diff --git a/.github/TESTING.md b/.github/TESTING.md
new file mode 100644
index 00000000..a7e5b4f9
--- /dev/null
+++ b/.github/TESTING.md
@@ -0,0 +1,41 @@
+# Pull request test commands
+
+The automatic PR workflow (`test_code.yml`) contains only **Lint & Format**.
+Model, tokenizer, image-processor, and processor jobs live in a separate workflow
+(`model_tests.yml`) that does not subscribe to pull request events. They do not
+appear as queued or skipped PR checks before a command is posted.
+
+Those tests run on a pull request only when **IMvision12** posts a new
+conversation comment containing exactly:
+
+```text
+/run-tests
+```
+
+Other users' commands, issue comments, edited comments, and other text do not
+authorize the test suite. Re-running a comment-triggered test job also requires
+IMvision12 to be the triggering account.
+
+The command starts the existing 16 test jobs: 9 model shards (Torch, TensorFlow,
+and JAX), 1 tokenizer job, 3 image-processor jobs, and 3 processor jobs. They test
+the open PR's head commit captured when the request is authorized. A later push
+does not start another test run; post `/run-tests` again to test the new commit.
+
+Results appear on the tested PR commit as **Requested model, tokenizer & processor
+tests**, with a link to the workflow's individual jobs. If these tests must block
+merging, require this aggregate check in the repository's branch protection or
+ruleset. The test check is created only after an authorized command.
+
+The updated workflow must be present on the repository's default branch before
+GitHub delivers comment-triggered runs. No additional personal access token or
+repository secret is needed.
+
+Release events start the same lint and test jobs automatically in
+`model_tests.yml`, with the existing commands and matrices unchanged. The release,
+documentation, and standalone cross-backend parity workflow files are unchanged.
+
+Authorization and result-reporting jobs have check-writing permission but never
+check out PR code. Test jobs have read-only repository access and do not persist
+checkout credentials. Comment-triggered tests do not use shared Actions caches
+or publish Codecov coverage from the default-branch event context; release runs
+retain their existing cache and coverage steps.
diff --git a/.github/workflows/model_tests.yml b/.github/workflows/model_tests.yml
new file mode 100644
index 00000000..38ae3748
--- /dev/null
+++ b/.github/workflows/model_tests.yml
@@ -0,0 +1,327 @@
+name: Model tests
+on:
+  release:
+    types: [created]
+  issue_comment:
+    types: [created]
+
+jobs:
+  lint-and-format:
+    name: Lint & Format
+    if: github.event_name == 'release'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - run: pip install ruff==0.16.1
+      - run: ruff check .
+      - run: ruff format --check .
+
+  authorize-tests:
+    name: Authorize PR tests
+    if: >-
+      github.event_name == 'issue_comment' &&
+      github.event.issue.pull_request &&
+      github.event.comment.user.login == 'IMvision12' &&
+      github.triggering_actor == 'IMvision12' &&
+      github.event.comment.body == '/run-tests'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+      checks: write
+    outputs:
+      run_tests: ${{ steps.authorize.outputs.run_tests }}
+      head_sha: ${{ steps.authorize.outputs.head_sha }}
+      check_run_id: ${{ steps.authorize.outputs.check_run_id }}
+    steps:
+      # This privileged job never checks out or executes PR-controlled files.
