{
  "checker": {
    "claims": [
      {
        "claim": "A failed diff run returns exit code 2.",
        "command": "/tmp/caddiff-venv/bin/caddiff diff /tmp/no-old.stp /tmp/no-new.stp -o /tmp/caddiff-claim-out",
        "evidence": "/usr/bin/xvfb-run: 184: /tmp/caddiff-venv/bin/caddiff: not found",
        "expected": "exit code 2 and FreeCAD prerequisite error",
        "input": "missing STEP files",
        "kind": "claim",
        "outcome": "Real input did not produce the expected result: FreeCAD",
        "returncode": 127,
        "source": "`2` | the run failed (bad input, timeout, crash)",
        "source_checked": true,
        "source_file": "README.md",
        "verdict": "no"
      }
    ],
    "cycle_checks": [
      {
        "claim": "Scheduled or looping main behavior",
        "command": "",
        "evidence": "README and CLI entry points describe an on-demand diff command; no scheduler, loop, webhook, or cycle trigger is documented.",
        "expected": "identify the product trigger",
        "input": "source inspection",
        "kind": "cycle",
        "outcome": "README and CLI entry points describe an on-demand diff command; no scheduler, loop, webhook, or cycle trigger is documented.",
        "source": "repository entry points",
        "verdict": "yes"
      }
    ],
    "details": {
      "argv": [
        "/tmp/caddiff-venv/bin/caddiff",
        "diff",
        "examples/fixtures/moved_old.stp",
        "examples/fixtures/moved_new.stp",
        "-o",
        "/tmp/caddiff-replay",
        "--lang",
        "en"
      ],
      "blocker": "product invocation failed: {\"argv\": [\"/tmp/caddiff-venv/bin/caddiff\", \"diff\", \"examples/fixtures/moved_old.stp\", \"examples/fixtures/moved_new.stp\", \"-o\", \"/tmp/caddiff-replay\", \"--lang\", \"en\"], \"returncode\": 127, \"stdout\": \"/usr/bin/xvfb-run: 184: /tmp/caddiff-venv/bin/caddiff: not found\\n\", \"stderr\": \"\", \"needs_credentials\": false, \"needs_browser\": false}",
      "kind": "cli",
      "needs_browser": false,
      "needs_credentials": false,
      "returncode": 127,
      "stderr": "",
      "stdout": "/usr/bin/xvfb-run: 184: /tmp/caddiff-venv/bin/caddiff: not found",
      "working": false
    },
    "evidence_strength": "partly_checked",
    "example_checks": [
      {
        "claim": "Documented moved fixture diff",
        "command": "/tmp/caddiff-venv/bin/caddiff diff examples/fixtures/moved_old.stp examples/fixtures/moved_new.stp -o /tmp/caddiff-example-out --lang en",
        "deferred": false,
        "evidence": "/usr/bin/xvfb-run: 184: /tmp/caddiff-venv/bin/caddiff: not found",
        "expected": "diff manifest with two geometric differences",
        "input": "examples/fixtures/moved_old.stp examples/fixtures/moved_new.stp",
        "kind": "example",
        "outcome": "command exited with code 127",
        "returncode": 127,
        "source": "README.md, Benchmarks (measured, not estimated)",
        "verdict": "no"
      }
    ],
    "status": "FAIL"
  },
  "deviations": [
    "Pinned Git commit fetch failed: upload-pack: not our ref 09807c37471b93c946554bf855ba307ccc00a7ae",
    "System package install was blocked because Ubuntu 24.04 archive has no freecad candidate; PPA setup/install exceeded execution ceiling"
  ],
  "fault_owner": "prerequisite",
  "main_blocker": "FreeCAD cannot be installed from available Ubuntu package sources within the allowed setup run",
  "operation": "README fixture pair diff to generate the HTML, Markdown, image, and manifest report",
  "operation_scope": "Python 3.12 supported; FreeCAD and Xvfb required for local rendering",
  "outcome": "blocked",
  "plain_failure": "The diff command could not run because FreeCAD was unavailable.",
  "steps": [
    "Read README and example docs",
    "Python package install failed: externally-managed-environment; attempted venv setup",
    "Attempted documented Ubuntu FreeCAD install; freecad has no installation candidate",
    "Attempted adding FreeCAD PPA and installing freecad, xvfb, python3-venv; command exceeded 300 second ceiling"
  ],
  "stuck_step": "FreeCAD prerequisite installation",
  "suggested_fix": "Provide FreeCAD and Xvfb in the guest, then run the documented fixture diff."
}