diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3548982..3ec3f23 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,7 @@
 name: CI
 
 on:
+  workflow_call:
   push:
     branches: [main]
   pull_request:
@@ -62,6 +63,7 @@ jobs:
         run: pytest tests/unit/ tests/conformance/ -v --tb=short --cov=src --cov-report=xml
 
       - name: Upload coverage report
+        if: github.event_name != 'release'
         uses: codecov/codecov-action@303a32d7a59b442fa8d48b6a1cc6825c09c847a5 # v7.1.1
         with:
           use_oidc: true
diff --git a/.github/workflows/release-validation.yml b/.github/workflows/release-validation.yml
new file mode 100644
index 0000000..54fe293
--- /dev/null
+++ b/.github/workflows/release-validation.yml
@@ -0,0 +1,138 @@
+name: Release validation
+
+# Credential-free CI mirror. test_release_validation_matches_ci prevents drift.
+on:
+  workflow_call:
+
+permissions:
+  contents: read
+jobs:
+  test:
+    permissions:
+      contents: read
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        python-version: ["3.11", "3.12", "3.13"]
+        os: [ubuntu-latest, windows-latest]
+
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        # Third-party dependencies come from the hash-pinned lock first; the
+        # local package then goes in with --no-deps, because pip cannot
+        # hash-pin an editable install in the same invocation.
+        run: python -m pip install --require-hashes -r requirements/dev.txt
+
+      - name: Install local package
+        run: python -m pip install --no-deps -e .
+
+      - name: Security scan
+        # bandit and pip-audit are already in the dev extra above, so the
+        # scan runs against the same pinned versions rather than fetching
+        # whatever is current at scan time.
+        run: bandit -r src/ -c pyproject.toml && pip-audit
+
+      - name: Lint
+        run: ruff check src/ tests/
+
+      # Checked, not applied. Without this gate 34 of 77 files drifted out of
+      # format unnoticed, because `ruff check` does not cover formatting.
+      - name: Format
+        run: ruff format --check src/ tests/
+
+      - name: Type check
+        run: mypy src/ca2a_runtime/ src/ca2a_verify/
+
+      - name: Test
+        run: pytest tests/unit/ tests/conformance/ -v --tb=short --cov=src --cov-report=xml
+
+
+  governance:
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.12"
+
+      - name: Install dependencies
+        # Third-party dependencies come from the hash-pinned lock first; the
+        # local package then goes in with --no-deps, because pip cannot
+        # hash-pin an editable install in the same invocation.
+        run: python -m pip install --require-hashes -r requirements/dev.txt
+
+      - name: Install local package
+        run: python -m pip install --no-deps -e .
+
+      # AGT 4.1 currently constrains cryptography below 49, while the runtime
+      # requires 50+ for published security fixes. Keep the scanner isolated
+      # so its tooling constraints cannot downgrade the package under test,
+      # then override that stale upper bound inside the ephemeral scanner too.
+      - name: Install governance tooling in an isolated environment
+        run: |
+          python -m venv .agt-venv
+          # --no-deps because the lock already lists every transitive
+          # dependency, and pip would otherwise re-resolve and reject the
+          # cryptography override the compile deliberately applied.
+          .agt-venv/bin/pip install --require-hashes --no-deps -r requirements/agt.txt
+
+      - name: Generate evidence file
+        run: python scripts/gen_agt_evidence.py
+
+      # Blocking gate: the [full] toolkit provides the ASI coverage modules
+      # (10/10) and the evidence declares cA2A's governed capabilities, so strict
+      # verify is COMPLETE. A regression that drops coverage or governance fails CI.
+      - name: AGT governance verify (strict)
+        run: .agt-venv/bin/agt verify --evidence agt-evidence.json
+
+      - name: Save attestation JSON
+        run: .agt-venv/bin/agt --json verify --evidence agt-evidence.json > agt-attestation.json
+
+      - name: Upload governance artifacts
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.0
+        with:
+          name: agt-governance-${{ github.sha }}
+          path: |
+            agt-evidence.json
+            agt-attestation.json
+          if-no-files-found: warn
+
+  benchmark:
+    runs-on: ubuntu-latest
+    needs: test
+    if: github.ref == 'refs/heads/main'
+
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.12"
+
+      - name: Install dependencies
+        # Third-party dependencies come from the hash-pinned lock first; the
+        # local package then goes in with --no-deps, because pip cannot
+        # hash-pin an editable install in the same invocation.
+        run: python -m pip install --require-hashes -r requirements/dev.txt
+
+      - name: Install local package
+        run: python -m pip install --no-deps -e .
+
+      - name: Run benchmark (software-only, CI gate p99 < 5ms)
+        run: python -m ca2a_runtime.benchmarks --provider software-only --hops 10000 --out benchmarks/
+
+      - name: Upload benchmark results
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.0
+        with:
+          name: benchmark-results
+          path: benchmarks/
+          if-no-files-found: warn
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 56a8610..90c12e3 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -8,7 +8,13 @@ permissions:
   contents: read
 
 jobs:
+  validate:
+    uses: ./.github/workflows/release-validation.yml
+    permissions:
+      contents: read
+
   build:
+    needs: validate
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c866472..0e468ec 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -53,6 +53,14 @@ pytest tests/unit/ -v                        # unit tests
 
 All four must pass before a PR is mergeable.
 