+      - name: Validate owner command and pin the PR commit
+        id: authorize
+        uses: actions/github-script@v9
+        with:
+          script: |
+            const { issue, comment, action } = context.payload;
+            if (action !== 'created' || !issue?.pull_request ||
+                comment?.user?.login?.toLowerCase() !== 'imvision12' ||
+                comment.body !== '/run-tests') {
+              throw new Error('Only IMvision12 can request PR tests with /run-tests.');
+            }
+            const { data: pr } = await github.rest.pulls.get({
+              ...context.repo,
+              pull_number: issue.number,
+            });
+            if (pr.state !== 'open') {
+              throw new Error('Tests can only be requested on an open pull request.');
+            }
+            if (!/^[0-9a-f]{40}$/.test(pr.head.sha)) {
+              throw new Error('GitHub returned an invalid PR head commit.');
+            }
+            const { data: check } = await github.rest.checks.create({
+              ...context.repo,
+              name: 'Requested model, tokenizer & processor tests',
+              head_sha: pr.head.sha,
+              status: 'in_progress',
+              details_url: `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`,
+              output: {
+                title: 'PR tests requested by IMvision12',
+                summary: `Testing PR #${issue.number} at ${pr.head.sha}. New pushes require a new /run-tests comment.`,
+              },
+            });
+            core.setOutput('head_sha', pr.head.sha);
+            core.setOutput('check_run_id', String(check.id));
+            core.setOutput('run_tests', 'true');
+
+  test-code:
+    name: Test the code (${{ matrix.backend }} ${{ matrix.shard }})
+    needs: [lint-and-format, authorize-tests]
+    if: >-
+      always() && !cancelled() &&
+      ((github.event_name == 'release' && needs.lint-and-format.result == 'success') ||
+       (github.event_name == 'issue_comment' && github.triggering_actor == 'IMvision12' &&
+        needs.authorize-tests.outputs.run_tests == 'true'))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    strategy:
+      fail-fast: false
+      # Shard the model suite BY MODEL across parallel jobs (see the --shard
+      # option in tests/conftest.py). torch is fast enough unsharded; the JAX and
+      # TF legs trace + XLA-compile every model, so they are split to stay under
+      # the per-job time cap. Stacks with the per-model build-once reuse.
+      matrix:
+        include:
+          - { backend: torch, shard: "1/2" }
+          - { backend: torch, shard: "2/2" }
+          - { backend: tensorflow, shard: "1/3" }
+          - { backend: tensorflow, shard: "2/3" }
+          - { backend: tensorflow, shard: "3/3" }
+          - { backend: jax, shard: "1/4" }
+          - { backend: jax, shard: "2/4" }
+          - { backend: jax, shard: "3/4" }
+          - { backend: jax, shard: "4/4" }
+    env:
+      KERAS_BACKEND: ${{ matrix.backend }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.authorize-tests.outputs.head_sha }}
+          persist-credentials: ${{ github.event_name != 'issue_comment' }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - name: Cache pip packages
+        if: github.event_name != 'issue_comment'
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: pip-${{ matrix.backend }}-${{ hashFiles('pyproject.toml') }}
+          restore-keys: pip-${{ matrix.backend }}-
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools
+          pip install -U "keras>=3.15.0" pytest pytest-cov
+          # CPU-only torch wheel: the default PyPI wheel bundles
+          # CUDA/Triton which segfaults during `import triton.knobs`
+          # on CUDA-less Linux runners (gets pulled in transitively by
+          # torchvision -> torch._dynamo).
+          pip install --index-url https://download.pytorch.org/whl/cpu \
+              "torch>=2.5.0" torchvision
+          pip install "jax[cpu]" "tensorflow-cpu>=2.19.0"
+          pip install sentencepiece "matplotlib>=3.8.0" pillow
+          pip install huggingface_hub safetensors
+          pip install "transformers>=5.0.0"
+          pip install .
