djm81 · Oct 16, 2026 · Oct 16, 2026 · Oct 16, 2026
diff --git a/.github/workflows/downstream-semgrep.yml b/.github/workflows/downstream-semgrep.yml
@@ -0,0 +1,142 @@
+name: Downstream Semgrep candidate
+
+on:
+  pull_request:
+    paths:
+      - 'scripts/downstream_semgrep.py'
+      - 'scripts/verify_downstream_semgrep.py'
+      - 'ci/downstream*'
+      - 'tools/downstream_semgrep/**'
+      - '.github/workflows/downstream-semgrep.yml'
+      - 'tests/unit/scripts/test_downstream_semgrep.py'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  matrix:
+    runs-on: ubuntu-24.04
+    outputs:
+      cells: ${{ steps.matrix.outputs.cells }}
+    steps:
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
+        with:
+          python-version: '3.13'
+      - id: matrix
+        shell: bash
+        run: |
+          cells="$(python scripts/verify_downstream_semgrep.py matrix)"
+          echo "cells=$cells" >> "$GITHUB_OUTPUT"
+
+  candidate:
+    needs: matrix
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJSON(needs.matrix.outputs.cells) }}
+    runs-on: ${{ matrix.runner }}
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
+        with:
+          python-version: ${{ matrix.python_version }}
+      - uses: astral-sh/setup-uv@d0cc045d04ccac9d8b7881df0226f9e82c39688e
+        with:
+          enable-cache: false
+          version: '0.12.19'
+      - name: Execute native candidate cell
+        if: matrix.container_image == ''
+        shell: bash
+        env:
+          CELL_PLATFORM: ${{ matrix.platform }}
+          CELL_PYTHON: ${{ matrix.python_version }}
+        run: |
+          python scripts/verify_downstream_semgrep.py cell --platform "$CELL_PLATFORM" --python-version "$CELL_PYTHON" --output "$RUNNER_TEMP/downstream-cell"
+      - name: Execute native musl candidate cell
+        if: matrix.container_image != ''
+        shell: bash
+        env:
+          CELL_PLATFORM: ${{ matrix.platform }}
+          CELL_PYTHON: ${{ matrix.python_version }}
+          CELL_IMAGE: ${{ matrix.container_image }}
+        run: |
+          case "$CELL_IMAGE" in python:*@sha256:*) ;; *) echo 'Unpinned musl image' >&2; exit 1 ;; esac
+          mkdir -p "$RUNNER_TEMP/downstream-musl"
+          status=0
+          docker run --rm \
+            --mount "type=bind,src=$GITHUB_WORKSPACE,dst=/workspace,readonly" \
+            --mount "type=bind,src=$RUNNER_TEMP/downstream-musl,dst=/evidence" \
+            -e CELL_PLATFORM -e CELL_PYTHON \
+            -w /workspace "$CELL_IMAGE" sh -euc '
+              apk add --no-cache git build-base libffi-dev openssl-dev cargo
+              git config --global --add safe.directory /workspace
+              python scripts/verify_downstream_semgrep.py uv-requirements > /evidence/uv-bootstrap.txt
+              python -m pip install --require-hashes --only-binary=:all: --index-url https://pypi.org/simple -r /evidence/uv-bootstrap.txt
+              python scripts/verify_downstream_semgrep.py cell --platform "$CELL_PLATFORM" --python-version "$CELL_PYTHON" --output /evidence/downstream-cell
+            ' || status=$?
