WGA East hands writers an AI cloak, and its maker admits where it slips

One day before the Writers Guild of America East announced its new AI shield, the company that built it ran a last round of tests. On Monday 19 October, according to its own FAQ, Cloak's protected PDFs held up against the chat interfaces of Claude, Gemini and ChatGPT, and against the automatic summaries in Google Drive, Gmail and Adobe Acrobat. The same answer carries a sentence the trade coverage skipped: "However, our ChatGPT testing has shown varied effectiveness at the Extra High and Pro effort settings."

That sentence is the part worth reading twice. On Tuesday 20 October the guild, which has more than 7,500 members, said Cloak would be free to members as a member benefit, and that anyone else can add it to a WGAE Script Registration for $10. Variety, Deadline, The Hollywood Reporter, IndieWire and TheWrap all ran the news that afternoon, built from the same release. None of them reported testing the tool, and none of them named the people who made it.

What the guild is offering

The terms are simple. Members cloak their own files at no cost through wgaeast.org. Non-members pay $10 on top of a registration that costs them $25 and lasts 10 years, so a registered, cloaked script runs a non-member $35 in total. The guild says tens of thousands of writers and other creatives use its registry each year before sending work to agents, producers and actors, though it does not publish a figure.

The guild was clear about who it has in mind. Tom Fontana, its president, said members shouldn't have to worry that their work will train AI models after they send it to producers or agents, "or simply that the product of weeks, months, or years of work will be reduced to an AI-generated summary of an email attachment." The Hollywood Reporter put it more bluntly: the union doesn't want agency lit department assistants using AI for script coverage, or executives using it to skip reading a script before they give notes.

It fits the guild's recent record. In July it ended its 12-year partnership with Urbanworld, the BIPOC-focused film festival, after the festival added a programming lane for AI-generated films, and it runs an #AINeedsHumans campaign for members. Cloak moves that fight out of the contract and into the file itself.

How it works, by its maker's account

Cloak's public description is short. Its FAQ says AI systems read a PDF in one of two ways: they pull the embedded text directly, or they render the page and run optical character recognition (OCR) on the image. Cloak says it "embeds countermeasures in the document designed to resist both approaches." There is no white paper, no named method and no published patent application, though the guild and the company both call the software patent-pending.

The first half is a known class of trick. In June a Tulane paper on arXiv catalogued 25 ways a PDF's extracted text can differ from what the page shows a human, and found every commercial large language model (LLM) service it tested exposed to at least 12 of them. The authors found that exposure depends mostly on the ingestion stack, the software that turns a file into text for the model, which fits with Cloak naming chat interfaces rather than models. The second half, beating OCR on a page a person reads normally, is the hard part, and it is the part the ChatGPT caveat touches.

Cloak's stronger settings come with costs it states itself. Its "Deeper Protection" mode adds an extra invisible page to the page count, and its "Deepest Protection" mode works only in Preview, Apple's PDF viewer. A writer who wants the most protection has to know which software the reader will open the file in.

Who built it

None of the trade stories named the founders. Cloak was started by Rishi Ambavanekar and Tyler Sacharow, both University of Pennsylvania students in the class of 2029, and in May it won the $75,000 Perlman Grand Prize at Penn's Venture Lab Startup Challenge. Its pitch then was to publishers of news, novels and screenplays, offering "either full protection or opt-in monetization of training and inference," meaning a fee whenever a model is trained on or answers from the work. Its LinkedIn page lists two employees. The guild is the first named customer we could find.

Ambavanekar's line in the guild's release is about control. He said he built Cloak as "a way to give agency back to writers to protect against unwanted AI training, AI notes, and analysis." That is a fair description of what a consent tool can do, and a more careful one than the headlines that called it a block on AI.

What it means if you make films with AI

For writers, the math is easy. A free tool that makes a chatbot summary harder, and that marks your file with a clear no, is worth using. Treat it as friction rather than a lock: the maker ran its tests the day before launch, on consumer chat apps rather than the API pipelines (software that calls a model directly, with no chat window) or agents, and its own results already show a gap at the top end.

For AI filmmakers, the story runs the other way. Scripts are the raw input for breakdown, previs and storyboard tools. If cloaked PDFs spread through the guild's registry, more of the scripts that land on your desk may fail to parse, by design.

• If a writer sends you a cloaked script, ask for permission and a clean file before you run it through any tool, because working around the cloak is the exact behavior the guild built it to stop.
• If you are the writer, keep your clean original, cloak only the copy that goes out, and check which PDF reader your recipient uses before you pick the strongest setting.
• Never tell a collaborator that a cloaked file can't be read by AI, because the company that makes it does not claim that either.

Our take: Cloak is a useful consent signal sold as a shield. The guild did writers a favor by making it free, and the maker did everyone a favor by publishing its own caveat. The creators who respect that signal now are the ones writers will trust with a clean file later.

Timeline

• Date: 2023. Event: 148-day WGA strike; the 2023 MBA sets the first AI protections for film, TV and streaming writers; Source: WGAE release; Variety
• Date: 2025. Event: Cloak founded, per its LinkedIn company page; Source: LinkedIn
• Date: Wed 8 Apr 2026. Event: Co-founder Tyler Sacharow introduces Cloak to publishers on LinkedIn; Source: LinkedIn
• Date: Fri 1 May 2026. Event: Cloak wins the $75,000 Perlman Grand Prize at Penn's Venture Lab Startup Challenge (announced 5 May); Source: Wharton News; Penn Venture Lab
• Date: Fri 12 Jun 2026. Event: Tulane paper on PDF extraction gaps across commercial LLM services; Source: arXiv
• Date: Jul 2026. Event: WGAE ends its 12-year Urbanworld partnership over an AI film lane; Source: Variety
• Date: Mon 19 Oct 2026. Event: Date of Cloak's stated tests, including the ChatGPT caveat; Source: Cloak FAQ
• Date: Tue 20 Oct 2026. Event: WGAE announces the Cloak partnership; five trades publish the same afternoon; Source: WGAE release; Variety; THR; Deadline; IndieWire; TheWrap

Sources and what is unconfirmed: WGAE press release (20 Oct), read in full; Cloak FAQ, read 21 Oct; Wharton News and Penn Venture Lab (5 May); LinkedIn; The Hollywood Reporter and Variety (20 Oct); arXiv paper by Liu and Ming (12 Jun). Every effectiveness claim here is Cloak's own. We did not obtain or test a cloaked file, we found no patent application number, and we could not open the PDF compatibility guide the FAQ links to. The commercial terms between the guild and Cloak are not public. We found no statement from WGA West, which runs its own registry.