diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 5508299..f1ed07b 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -7,6 +7,27 @@ updates:
     schedule:
       interval: "weekly"
     open-pull-requests-limit: 10
+    groups:
+      pydantic-runtime:
+        applies-to: "version-updates"
+        patterns:
+          - "pydantic"
+          - "pydantic-core"
+      httpx2-runtime:
+        applies-to: "version-updates"
+        patterns:
+          - "httpx2"
+          - "httpcore2"
+      pydantic-runtime-security:
+        applies-to: "security-updates"
+        patterns:
+          - "pydantic"
+          - "pydantic-core"
+      httpx2-runtime-security:
+        applies-to: "security-updates"
+        patterns:
+          - "httpx2"
+          - "httpcore2"
   - package-ecosystem: "docker"
     directory: "/services/account_unification"
     schedule:
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 655ff06..69a49a4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,6 +32,36 @@ jobs:
           prune-cache: true
       - name: Install locked dependencies
         run: uv sync --locked --extra dev
+      - name: Verify uv lock dependency metadata
+        run: uv pip check
+      - name: Verify exported hash lock
+        run: |
+          exported_requirements="${RUNNER_TEMP}/keyverse-requirements-dev.txt"
+          tracked_requirements_body="${RUNNER_TEMP}/keyverse-tracked-requirements-body.txt"
+          exported_requirements_body="${RUNNER_TEMP}/keyverse-exported-requirements-body.txt"
+          uv export \
+            --locked \
+            --format requirements.txt \
+            --extra dev \
+            --no-emit-project \
+            --output-file "${exported_requirements}"
+
+          # uv records the chosen output path in its two-line generated-file
+          # header. Compare the package graph and hashes while ignoring only
+          # that environment-specific provenance text.
+          tail -n +3 requirements-dev.txt > "${tracked_requirements_body}"
+          tail -n +3 "${exported_requirements}" > "${exported_requirements_body}"
+          cmp --silent "${tracked_requirements_body}" "${exported_requirements_body}" || {
+            diff --unified "${tracked_requirements_body}" "${exported_requirements_body}"
+            exit 1
+          }
+
+          export_lock_venv="${RUNNER_TEMP}/keyverse-export-lock"
+          uv venv "${export_lock_venv}"
+          VIRTUAL_ENV="${export_lock_venv}" uv pip install \
+            --require-hashes \
+            -r requirements-dev.txt
+          VIRTUAL_ENV="${export_lock_venv}" uv pip check
       - name: Lint
         run: uv run ruff check app tests tools
       - name: Docstrings
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4639f1a..e417773 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -73,6 +73,9 @@ Keep a Changelog, and releases use semantic versioning.
 - Added the product/technical gap baseline and its APA 7th doctoring record,
   including the current exact-head PR/Issue inventory and explicit
   `gap-not-claimed` runtime and release boundaries.
+- Exact-coupled `pydantic`/`pydantic-core` and `httpx2`/`httpcore2` updates are
+  grouped into atomic Dependabot pull requests, while CI independently installs
+  and checks both `uv.lock` and the exported hash-locked requirements graph.
 - Relying-party deployment controllers now send validated, secret-free metadata
   to Keyverse desired-state PUT instead of applying client representations
   directly to Keycloak; confidential credential placement remains a separate
diff --git a/docs/doctoring/dependabot-coupled-security-updates.md b/docs/doctoring/dependabot-coupled-security-updates.md
new file mode 100644
index 0000000..b734438
--- /dev/null
+++ b/docs/doctoring/dependabot-coupled-security-updates.md
@@ -0,0 +1,38 @@
+# Coupled Dependabot security updates — doctoring record
+
+## Status
+
+Active pull-request evidence only. This record describes the dependency-update contract on the contributor branch and does not claim protected `main` ships it until normal protected integration completes.