+          if test -d "$RUNNER_TEMP/downstream-musl/downstream-cell"; then
+            cp -R "$RUNNER_TEMP/downstream-musl/downstream-cell" "$RUNNER_TEMP/downstream-cell"
+          fi
+          exit "$status"
+      - name: Retain candidate evidence on success or failure
+        if: always()
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a
+        with:
+          name: downstream-${{ matrix.platform }}-${{ matrix.python_version }}
+          path: |
+            ${{ runner.temp }}/downstream-cell
+            !${{ runner.temp }}/downstream-cell/*-env/**
+            !${{ runner.temp }}/downstream-cell/build-two/**
+          if-no-files-found: error
+          retention-days: 14
+
+  aggregate:
+    permissions:
+      contents: read
+      actions: read
+    if: always()
+    needs: [matrix, candidate]
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
+        with:
+          python-version: '3.13'
+      - name: Download immutable job artifacts
+        env:
+          GH_TOKEN: ${{ github.token }}
+          GH_REPO: ${{ github.repository }}
+          RUN_ID: ${{ github.run_id }}
+        shell: bash
+        run: |
+          gh run download "$RUN_ID" --pattern 'downstream-*' --dir "$RUNNER_TEMP/downstream-reports"
+      - name: Require complete successful candidate matrix
+        env:
+          MATRIX_RESULT: ${{ needs.matrix.result }}
+          CANDIDATE_RESULT: ${{ needs.candidate.result }}
+        shell: bash
+        run: |
+          test "$MATRIX_RESULT" = success
+          test "$CANDIDATE_RESULT" = success
+          python scripts/verify_downstream_semgrep.py aggregate --reports "$RUNNER_TEMP/downstream-reports"
+
+  protected-producer:
+    if: github.event_name == 'workflow_dispatch' && github.ref == 'refs/heads/dev'
+    needs: aggregate
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: read
+    steps:
+      - name: Refuse production bootstrap until separately approved roots exist
+        shell: bash
+        run: |
+          echo 'Candidate evidence only. Production producer bootstrap is unconfigured; no signing, attestation or publication is permitted.' >&2
+          exit 1
diff --git a/ci/downstream-semgrep-admissions.json b/ci/downstream-semgrep-admissions.json
@@ -0,0 +1,4 @@
+{
+  "schema_version": 1,
+  "admissions": []
+}
diff --git a/ci/downstream-semgrep-recipe.json b/ci/downstream-semgrep-recipe.json
@@ -0,0 +1,105 @@
+{
+  "schema_version": 1,
+  "package": "semgrep",
+  "upstream_version": "1.179.0",
+  "downstream_version": "1.179.0+specfact.1",
+  "mcp_from": "1.29.0",
+  "mcp_to": "1.30.0",
+  "python_versions": [
+    "3.11",
+    "3.12",
+    "3.13"
+  ],
+  "build_runtime_policy": {
+    "implementation": "CPython",
+    "python_versions": [
+      "3.11",
+      "3.12",
+      "3.13"
+    ],
+    "wheel_compression": "ZIP_STORED",
+    "description": "Runtime-policy digest; actual executable and environment identities are bound separately by each cell report."
+  },
+  "build_runtime_digest": "31432b8918f5a5aef72fbdb8f5aefe74090f5002917c33e7f4f78478998c0f51",
+  "wheels": [
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-macosx_10_14_x86_64.whl",
+      "platform_tag": "macosx_10_14_x86_64",
+      "upstream_sha256": "34b5e801e3f4325c93014124ccfab6da96857f74aae68458d2a07defd4727b0f",
+      "upstream_url": "https://files.pythonhosted.org/packages/85/4b/4cbaa0c3c124ae7d522e688c01f06013038ff59cc818c21dfa44c96380b3/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-macosx_10_14_x86_64.whl",
+      "runner": "macos-15-intel",
+      "containers": {}
+    },
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-macosx_11_0_arm64.whl",
+      "platform_tag": "macosx_11_0_arm64",
+      "upstream_sha256": "9b57026f587a4bc7833bca2b6e4d6778072a79dcf0b9f2e5e01d3d5df39c7759",
+      "upstream_url": "https://files.pythonhosted.org/packages/bd/77/b573a0faa5a5b0848dc884a0f8595fcb5c550f55fa5f455a233b29a52c0c/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-macosx_11_0_arm64.whl",
+      "runner": "macos-15",
+      "containers": {}
+    },
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-manylinux_2_34_x86_64.whl",
+      "platform_tag": "manylinux_2_34_x86_64",
