artifact: add PR body generator example

Adds a deterministic Markdown example artifact for the PR body generator, a generator script, and exact regeneration parity coverage.

Author: ProfRandom92

artifacts/pr_body_from_agent_bundle_example.md

@@ -0,0 +1,27 @@
+## Summary
+
+Deterministic agent artifact bundle evidence for this change.
+
+## Scope
+
+- `artifacts/agent_artifact_bundle_example.json`
+- `scripts/generate_agent_artifact_bundle_example.py`
+- `tests/test_agent_artifact_bundle.py`
+
+## Validation
+
+- `python -m compileall -q scripts/agent_artifact_bundle.py scripts/generate_agent_artifact_bundle_example.py`: `pass`
+- `pytest tests/test_agent_artifact_bundle.py -q`: `pass`
+
+## Safety Gate
+
+- result: `PASS`
+- ok: `true`
+- allow_dirty: `false`
+- problems: `none`
+
+## Evidence
+
+- branch: `feat/agent-artifact-bundle-example`
+- bundle_result: `PASS`
+- mcp_context_output_ref: `artifacts/mcp_context_layer_example.json`

scripts/generate_pr_body_from_agent_bundle_example.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+"""Generate a deterministic PR body Markdown example from an agent bundle."""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+if str(REPO_ROOT) not in sys.path:
+    sys.path.insert(0, str(REPO_ROOT))
+
+from scripts.pr_body_from_agent_bundle import render_pr_body_from_file
+
+INPUT_BUNDLE_PATH = REPO_ROOT / "artifacts" / "agent_artifact_bundle_example.json"
+OUTPUT_PATH = REPO_ROOT / "artifacts" / "pr_body_from_agent_bundle_example.md"
+
+
+def generate_pr_body_from_agent_bundle_example(output_path: Path = OUTPUT_PATH) -> Path:
+    rendered = render_pr_body_from_file(INPUT_BUNDLE_PATH)
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+    output_path.write_text(rendered, encoding="utf-8")
+    return output_path
+
+
+def main() -> int:
+    output_path = generate_pr_body_from_agent_bundle_example()
+    print(output_path.relative_to(REPO_ROOT).as_posix())
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

tests/test_pr_body_from_agent_bundle.py

@@ -4,8 +4,10 @@
 from pathlib import Path
 
 import scripts.pr_body_from_agent_bundle as pr_body
+from scripts.generate_pr_body_from_agent_bundle_example import generate_pr_body_from_agent_bundle_example
 
 ARTIFACT_PATH = Path("artifacts/agent_artifact_bundle_example.json")
+PR_BODY_ARTIFACT_PATH = Path("artifacts/pr_body_from_agent_bundle_example.md")
 
 
 def test_render_pr_body_from_committed_bundle_is_deterministic() -> None:
@@ -111,3 +113,10 @@ def test_cli_outputs_markdown_only_for_valid_bundle(tmp_path: Path, capsys) -> N
     assert captured.err == ""
     assert captured.out.startswith("## Summary\n")
     assert "## Safety Gate\n" in captured.out
+
+
+def test_pr_body_example_artifact_matches_generator_output(tmp_path: Path) -> None:
+    output_path = tmp_path / "pr_body_from_agent_bundle_example.md"
+    generate_pr_body_from_agent_bundle_example(output_path)
+
+    assert output_path.read_text(encoding="utf-8") == PR_BODY_ARTIFACT_PATH.read_text(encoding="utf-8")