+
+## Problem
+
+Keyverse deliberately keeps `pydantic` with `pydantic-core` and `httpx2` with `httpcore2` in atomic Dependabot version-update pull requests because each parent/child pair is resolved together in the reviewed lock graph. The existing `groups` entries used `applies-to: version-updates`, so a Dependabot security update could still raise one member of a coupled pair independently. The dual-lock CI gate would then fail closed, but the security-update path would create a preventable blocked pull request rather than proposing one coherent graph.
+
+## Decision
+
+Define a separately named security-update group for each exact-coupled pair while retaining the existing version-update group. GitHub documents that one group rule cannot apply to both version and security updates; matching criteria must be represented as separately named groups with `applies-to: security-updates` for the security path.
+
+The executable regression requires all four groups and their exact package sets:
+
+- `pydantic-runtime` — version updates for `pydantic` and `pydantic-core`;
+- `httpx2-runtime` — version updates for `httpx2` and `httpcore2`;
+- `pydantic-runtime-security` — security updates for `pydantic` and `pydantic-core`; and
+- `httpx2-runtime-security` — security updates for `httpx2` and `httpcore2`.
+
+This changes Dependabot proposal grouping only. It does not weaken the existing `uv.lock` / exported hash-lock equivalence check, vulnerability scanning, review requirements, or protected-branch merge gates.
+
+## TDD traceability
+
+RED commit `f30c9b272af07e9592397d9e46d700493aeebe2b` expanded `test_exact_coupled_dependencies_update_atomically` to require the two security-update groups while the configuration still contained only the two version-update groups. GREEN commit `c593f8de3ca534bd58ee88d5f7b1bbbf15002d22` added the missing security-update groups without changing their package boundaries.
+
+Hosted exact-head CI remains the authoritative execution evidence. Queued, skipped, stale, predecessor-head, synthetic-only, author-only, or model-only evidence is not promoted to passing.
+
+## Rollback
+
+Rollback removes the two `*-security` group entries and this regression together. The operational consequence is not an unsafe merge: dual-lock CI remains fail-closed. Instead, Dependabot security updates for an exact-coupled parent/child pair may again arrive separately and become unnecessarily blocked.
+
+## References — APA 7th
+
+GitHub, Inc. (2026a). *Configuring Dependabot security updates*. GitHub Docs. Retrieved August 26, 2026, from https://docs.github.com/en/code-security/how-tos/secure-your-supply-chain/secure-your-dependencies/configure-security-updates
+
+GitHub, Inc. (2026b). *Dependabot errors*. GitHub Docs. Retrieved August 26, 2026, from https://docs.github.com/en/code-security/reference/supply-chain-security/troubleshoot-dependabot/dependabot-errors
diff --git a/services/account_unification/requirements-dev.txt b/services/account_unification/requirements-dev.txt
index e071985..4bb3135 100644
--- a/services/account_unification/requirements-dev.txt
+++ b/services/account_unification/requirements-dev.txt
@@ -1,5 +1,5 @@
 # This file was autogenerated by uv via the following command:
-#    uv export --format requirements.txt --extra dev --no-emit-project --output-file requirements-dev.txt
+#    uv export --locked --format requirements.txt --extra dev --no-emit-project --output-file requirements-dev.txt
 annotated-doc==0.0.5 \
     --hash=sha256:117bac03a25ede5df5440e855b32d556049ca169ead221505badf432fed4b101 \
     --hash=sha256:c7e58ce09192557605d8bbd92836d7e1d520ac9580096042c0bfd197efacf1bb
diff --git a/services/account_unification/tests/test_dependency_update_policy.py b/services/account_unification/tests/test_dependency_update_policy.py
new file mode 100644
index 0000000..b26063f
--- /dev/null
+++ b/services/account_unification/tests/test_dependency_update_policy.py
@@ -0,0 +1,112 @@
+"""Contracts for atomic dependency updates and dual-lock verification."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import yaml
+
+
+def _repository_root() -> Path:
+    """Return the Keyverse repository root from this test module."""