+      "upstream_sha256": "b529c4db63f293918989b84ce4640f12f1b1e4680d9e7fcab5f3554f9113dfc5",
+      "upstream_url": "https://files.pythonhosted.org/packages/cc/6c/621944b4843c7484aeaefd5b232d93780bdf95259567c10a9a8129f08dc6/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-manylinux_2_34_x86_64.whl",
+      "runner": "ubuntu-24.04",
+      "containers": {}
+    },
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-manylinux_2_34_aarch64.whl",
+      "platform_tag": "manylinux_2_34_aarch64",
+      "upstream_sha256": "c23d79c4839540372acc39b59aad167c1c7f3dc21bacacb27f19aa2edd79d271",
+      "upstream_url": "https://files.pythonhosted.org/packages/e3/ba/b9f1afbed852a21b6f7e72c064343161c5ab249954c46db1796b59314290/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-manylinux_2_34_aarch64.whl",
+      "runner": "ubuntu-24.04-arm",
+      "containers": {}
+    },
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-musllinux_1_2_x86_64.whl",
+      "platform_tag": "musllinux_1_2_x86_64",
+      "upstream_sha256": "69bce348296374df6c51e72758801ce06dd18d6dfb307bc73d24b9de53bbe5f1",
+      "upstream_url": "https://files.pythonhosted.org/packages/ee/c1/59096c02408630b79be19c5b97d145786141e254782ab0e62939c1eea52d/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-musllinux_1_2_x86_64.whl",
+      "runner": "ubuntu-24.04",
+      "containers": {
+        "3.11": "python:3.11-alpine3.22@sha256:a4fc589b32e824f3f02ed9d7e7be19518aa47e105b80416336af9f202275a489",
+        "3.12": "python:3.12-alpine3.22@sha256:a190708a2dec1bd18b1decb539f8e8f5407abaa9bf39cacda583f7f8c11db322",
+        "3.13": "python:3.13-alpine3.22@sha256:e81548ac35b07a3bd4805f275107592ef458b1e893c0e04d45aedaa19416cca5"
+      }
+    },
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-musllinux_1_2_aarch64.whl",
+      "platform_tag": "musllinux_1_2_aarch64",
+      "upstream_sha256": "dc6317fbfad49b1dbe396df7da7d9702cffc5ea9ea62cb3b4b2209824496b425",
+      "upstream_url": "https://files.pythonhosted.org/packages/1d/41/dc51c4e2f2cd730c1512739db792f70f7e9c665f6a0fb40fef62ff4b8eb3/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-musllinux_1_2_aarch64.whl",
+      "runner": "ubuntu-24.04-arm",
+      "containers": {
+        "3.11": "python:3.11-alpine3.22@sha256:a4fc589b32e824f3f02ed9d7e7be19518aa47e105b80416336af9f202275a489",
+        "3.12": "python:3.12-alpine3.22@sha256:a190708a2dec1bd18b1decb539f8e8f5407abaa9bf39cacda583f7f8c11db322",
+        "3.13": "python:3.13-alpine3.22@sha256:e81548ac35b07a3bd4805f275107592ef458b1e893c0e04d45aedaa19416cca5"
+      }
+    },
+    {
+      "filename": "semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-win_amd64.whl",
+      "platform_tag": "win_amd64",
+      "upstream_sha256": "6c6cf104ad0959c0b11de56d15c5d31f56949c620b4bd130c5d1fb899f2bb5a3",
+      "upstream_url": "https://files.pythonhosted.org/packages/ec/3e/dbf54b028afb807f26dc1e1c94489faac5926a8fa745b41bf505b4c53a7e/semgrep-1.179.0-cp310.cp311.cp312.cp313.cp314.py310.py311.py312.py313.py314-none-win_amd64.whl",
+      "runner": "windows-2022",
+      "containers": {}
+    }
+  ],
+  "uv_bootstrap": {
+    "version": "0.12.19",
+    "wheels": [
+      {
+        "filename": "uv-0.12.19-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.musllinux_1_1_aarch64.whl",
+        "sha256": "b466eb0f74645883df52446d54474905e8515d75fdf0b313bf099dedc3237896",
+        "url": "https://files.pythonhosted.org/packages/49/5c/4690490a19726b44d8fd01cdbdc56061fdebf99bb3e466215f276eefbd5d/uv-0.12.19-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.musllinux_1_1_aarch64.whl"
+      },
+      {
+        "filename": "uv-0.12.19-py3-none-musllinux_1_1_x86_64.whl",
+        "sha256": "a6512549e6bf12013190639bd5d9ef780f197d7adf4770a628c5e681577543d8",
+        "url": "https://files.pythonhosted.org/packages/28/cd/e57952eef1e24d52403a73c25c73d5697791eb72debe4a2facf9006fcba5/uv-0.12.19-py3-none-musllinux_1_1_x86_64.whl"
+      }
+    ]
+  }
+}
diff --git a/openspec/CHANGE_ORDER.md b/openspec/CHANGE_ORDER.md
@@ -4,6 +4,15 @@ This document is the **single source of truth for active work** in this
 repository. It lists what is in flight, what is paused, and the order in which
 active changes should be implemented.
