[codex] Add optional policy JSON output

tools/sbom-diff-and-risk/README.md

@@ -104,6 +104,7 @@ Offline `stale_package` evaluation is intentionally deferred. When enrichment is
 
 - `report.json`
 - `summary.json` when `--summary-json` is provided
+- `policy.json` when `--policy-json` is provided
 - `report.md`
 - `report.sarif`
 
@@ -183,6 +184,7 @@ sbom-diff-risk compare \
 - `--pyproject-group name`
 - `--out-json path`
 - `--summary-json path`
+- `--policy-json path`
 - `--out-md path`
 - `--out-sarif path`
 - `--policy path`
@@ -203,6 +205,12 @@ The checked-in [examples/sample-summary.json](examples/sample-summary.json) arti
 
 For CI dashboard, job-summary, and local-threshold examples, see [docs/summary-json-ci-cookbook.md](docs/summary-json-ci-cookbook.md).
 
+`--policy-json PATH` writes only policy-related JSON sections from the full
+report. It includes `policy_evaluation`, policy finding lists, `rule_catalog`,
+and `summary.policy` when policy evaluation is applied. For CI job-summary
+examples, see
+[docs/policy-decision-ci-cookbook.md](docs/policy-decision-ci-cookbook.md).
+
 ## Dependency Provenance Analysis (Opt-in)
 
 This section is about analyzing third-party package provenance signals. It is not about verifying the `sbom-diff-and-risk` tool's own release artifacts.

tools/sbom-diff-and-risk/docs/policy-decision-ci-cookbook.md

@@ -1,7 +1,8 @@
 # Policy decision CI cookbook
 
-This page shows how to consume policy decision explanation fields from
-`report.json` in CI without changing the `sbom-diff-risk` analysis model.
+This page shows how to consume policy decision explanation fields from the
+`--policy-json PATH` sidecar in CI without changing the `sbom-diff-risk`
+analysis model.
 
 Use this when a repository wants a small job summary that explains local policy
 blocks, warnings, or suppressions in machine-readable terms.
@@ -13,24 +14,25 @@ sbom-diff-risk compare \
   --before examples/cdx_before.json \
   --after examples/cdx_after.json \
   --policy examples/policy-strict.yml \
-  --out-json outputs/policy-report.json
+  --out-json outputs/report.json \
+  --policy-json outputs/policy.json
 ```
 
 The strict example policy can make the command return a policy failure exit
-code. In CI, keep the generated `outputs/policy-report.json` artifact so the
-policy decision metadata remains available for review.
+code. In CI, keep the generated `outputs/policy.json` artifact so the policy
+decision metadata remains available for review.
 
 ## Python consumer
 
-This example reads the full JSON report, prints compact policy status, and then
-prints the stable explanation fields for blocking and warning findings.
+This example reads the policy-only JSON sidecar, prints compact policy status,
+and then prints the stable explanation fields for blocking and warning findings.
 
 ```python
 import json
 from pathlib import Path
 
 report = json.loads(
-    Path("outputs/policy-report.json").read_text(encoding="utf-8")
+    Path("outputs/policy.json").read_text(encoding="utf-8")
 )
 
 policy = report.get("summary", {}).get("policy")
@@ -73,10 +75,10 @@ tool. The snippet does not create a new package safety verdict.
 ## PowerShell consumer
 