+      - name: Run all tests
+        run: |
+          pytest tests/integration/test_backend_compatibility.py \
+                 tests/integration/test_serialization.py \
+                 tests/integration/test_model_saving.py \
+                 tests/integration/test_data_formats.py \
+                 tests/integration/test_auto_registry.py \
+                 --shard ${{ matrix.shard }} \
+                 -v --durations=20 --cov=zeromodels --cov-append \
+                 -m "not slow and not gpu"
+      - name: Generate coverage
+        run: coverage xml -o coverage.xml
+      - name: Upload coverage
+        if: github.event_name != 'issue_comment'
+        uses: codecov/codecov-action@v5
+        with:
+          files: coverage.xml
+          flags: ${{ matrix.backend }}
+          fail_ci_if_error: false
+
+  test-tokenizers:
+    name: Test tokenizers (vs HF)
+    needs: [lint-and-format, authorize-tests]
+    if: >-
+      always() && !cancelled() &&
+      ((github.event_name == 'release' && needs.lint-and-format.result == 'success') ||
+       (github.event_name == 'issue_comment' && github.triggering_actor == 'IMvision12' &&
+        needs.authorize-tests.outputs.run_tests == 'true'))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    env:
+      KERAS_BACKEND: torch
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.authorize-tests.outputs.head_sha }}
+          persist-credentials: ${{ github.event_name != 'issue_comment' }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - name: Cache pip packages
+        if: github.event_name != 'issue_comment'
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: pip-tokenizers-${{ hashFiles('pyproject.toml') }}
+          restore-keys: pip-tokenizers-
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools
+          pip install -U "keras>=3.15.0" pytest
+          pip install --index-url https://download.pytorch.org/whl/cpu "torch>=2.5.0"
+          pip install sentencepiece huggingface_hub "matplotlib>=3.8.0" pillow
+          pip install "transformers>=5.0.0"
+          pip install .
+      - name: Run tokenizer parity tests
+        run: |
+          pytest tests/processors/test_keras_tokenizers_vs_hf.py \
+                 -v --durations=20
+
+  test-image-processors:
+    name: Test image processors (vs HF, ${{ matrix.backend }})
+    needs: [lint-and-format, authorize-tests]
+    if: >-
+      always() && !cancelled() &&
+      ((github.event_name == 'release' && needs.lint-and-format.result == 'success') ||
+       (github.event_name == 'issue_comment' && github.triggering_actor == 'IMvision12' &&
+        needs.authorize-tests.outputs.run_tests == 'true'))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    strategy:
+      fail-fast: false
+      matrix:
+        backend: [torch, tensorflow, jax]
+    env:
+      KERAS_BACKEND: ${{ matrix.backend }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.authorize-tests.outputs.head_sha }}
+          persist-credentials: ${{ github.event_name != 'issue_comment' }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - name: Cache pip packages
+        if: github.event_name != 'issue_comment'
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: pip-${{ matrix.backend }}-${{ hashFiles('pyproject.toml') }}
+          restore-keys: pip-${{ matrix.backend }}-
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools
+          pip install -U "keras>=3.15.0" pytest
+          pip install --index-url https://download.pytorch.org/whl/cpu \
+              "torch>=2.5.0" torchvision
+          pip install "jax[cpu]" "tensorflow-cpu>=2.19.0"
+          pip install sentencepiece "matplotlib>=3.8.0" pillow
+          pip install huggingface_hub safetensors
+          pip install "transformers>=5.0.0"
+          pip install .
+      - name: Run image processor parity tests
+        run: |
+          pytest tests/processors/test_keras_image_processors_vs_hf.py \
+                 -v --durations=20
+
+  test-processors:
+    name: Test processors (vs HF, ${{ matrix.backend }})
+    needs: [lint-and-format, authorize-tests]
+    if: >-
+      always() && !cancelled() &&
+      ((github.event_name == 'release' && needs.lint-and-format.result == 'success') ||
+       (github.event_name == 'issue_comment' && github.triggering_actor == 'IMvision12' &&
+        needs.authorize-tests.outputs.run_tests == 'true'))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    strategy:
+      fail-fast: false
+      matrix:
+        backend: [torch, tensorflow, jax]
+    env:
+      KERAS_BACKEND: ${{ matrix.backend }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.authorize-tests.outputs.head_sha }}
+          persist-credentials: ${{ github.event_name != 'issue_comment' }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - name: Cache pip packages
+        if: github.event_name != 'issue_comment'
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: pip-${{ matrix.backend }}-${{ hashFiles('pyproject.toml') }}
+          restore-keys: pip-${{ matrix.backend }}-
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools
+          pip install -U "keras>=3.15.0" pytest
+          pip install --index-url https://download.pytorch.org/whl/cpu \
+              "torch>=2.5.0" torchvision
+          pip install "jax[cpu]" "tensorflow-cpu>=2.19.0"
+          pip install sentencepiece "matplotlib>=3.8.0" pillow
+          pip install huggingface_hub safetensors
+          pip install "transformers>=5.0.0"
+          pip install .
