 
 The two `Socket Security` checks come from a third-party GitHub App. An
 outage or an uninstall would deadlock merges, so they are advisory.
 
@@ -54,7 +54,7 @@
 
 ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, os.path.join(ROOT, "tests", "smoke"))
-from protocol import FORBIDDEN_FALSIFIER_EXITS  # noqa: E402
+from protocol import FORBIDDEN_FALSIFIER_EXITS, in_shard, parse_shard  # noqa: E402,F401
 
 SHOWCASE = os.path.join(ROOT, "showcase")
 
@@ -236,21 +236,6 @@ def check_static():
 RUN_TIMEOUT = 900  # seconds per Blender run, matching tests/smoke/run_example.py
 
 
-def parse_shard(text):
-    """'K/N' -> (K, N) with 0 <= K < N; argparse-friendly."""
-    try:
-        k, n = (int(x) for x in text.split("/"))
-    except ValueError:
-        raise argparse.ArgumentTypeError(f"--shard wants K/N, got {text!r}")
-    if n < 1 or not 0 <= k < n:
-        raise argparse.ArgumentTypeError(f"--shard {text!r}: need 0 <= K < N")
-    return k, n
-
-
-def in_shard(index, shard):
-    return shard is None or index % shard[1] == shard[0]
-
-
 def check_runtime(blender, only=None, shard=None):
     failures, checked = [], 0
     for index, (name, readme, script) in enumerate(piece_paths()):
 
@@ -10,6 +10,7 @@
 """
 from __future__ import annotations
 
+import argparse
 import os
 from typing import Optional, Tuple
 
@@ -215,3 +216,20 @@ def classify_content_falsifier(phase, error_type):
     if error_type in BROKEN_CODE_ERRORS:
         return FAIL, f"check raised {error_type}: the edit broke the code, not the contract"
     return FALSIFIED, ""
+
+
+# Sharding: run_catalog.py (PR smoke, #529) and check_falsifier_targets.py (the
+# weekly showcase sweep, #482) split their rows across parallel jobs the same way.
+def parse_shard(text):
+    """'K/N' -> (K, N) with 0 <= K < N; argparse-friendly."""
+    try:
+        k, n = (int(x) for x in text.split("/"))
+    except ValueError:
+        raise argparse.ArgumentTypeError(f"--shard wants K/N, got {text!r}")
+    if n < 1 or not 0 <= k < n:
+        raise argparse.ArgumentTypeError(f"--shard {text!r}: need 0 <= K < N")
+    return k, n
+
+
+def in_shard(index, shard):
+    return shard is None or index % shard[1] == shard[0]
@@ -13,6 +13,9 @@
 A row may set ``timeout`` (seconds) for an example that legitimately needs
 longer than run_example.py's default; a hung run is killed and reported as a
 failure, and the catalog moves on to the next row.
+
+``--shard K/N`` runs only rows whose catalog index is K mod N, so CI can split
+the catalog across parallel jobs (#529); the shards partition every row.
 """
 from __future__ import annotations
 
@@ -24,10 +27,15 @@
 
 HERE = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, HERE)
-from protocol import parse_version  # noqa: E402
+from protocol import in_shard, parse_shard, parse_version  # noqa: E402
 from run_example import append_status  # noqa: E402
 
 
+def select_rows(catalog, shard):
+    """The rows this shard runs; every row lands in exactly one shard."""
+    return [row for i, row in enumerate(catalog) if in_shard(i, shard)]
+
+
 def main(argv=None):
     p = argparse.ArgumentParser()
     p.add_argument("--blender", required=True)
@@ -39,13 +47,20 @@ def main(argv=None):
     p.add_argument("--fail-fast", action="store_true", help="stop at the first failure")
     p.add_argument("--no-falsifiers", action="store_true",
                    help="run only the happy paths (local iteration; CI runs falsifiers)")
+    p.add_argument("--shard", type=parse_shard, default=None, metavar="K/N",
+                   help="run only rows with index %% N == K (parallel CI jobs)")
     args = p.parse_args(argv)
 
     with open(args.catalog, encoding="utf-8") as fh:
         catalog = json.load(fh)
     if not catalog:
         print("ERROR: catalog is empty; nothing would be smoke-tested", file=sys.stderr)
         return 1
+    total = len(catalog)
+    catalog = select_rows(catalog, args.shard)
+    if not catalog:
+        print(f"ERROR: shard {args.shard} selects no row of {total}", file=sys.stderr)
+        return 1
 
     os.makedirs(args.out, exist_ok=True)
     runner = os.path.join(HERE, "run_example.py")
@@ -133,7 +148,8 @@ def row_cmd(item, run_name, extra, falsifier=None):
                     break
         if failures and args.fail_fast:
             break
-    print(f"catalog finished {n} of {len(catalog)} entries, {n_falsifiers} falsifier run(s)",
+    shard = f" (shard {args.shard[0]}/{args.shard[1]} of {total} rows)" if args.shard else ""
+    print(f"catalog finished {n} of {len(catalog)} entries{shard}, {n_falsifiers} falsifier run(s)",
           flush=True)
     if failures:
         print(f"{len(failures)} catalog failure(s):", file=sys.stderr)
 
@@ -346,6 +346,23 @@ def test_two_broken_examples_are_both_reported(self):
         self.assertIn("b (exit 1)", err)
         self.assertIn("d (exit 3)", err)
 
+    def test_shards_partition_the_catalog(self):
+        # #529: CI splits the catalog across jobs; every row runs exactly once
+        rows = [{"name": n, "script": f"{n}.py"} for n in "abcdefg"]
+        seen_all = []
+        for k in range(3):
+            code, seen, _ = self._run(rows, {}, ("--shard", f"{k}/3", "--no-falsifiers"))
+            self.assertEqual(code, 0)
+            seen_all += seen
+        self.assertEqual(sorted(seen_all), list("abcdefg"))
+
+    def test_empty_shard_is_red(self):
+        rows = [{"name": "a", "script": "a.py"}]
+        code, seen, err = self._run(rows, {}, ("--shard", "1/2"))
+        self.assertEqual(code, 1)
+        self.assertEqual(seen, [])
+        self.assertIn("selects no row", err)
+
     def test_fail_fast_is_opt_in(self):
         rows = [{"name": n, "script": f"{n}.py"} for n in ("a", "b", "c")]
         code, seen, _ = self._run(rows, {"a": 1}, extra=("--fail-fast",))