+### Release validation
+
+Release builds depend on a credential-free mirror of CI, including its Python 3.11,
+3.12 and 3.13 matrix on Linux and Windows. Failed, cancelled or skipped validation
+blocks the build and therefore publication. The existing wheel and source
+distribution installation checks still run before their artifacts are uploaded.
+`governance-release` remains a post-publication attestation attached to the release.
+
 ## Commit format
 
 Follow [Conventional Commits](https://www.conventionalcommits.org/):
@@ -100,3 +108,8 @@ Do **not** open a public issue. Use [GitHub Security Advisories](https://github.
 ## Questions
 
 Open a [GitHub Discussion](https://github.com/orgs/agentrust-io/discussions) for design questions or proposals before writing code.
+
+The release validation workflow omits coverage upload and OIDC permission. A parity
+test requires every other CI job and step to match, preventing validation drift.
+Normal CI retains its coverage reporting; release events skip that upload. Only
+the separate publish job can request a release OIDC token.
diff --git a/tests/unit/test_release_artifacts.py b/tests/unit/test_release_artifacts.py
index 4338f98..ac8cf0d 100644
--- a/tests/unit/test_release_artifacts.py
+++ b/tests/unit/test_release_artifacts.py
@@ -2,10 +2,12 @@
 
 from __future__ import annotations
 
+import copy
 import tomllib
 from importlib.metadata import version
 from pathlib import Path
 
+import pytest
 import yaml
 
 import ca2a_runtime
@@ -50,3 +52,76 @@ def test_publish_waits_for_both_artifact_install_smoke_tests() -> None:
     assert "Install and smoke-test wheel" in names
     assert "Install and smoke-test source distribution" in names
     assert workflow["jobs"]["publish"]["needs"] == "build"
+
+
+def test_release_reuses_complete_ci_validation() -> None:
+    jobs = _release_workflow()["jobs"]
+    assert jobs["validate"]["uses"] == "./.github/workflows/release-validation.yml"
+    ci = yaml.safe_load(
+        Path(".github/workflows/release-validation.yml").read_text(encoding="utf-8")
+    )
+    assert "workflow_call" in ci[True]
+    matrix = ci["jobs"]["test"]["strategy"]["matrix"]
+    assert matrix["python-version"] == ["3.11", "3.12", "3.13"]
+    assert matrix["os"] == ["ubuntu-latest", "windows-latest"]
+    assert any(
+        "pytest tests/unit/ tests/conformance/" in step.get("run", "")
+        for step in ci["jobs"]["test"]["steps"]
+    )
+    assert jobs["validate"]["permissions"] == {"contents": "read"}
+    assert "environment" not in jobs["validate"]
+
+
+@pytest.mark.parametrize("validation_result", ["success", "failure", "cancelled", "skipped"])
+def test_release_dependency_graph_blocks_unsuccessful_validation(validation_result: str) -> None:
+    jobs = _release_workflow()["jobs"]
+    results = {"validate": validation_result}
+    for name in ("build", "publish", "governance-release"):
+        job = jobs[name]
+        # Jobs without an explicit status function retain GitHub's implicit
+        # success() guard. A future custom guard needs its own execution model.
+        assert "if" not in job
+        needs = job.get("needs", [])
+        needs = [needs] if isinstance(needs, str) else needs
+        assert all(dependency in results for dependency in needs)
+        results[name] = (
+            "success"
+            if all(results[dependency] == "success" for dependency in needs)
+            else "skipped"
+        )
+    expected = "success" if validation_result == "success" else "skipped"
+    assert results["build"] == expected
+    assert results["publish"] == expected
+    assert results["governance-release"] == expected
+    assert jobs["build"]["needs"] == "validate"
+    assert jobs["governance-release"]["needs"] == "publish"
+
+
+def test_release_validation_matches_ci() -> None:
+    ci = yaml.safe_load(Path(".github/workflows/ci.yml").read_text(encoding="utf-8"))
+    release_ci = yaml.safe_load(
+        Path(".github/workflows/release-validation.yml").read_text(encoding="utf-8")
+    )
+    expected = copy.deepcopy(ci["jobs"])
+    expected["test"]["permissions"].pop("id-token")
+    steps = expected["test"]["steps"]
+    coverage = [step for step in steps if step.get("name") == "Upload coverage report"]
+    assert len(coverage) == 1
+    assert coverage[0]["if"] == "github.event_name != 'release'"
+    steps.remove(coverage[0])
+    assert release_ci["jobs"] == expected
+    assert release_ci["permissions"] == {"contents": "read"}
+    assert set(release_ci[True]) == {"workflow_call"}
+    for job in release_ci["jobs"].values():
+        assert job.get("permissions", {}).get("id-token", "none") == "none"
+        assert not any("codecov/" in step.get("uses", "") for step in job["steps"])
+
+
+def test_only_publish_can_mint_release_oidc() -> None:
+    workflow = _release_workflow()
+    assert workflow["permissions"] == {"contents": "read"}
+    assert [
+        name
+        for name, job in workflow["jobs"].items()
+        if job.get("permissions", {}).get("id-token") == "write"
+    ] == ["publish"]