+    return Path(__file__).resolve().parents[3]
+
+
+def _dependabot_document() -> dict[str, object]:
+    """Parse and return the repository Dependabot configuration."""
+    document = yaml.safe_load(
+        (_repository_root() / ".github" / "dependabot.yml").read_text(
+            encoding="utf-8"
+        )
+    )
+    assert isinstance(document, dict)
+    return document
+
+
+def _pip_update() -> dict[str, object]:
+    """Return the account-unification pip update configuration."""
+    updates = _dependabot_document().get("updates")
+    assert isinstance(updates, list)
+
+    for update in updates:
+        if not isinstance(update, dict):
+            continue
+        if update.get("package-ecosystem") != "pip":
+            continue
+        if update.get("directory") != "/services/account_unification":
+            continue
+        return update
+    raise AssertionError("account-unification pip update configuration is missing")
+
+
+def _ci_source() -> str:
+    """Return the repository CI workflow source."""
+    return (
+        _repository_root() / ".github" / "workflows" / "ci.yml"
+    ).read_text(encoding="utf-8")
+
+
+def test_exact_coupled_dependencies_update_atomically() -> None:
+    """Packages with exact child pins stay atomic for version and security updates."""
+    groups = _pip_update().get("groups")
+    assert isinstance(groups, dict)
+
+    expected_groups = {
+        "pydantic-runtime": ("version-updates", {"pydantic", "pydantic-core"}),
+        "httpx2-runtime": ("version-updates", {"httpx2", "httpcore2"}),
+        "pydantic-runtime-security": (
+            "security-updates",
+            {"pydantic", "pydantic-core"},
+        ),
+        "httpx2-runtime-security": (
+            "security-updates",
+            {"httpx2", "httpcore2"},
+        ),
+    }
+    for group_name, (update_scope, expected_patterns) in expected_groups.items():
+        group = groups.get(group_name)
+        assert isinstance(group, dict)
+        assert group.get("applies-to") == update_scope
+        patterns = group.get("patterns")
+        assert isinstance(patterns, list)
+        assert set(patterns) == expected_patterns
+
+
+def test_ci_proves_both_lock_representations_are_equivalent() -> None:
+    """CI compares lock bodies before installing and checking both forms."""
+    workflow = _ci_source()
+
+    assert "uv sync --locked --extra dev" in workflow
+    assert "Verify uv lock dependency metadata" in workflow
+    assert "Verify exported hash lock" in workflow
+    assert workflow.count("uv pip check") == 2
+    assert "uv export" in workflow
+    assert "--format requirements.txt" in workflow
+    assert "--extra dev" in workflow
+    assert "--no-emit-project" in workflow
+    assert '--output-file "${exported_requirements}"' in workflow
+    assert (
+        'tracked_requirements_body="${RUNNER_TEMP}/keyverse-tracked-requirements-body.txt"'
+        in workflow
+    )
+    assert (
+        'exported_requirements_body="${RUNNER_TEMP}/keyverse-exported-requirements-body.txt"'
+        in workflow
+    )
+    assert 'tail -n +3 requirements-dev.txt > "${tracked_requirements_body}"' in workflow
+    assert (
+        'tail -n +3 "${exported_requirements}" > "${exported_requirements_body}"'
+        in workflow
+    )
+    assert (
+        'cmp --silent "${tracked_requirements_body}" "${exported_requirements_body}"'
+        in workflow
+    )
+    assert (
+        'diff --unified "${tracked_requirements_body}" "${exported_requirements_body}"'
+        in workflow
+    )
+    assert "--require-hashes" in workflow
+    assert "-r requirements-dev.txt" in workflow
+    assert 'VIRTUAL_ENV="${export_lock_venv}" uv pip install' in workflow
+    assert 'VIRTUAL_ENV="${export_lock_venv}" uv pip check' in workflow