Payload Check: data-quality filter for agents. Send any payload (tool/API output, scraped page, LLM answer, generated code, JSON, CSV) and get a 0-100 quality score, pass/warn/fail, tags and concrete issues: invalid or truncated JSON (with auto-repair), JSON Schema mismatches, syntax errors, bot-challenge/captcha/404 scrapes, LLM refusals, placeholders, repetition loops, mojibake. Deterministic, no LLM, payload not stored.