+      - name: Run processor parity tests
+        run: |
+          pytest tests/processors/test_keras_processors_vs_hf.py \
+                 -v --durations=20
+
+  report-pr-tests:
+    name: Report requested PR tests
+    needs: [authorize-tests, test-code, test-tokenizers, test-image-processors, test-processors]
+    if: >-
+      always() && github.event_name == 'issue_comment' &&
+      needs.authorize-tests.outputs.run_tests == 'true'
+    runs-on: ubuntu-latest
+    permissions:
+      checks: write
+    steps:
+      # Keep the write token isolated from the jobs that execute PR code.
+      - name: Publish the result on the tested PR commit
+        uses: actions/github-script@v9
+        env:
+          TEST_RESULTS: ${{ toJSON(needs) }}
+          CHECK_RUN_ID: ${{ needs.authorize-tests.outputs.check_run_id }}
+        with:
+          script: |
+            const needs = JSON.parse(process.env.TEST_RESULTS);
+            const groups = ['test-code', 'test-tokenizers', 'test-image-processors', 'test-processors'];
+            const results = groups.map(name => needs[name].result);
+            const conclusion = results.every(result => result === 'success')
+              ? 'success'
+              : results.includes('cancelled') ? 'cancelled' : 'failure';
+            await github.rest.checks.update({
+              ...context.repo,
+              check_run_id: Number(process.env.CHECK_RUN_ID),
+              status: 'completed',
+              conclusion,
+              output: {
+                title: `Requested PR tests: ${conclusion}`,
+                summary: groups.map(name => `- ${name}: ${needs[name].result}`).join('\n'),
+              },
+            });
diff --git a/.github/workflows/test_code.yml b/.github/workflows/test_code.yml
index 405b5b11..865ea8b6 100644
--- a/.github/workflows/test_code.yml
+++ b/.github/workflows/test_code.yml
@@ -1,8 +1,6 @@
 name: Tests
 on:
   pull_request:
-  release:
-    types: [created]
 
 jobs:
   lint-and-format:
@@ -16,175 +14,3 @@ jobs:
       - run: pip install ruff==0.16.1
       - run: ruff check .
       - run: ruff format --check .
-
-  test-code:
-    name: Test the code (${{ matrix.backend }} ${{ matrix.shard }})
-    needs: lint-and-format
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      # Shard the model suite BY MODEL across parallel jobs (see the --shard
-      # option in tests/conftest.py). torch is fast enough unsharded; the JAX and
-      # TF legs trace + XLA-compile every model, so they are split to stay under
-      # the per-job time cap. Stacks with the per-model build-once reuse.
-      matrix:
-        include:
-          - { backend: torch, shard: "1/2" }
-          - { backend: torch, shard: "2/2" }
-          - { backend: tensorflow, shard: "1/3" }
-          - { backend: tensorflow, shard: "2/3" }
-          - { backend: tensorflow, shard: "3/3" }
-          - { backend: jax, shard: "1/4" }
-          - { backend: jax, shard: "2/4" }
-          - { backend: jax, shard: "3/4" }
-          - { backend: jax, shard: "4/4" }
-    env:
-      KERAS_BACKEND: ${{ matrix.backend }}
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.11'
-      - name: Cache pip packages
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ matrix.backend }}-${{ hashFiles('pyproject.toml') }}
-          restore-keys: pip-${{ matrix.backend }}-
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip setuptools
-          pip install -U "keras>=3.15.0" pytest pytest-cov
-          # CPU-only torch wheel: the default PyPI wheel bundles
-          # CUDA/Triton which segfaults during `import triton.knobs`
-          # on CUDA-less Linux runners (gets pulled in transitively by
-          # torchvision -> torch._dynamo).