 
+## Downstream Semgrep admission (#772, 2026-10-16)
+
+The owner authorized `downstream-semgrep-admission` as a separate implementation
+PR under #747. Build metadata-only downstream wheels with fixed MCP, execute the
+seven-platform / three-Python matrix, and require exact protected provenance
+before production adoption. Candidate tests do not authorize their own artifacts
+or replace the currently blocked frozen audit. Preserve every existing gate,
+provider pin and signature boundary. No merge or main promotion is authorized.
+
 ## Authorized #747 dependency stack (2026-10-10)
 
 The owner approved `dev <- #744 <- #727 <- #752 <- #754 <- #753`, retaining
@@ -73,7 +82,7 @@ Recovered from uncommitted proposal-only feature worktrees into local `dev`; rem
 
 | Bucket | Count | Location |
 |---|---:|---|
-| **Active-tree entries** | 41 | [`openspec/changes/`](changes/) |
+| **Active-tree entries** | 47 | [`openspec/changes/`](changes/) |
 | **Parking-lot entries** | 21 | [`openspec/parking-lot/`](parking-lot/) |
 | **Archived** | 120 | [`openspec/changes/archive/`](changes/archive/) |
 

diff --git a/openspec/changes/downstream-semgrep-admission/REVIEW_EXCEPTIONS.md b/openspec/changes/downstream-semgrep-admission/REVIEW_EXCEPTIONS.md
@@ -0,0 +1,47 @@
+# Preinstallation review exceptions
+
+The unchanged SpecFact review reports nine `MISSING_ICONTRACT` warnings and one
+`kiss.parameter-count.warning`. These are explicit, scoped exceptions under
+`docs/agent-rules/50-quality-gates-and-review.md`. The review scorer, thresholds,
+configuration and contract checker remain unchanged.
+
+## Standard-library preinstallation boundary
+
+The nine affected entry points are `build_candidate`, `verify_candidate`,
+`required_matrix`, `aggregate_candidate_reports`, `admit_artifact`,
+`CandidateWheel.candidate_audit_input`, `AdmittedWheel.audit_input`,
+`BoundAuditInput.assert_complete_result`, and the verification driver's `main`.
+
+These scripts run before an environment or a downstream artifact is trusted.
+Importing icontract or beartype here would require a third-party installation
+before the boundary can check it. A fallback decorator would falsely imply an
+enforced contract. Instead, the core validates its external JSON, paths,
+identities, archive members, signatures and audit inventory with explicit
+fail-closed checks. The driver validates its arguments and invokes the same
+boundary. The forty mapped regressions exercise observable success and rejection
+behavior. The independent final security review accepted this limited rationale.
+
+This exception applies only to these preinstallation entry points. It does not
+permit application APIs to omit contracts, or permit a caller to bypass admission.
+Reassess it if this code moves into an authenticated installed environment.
+
+## External MCP factory signature
+
+`_FixedManagerFactory.__call__` mirrors the MCP 1.30.0 factory arguments exactly.
+The reported six parameters include `self`. The regression checks the installed
+SDK signature before casting it to the protocol. Reducing the signature to five
+parameters would lose a tested control or misrepresent the external API. This
+exception applies only to that external protocol declaration.
+
+No other current review finding is covered by these exceptions. Real native
+platform proof and protected producer provenance remain separate obligations.
+
+## Credential fixture readability
+
+The FULL review also reports `ai-bloat.loc-vs-complexity` on the 53-line private
+`_authenticated_fixture`. Manual inspection retains that fixture. The same
+function defines ephemeral signed credentials, their signature verifier, and the
+server's audience policy. Splitting these single-use pieces into more helpers
+would spread the security assumptions across callers without removing logic.
+The HTTP test itself now contains only the ownership request sequence. This is
+an explicit retained readability advisory, not a change to the clean-code gate.