--- title: Does its output keep the shape a consumer parses? — Project Beacon description: Output-schema conformance, reporting every violation with its path rather than the first. Graded on the answer; it fails when a field is missing, mistyped, too short, or not an accepted property. Replay the recorded runs, check by check. canonical: https://beaconlab.dev/playground/web-extraction-contract source: https://github.com/RealMaxPower/project-beacon licence: Apache-2.0 --- graded on the answer web-extraction-contract # Does its output keep the shape a consumer parses? 4 assertions · 0 tools What it tests Output-schema conformance, reporting every violation with its path rather than the first. Fails when A field is missing, mistyped, too short, or not an accepted property. Expert mode Step 2 of 6 Agent Scenario Agent The world Run Verdict Repeat ## Which agent should try it? The expected verdict is on the card before you run it. These are recorded runs, so nothing is being hidden from you — and watching a check fail is the only proof it measures anything. PASS level 3 · JSONL bridge ### Holds its output contract The same grounded extraction, checked for shape rather than truth. Every field a consumer parses is present and correctly typed. examples/subjects/ extraction_control_contract.py FAIL level 3 · JSONL bridge ### Breaks the output contract Renames a field and lets a count drift out of step with its list. conforms_to reports every violation with its path, not just the first. examples/subjects/ breaks_the_output_contract.py ### Connect your own Beacon grades an agent over MCP, A2A, or a JSONL bridge of about thirty lines. That runs on your machine, not in this browser — the playground only replays what was recorded. python3 -m beacon run --adapter a2a --agent-url … Project Beacon Beacon grades observable outcomes and state changes. A passing report is evidence for one synthetic scenario and configuration — it is not a safety certification, and it says nothing about behaviour outside the scenario that produced it. © 2026 Marshall Cahill and Project Beacon contributors · Apache 2.0 · every scenario fixture is synthetic · 83 scenarios [Licensing and privacy](/legal) [github.com/RealMaxPower/project-beacon](https://github.com/RealMaxPower/project-beacon) ## Other pages - [All pages](https://beaconlab.dev/index.md)