 This example uses `ConvertFrom-Json` to print the same policy status and
-explanation fields.
+explanation fields from the policy-only sidecar.
 
 ```powershell
-$report = Get-Content outputs/policy-report.json -Raw | ConvertFrom-Json
+$report = Get-Content outputs/policy.json -Raw | ConvertFrom-Json
 $policy = $report.summary.policy
 
 if ($null -eq $policy) {

tools/sbom-diff-and-risk/docs/report-schema.md

@@ -76,6 +76,18 @@ For reviewer-facing examples and interpretation guidance, see
 consumer snippets, see
 [policy-decision-ci-cookbook.md](policy-decision-ci-cookbook.md).
 
+The `--policy-json PATH` CLI option writes a policy-only JSON sidecar using the
+same policy-related sections from the full JSON report:
+
+- `policy_evaluation`
+- `blocking_findings`
+- `warning_findings`
+- `suppressed_findings`
+- `rule_catalog`
+- `summary.policy` when policy evaluation is applied
+- `provenance_policy` and `provenance_policy_impact` when provenance policy
+  fields are relevant
+
 ## Summary contract
 
 `summary` is the stable, compact entry point for automation that needs counts

tools/sbom-diff-and-risk/src/sbom_diff_risk/cli.py

@@ -13,7 +13,7 @@
 from .policy_evaluator import evaluate_policy
 from .policy_parser import build_policy
 from .presentation import effective_policy_evaluation, summarize_violations_by_rule
-from .report_json import render_report_json, render_summary_json
+from .report_json import render_policy_json, render_report_json, render_summary_json
 from .report_md import render_report_markdown
 from .report_sarif import render_report_sarif_output
 from .risk import evaluate_risks, summarize_risks
@@ -31,7 +31,10 @@ def build_parser() -> argparse.ArgumentParser:
         "compare",
         help="Compare two dependency inputs and write JSON and/or Markdown reports.",
         description="Compare two local dependency inputs and emit deterministic reports.",
-        epilog="Exit codes: 0 = success/no blocking violations, 1 = blocking policy violations, 2 = usage/parse/runtime error.",
+        epilog=(
+            "Exit codes: 0 = success/no blocking violations, "
+            "1 = blocking policy violations, 2 = usage/parse/runtime error."
+        ),
     )
     compare.add_argument("--before", type=Path, required=True, help="Path to the before input.")
     compare.add_argument("--after", type=Path, required=True, help="Path to the after input.")
@@ -59,7 +62,18 @@ def build_parser() -> argparse.ArgumentParser:
         help="Select a PEP 735 [dependency-groups] group when a compared input is pyproject.toml.",
     )
     compare.add_argument("--out-json", type=Path, default=None, help="Write a JSON report to this path.")
-    compare.add_argument("--summary-json", type=Path, default=None, help="Write the stable JSON summary object to this path.")
+    compare.add_argument(
+        "--summary-json",
+        type=Path,
+        default=None,
+        help="Write the stable JSON summary object to this path.",
+    )
+    compare.add_argument(
+        "--policy-json",
+        type=Path,
+        default=None,
+        help="Write policy evaluation and policy finding JSON sections to this path.",
+    )
     compare.add_argument("--out-md", type=Path, default=None, help="Write a Markdown report to this path.")
     compare.add_argument(
         "--out-sarif",
@@ -91,7 +105,10 @@ def build_parser() -> argparse.ArgumentParser:
     compare.add_argument(
         "--enrich-pypi",
         action="store_true",
-        help="Opt-in PyPI provenance and integrity enrichment. Default behavior remains offline with no network access.",
+        help=(
+            "Opt-in PyPI provenance and integrity enrichment. "
+            "Default behavior remains offline with no network access."
+        ),
     )
     compare.add_argument(
         "--pypi-timeout",
@@ -139,8 +156,17 @@ def run_compare(args: argparse.Namespace) -> int:
     scorecard_timeout = getattr(args, "scorecard_timeout", DEFAULT_SCORECARD_TIMEOUT_SECONDS)
 
     summary_json = getattr(args, "summary_json", None)
-    if args.out_json is None and summary_json is None and args.out_md is None and args.out_sarif is None:
-        raise ValueError("at least one of --out-json, --summary-json, --out-md, or --out-sarif must be provided")
+    policy_json = getattr(args, "policy_json", None)
+    if (
+        args.out_json is None
+        and summary_json is None
+        and policy_json is None
+        and args.out_md is None
+        and args.out_sarif is None
+    ):
+        raise ValueError(
+            "at least one of --out-json, --summary-json, --policy-json, --out-md, or --out-sarif must be provided"
+        )
     if pypi_timeout <= 0:
         raise ValueError("--pypi-timeout must be a positive number of seconds.")
     if scorecard_timeout <= 0:
@@ -232,6 +258,8 @@ def run_compare(args: argparse.Namespace) -> int:
         _write_text(args.out_json, render_report_json(report))
     if summary_json is not None:
         _write_text(summary_json, render_summary_json(report))
+    if policy_json is not None:
+        _write_text(policy_json, render_policy_json(report))
     if args.out_md is not None:
         _write_text(args.out_md, render_report_markdown(report))
     if args.out_sarif is not None:

tools/sbom-diff-and-risk/src/sbom_diff_risk/report_json.py

@@ -51,6 +51,27 @@ def render_summary_json(report: CompareReport) -> str:
     return json.dumps(_summary_to_dict(report), indent=2) + "\n"
 
 
+def render_policy_json(report: CompareReport) -> str:
+    policy_sections = build_policy_report_sections(report.metadata.policy_evaluation)
+    payload: dict[str, object] = {
+        "policy_evaluation": policy_sections["policy_evaluation"],
+        "blocking_findings": policy_sections["blocking_findings"],
+        "warning_findings": policy_sections["warning_findings"],
+        "suppressed_findings": policy_sections["suppressed_findings"],
+        "rule_catalog": policy_sections["rule_catalog"],
+    }
+
