Built from live public pages, OPIS's own methodology documentation, and a fresh robots.txt/agent-discovery probe this session. Every claim below cites its source and a re-runnable command.
No jargon. OPIS's price benchmarks are real, regulated, and load-bearing; the two fixes below just make the proof of that trustworthiness easier to find. Here is what each one is worth.
Your robots.txt singles out exactly the three IOSCO audit reports whose whole purpose is public trust-verification, keeping search engines and AI crawlers from indexing them; removing three lines lets the documents that prove your credibility be found by anyone checking it.
Every standard agent path 404s, so an AI researching carbon-price benchmarks has nothing structured to read; a simple manifest puts the world's reference for these prices in front of the tools increasingly used to look for it.
The OPIS Carbon Suite covers Ethanol RIN Credits (D6), Biodiesel RIN Credits (D4), Cellulosic Ethanol RIN Credits (D3), Advanced Biofuel RIN Credits (D5), California LCFS Carbon-Intensity and Carbon-Credit-Per-Gallon values, California Cap-and-Trade (CCA) allowances, CAR, plus a Global Carbon Market Report, Biodiversity Market Report, and Global Carbon Offsets Report. Its LCFS assessments are referenced directly as a CME Group futures settlement source ("California Low Carbon Fuel Standard (OPIS) Quotes"), meaning these prices are genuinely load-bearing in real derivatives markets, not just editorial content.
OPIS's public methodology page states: "OPIS complies with all international standards for price reporting agencies set forth by IOSCO," prioritizes "transaction data... as the bedrock of any price assessment" over bid/ask ranges, and links to a formal Complaints Policy and audit results. It publishes annual IOSCO PRA Principles audit reports as PDFs for 2022, 2023, and 2024, a real, ongoing compliance commitment, not a one-time claim.
OPIS's robots.txt is mostly a generic Yoast SEO block (crawl-delay 10, sitemap references), except for three specific, hand-added Disallow lines that block exactly the three IOSCO PRA Principles audit report PDFs (2022, 2023, 2024) named in finding 2 above. This is very likely an unintentional side-effect of a generic "don't index PDFs" or duplicate-content rule, not a deliberate transparency retreat, but it's worth naming plainly, because it directly touches the "verification" framing this review is built on: the one document set whose entire purpose is public trust-verification is the one OPIS's own robots.txt singles out by name to keep search engines (and by extension most AI crawlers) from indexing.
llms.txt, ai.txt, .well-known/agent-card.json, and openapi.json all return a TRUE HTTP 404 status on opis.com, confirmed consistently across repeated fetches, with minor (~0.6%) byte-size variance across requests consistent with WordPress's dynamic "related content" 404-page widget, not a soft-200 fake (the HTTP status itself is the reliable signal here, and it is consistently 404). Separately, and more materially: OPIS's actual benchmark methodology documents are public and unpaywalled, but the real daily numbers that matter, RIN prices, LCFS CI/CPG values, CCA allowance prices, sit entirely behind subscription products (RackPro, Context, and similar), with no free or agent-queryable API. A standard, defensible Bloomberg/Platts-style model for the industry, but the opposite of an open public good, worth stating plainly rather than assuming an AI agent could query live carbon prices from OPIS today.