-          pip install --index-url https://download.pytorch.org/whl/cpu \
-              "torch>=2.5.0" torchvision
-          pip install "jax[cpu]" "tensorflow-cpu>=2.19.0"
-          pip install sentencepiece "matplotlib>=3.8.0" pillow
-          pip install huggingface_hub safetensors
-          pip install "transformers>=5.0.0"
-          pip install .
-      - name: Run all tests
-        run: |
-          pytest tests/integration/test_backend_compatibility.py \
-                 tests/integration/test_serialization.py \
-                 tests/integration/test_model_saving.py \
-                 tests/integration/test_data_formats.py \
-                 tests/integration/test_auto_registry.py \
-                 --shard ${{ matrix.shard }} \
-                 -v --durations=20 --cov=zeromodels --cov-append \
-                 -m "not slow and not gpu"
-      - name: Generate coverage
-        run: coverage xml -o coverage.xml
-      - name: Upload coverage
-        uses: codecov/codecov-action@v5
-        with:
-          files: coverage.xml
-          flags: ${{ matrix.backend }}
-          fail_ci_if_error: false
-
-  test-tokenizers:
-    name: Test tokenizers (vs HF)
-    needs: lint-and-format
-    runs-on: ubuntu-latest
-    env:
-      KERAS_BACKEND: torch
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.11'
-      - name: Cache pip packages
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-tokenizers-${{ hashFiles('pyproject.toml') }}
-          restore-keys: pip-tokenizers-
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip setuptools
-          pip install -U "keras>=3.15.0" pytest
-          pip install --index-url https://download.pytorch.org/whl/cpu "torch>=2.5.0"
-          pip install sentencepiece huggingface_hub "matplotlib>=3.8.0" pillow
-          pip install "transformers>=5.0.0"
-          pip install .
-      - name: Run tokenizer parity tests
-        run: |
-          pytest tests/processors/test_keras_tokenizers_vs_hf.py \
-                 -v --durations=20
-
-  test-image-processors:
-    name: Test image processors (vs HF, ${{ matrix.backend }})
-    needs: lint-and-format
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        backend: [torch, tensorflow, jax]
-    env:
-      KERAS_BACKEND: ${{ matrix.backend }}
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.11'
-      - name: Cache pip packages
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ matrix.backend }}-${{ hashFiles('pyproject.toml') }}
-          restore-keys: pip-${{ matrix.backend }}-
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip setuptools
-          pip install -U "keras>=3.15.0" pytest
-          pip install --index-url https://download.pytorch.org/whl/cpu \
-              "torch>=2.5.0" torchvision
-          pip install "jax[cpu]" "tensorflow-cpu>=2.19.0"
-          pip install sentencepiece "matplotlib>=3.8.0" pillow
-          pip install huggingface_hub safetensors
-          pip install "transformers>=5.0.0"
-          pip install .
-      - name: Run image processor parity tests
-        run: |
-          pytest tests/processors/test_keras_image_processors_vs_hf.py \
-                 -v --durations=20
-
-  test-processors:
-    name: Test processors (vs HF, ${{ matrix.backend }})
-    needs: lint-and-format
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        backend: [torch, tensorflow, jax]
-    env:
-      KERAS_BACKEND: ${{ matrix.backend }}
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.11'
-      - name: Cache pip packages
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ matrix.backend }}-${{ hashFiles('pyproject.toml') }}
-          restore-keys: pip-${{ matrix.backend }}-
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip setuptools
-          pip install -U "keras>=3.15.0" pytest
-          pip install --index-url https://download.pytorch.org/whl/cpu \
-              "torch>=2.5.0" torchvision
-          pip install "jax[cpu]" "tensorflow-cpu>=2.19.0"
-          pip install sentencepiece "matplotlib>=3.8.0" pillow
-          pip install huggingface_hub safetensors
-          pip install "transformers>=5.0.0"
-          pip install .
-      - name: Run processor parity tests
-        run: |
-          pytest tests/processors/test_keras_processors_vs_hf.py \
-                 -v --durations=20