+    policy_summary = _policy_summary_to_dict(report.metadata.policy_evaluation)
+    if policy_summary is not None:
+        payload["summary"] = {"policy": policy_summary}
+
+    if policy_sections["provenance_policy"] is not None:
+        payload["provenance_policy"] = policy_sections["provenance_policy"]
+        payload["provenance_policy_impact"] = policy_sections["provenance_policy_impact"]
+
+    return json.dumps(payload, indent=2) + "\n"
+
+
 def _summary_to_dict(report: CompareReport) -> dict[str, object]:
     summary: dict[str, object] = {
         "added": report.summary.added,

tools/sbom-diff-and-risk/tests/test_cli_exit_codes.py

@@ -119,6 +119,7 @@ def test_cli_compare_help_mentions_policy_flags_and_exit_codes() -> None:
     assert result.returncode == 0
     assert "--out-sarif" in result.stdout
     assert "--summary-json" in result.stdout
+    assert "--policy-json" in result.stdout
     assert "--pyproject-group" in result.stdout
     assert "--policy" in result.stdout
     assert "--fail-on" in result.stdout

tools/sbom-diff-and-risk/tests/test_cli_policy_json.py

@@ -0,0 +1,142 @@
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from sbom_diff_risk import cli
+
+
+def test_cli_policy_json_writes_policy_only_file(tmp_path: Path) -> None:
+    project_root = Path(__file__).resolve().parents[1]
+    policy_path = tmp_path / "policy.json"
+
+    exit_code = cli.main(
+        [
+            "compare",
+            "--before",
+            str(project_root / "examples" / "cdx_before.json"),
+            "--after",
+            str(project_root / "examples" / "cdx_after.json"),
+            "--policy",
+            str(project_root / "examples" / "policy-strict.yml"),
+            "--policy-json",
+            str(policy_path),
+        ]
+    )
+
+    payload = json.loads(policy_path.read_text(encoding="utf-8"))
+
+    assert exit_code == 1
+    assert payload["summary"]["policy"] == {
+        "status": "fail",
+        "blocking": 3,
+        "warning": 1,
+        "suppressed": 0,
+    }
+    assert payload["policy_evaluation"]["applied"] is True
+    assert payload["policy_evaluation"]["exit_code"] == 1
+    assert len(payload["blocking_findings"]) == 3
+    assert len(payload["warning_findings"]) == 1
+    assert payload["blocking_findings"][0]["decision_reason"] == "added_package_count_exceeded_threshold"
+    assert payload["blocking_findings"][0]["policy_rule"] == "max_added_packages"
+    assert "components" not in payload
+    assert "risks" not in payload
+    assert policy_path.read_text(encoding="utf-8").endswith("\n")
+
+
+def test_cli_policy_json_matches_full_report_policy_sections(tmp_path: Path) -> None:
+    project_root = Path(__file__).resolve().parents[1]
+    report_path = tmp_path / "report.json"
+    policy_path = tmp_path / "policy.json"
+
+    exit_code = cli.main(
+        [
+            "compare",
+            "--before",
+            str(project_root / "examples" / "cdx_before.json"),
+            "--after",
+            str(project_root / "examples" / "cdx_after.json"),
+            "--policy",
+            str(project_root / "examples" / "policy-strict.yml"),
+            "--out-json",
+            str(report_path),
+            "--policy-json",
+            str(policy_path),
+        ]
+    )
+
+    report_payload = json.loads(report_path.read_text(encoding="utf-8"))
+    policy_payload = json.loads(policy_path.read_text(encoding="utf-8"))
+
+    assert exit_code == 1
+    assert policy_payload == _policy_sidecar_from_full_report(report_payload)
+
+
+def test_cli_policy_json_without_policy_records_not_applied(tmp_path: Path) -> None:
+    project_root = Path(__file__).resolve().parents[1]
+    policy_path = tmp_path / "policy.json"
+
+    exit_code = cli.main(
+        [
+            "compare",
+            "--before",
+            str(project_root / "examples" / "cdx_before.json"),
+            "--after",
+            str(project_root / "examples" / "cdx_after.json"),
+            "--policy-json",
+            str(policy_path),
+        ]
+    )
+
+    payload = json.loads(policy_path.read_text(encoding="utf-8"))
+
+    assert exit_code == 0
+    assert payload["policy_evaluation"]["applied"] is False
+    assert payload["policy_evaluation"]["exit_code"] == 0
+    assert "summary" not in payload
+    assert payload["blocking_findings"] == []
+    assert payload["warning_findings"] == []
+    assert payload["suppressed_findings"] == []
+
+
+def test_cli_policy_json_omitted_does_not_write_policy_file(tmp_path: Path) -> None:
+    project_root = Path(__file__).resolve().parents[1]
+    report_path = tmp_path / "report.json"
+    policy_path = tmp_path / "policy.json"
+
+    exit_code = cli.main(
+        [
+            "compare",
+            "--before",
+            str(project_root / "examples" / "cdx_before.json"),
+            "--after",
+            str(project_root / "examples" / "cdx_after.json"),
+            "--out-json",
+            str(report_path),
+        ]
+    )
+
+    assert exit_code == 0
+    assert report_path.is_file()
+    assert not policy_path.exists()
+
+
+def _policy_sidecar_from_full_report(report_payload: dict[str, object]) -> dict[str, object]:
+    policy_payload = {
+        "policy_evaluation": report_payload["policy_evaluation"],
+        "blocking_findings": report_payload["blocking_findings"],
+        "warning_findings": report_payload["warning_findings"],
+        "suppressed_findings": report_payload["suppressed_findings"],
+        "rule_catalog": report_payload["rule_catalog"],
+    }
+
+    summary = report_payload["summary"]
+    assert isinstance(summary, dict)
+    if "policy" in summary:
+        policy_payload["summary"] = {"policy": summary["policy"]}
+
+    if "provenance_policy" in report_payload:
+        policy_payload["provenance_policy"] = report_payload["provenance_policy"]
+        policy_payload["provenance_policy_impact"] = report_payload["provenance_policy_impact"]
+
+    return policy_payload