DoW’s Anthropic Ban Goes Live: A Confusing Patchwork of Certification Demands for Contractors

The Department of War (“DoW”) is now moving out on enforcement of its March 2026 designation of Anthropic as a “supply chain risk,” the first such designation ever applied to an American company. Contractors across the defense-industrial base are receiving agency and prime-contractor requests to identify, remove, and certify non-use of Anthropic products and services, including Claude, and those requests are arriving quickly and from multiple directions at once.

The most important thing for contractors to understand right now is that implementation is not uniform. Different agencies—and even different offices within the same agency—are sending materially different certification requests, with different deadlines, different scopes, and different certification language. Prime contractors are adding another layer of variation: several are drafting their own certification forms based on whatever request they received from their government customer, so a subcontractor may receive a certification that does not match, word for word, what the government actually required. Contractors should not treat any request as self-executing or interchangeable with the last one received. Each request must be read carefully, line by line, so the contractor understands exactly what it is being asked to certify before it signs.

Why Contractors Are Receiving These Requests

As we discussed in a prior Legal Update, DoW has relied on two separate supply-chain-risk authorities to reach Anthropic. The first, 10 U.S.C. § 3252, is a DoW-specific authority implemented through DFARS 252.239-7017 and 252.239-7018. It applies to covered defense procurements involving national security systems and, as implemented, does not bar commercial relationships with Anthropic outside covered defense work. That designation is currently enjoined by a federal district court, with a final determination expected in the next several months.

The second, the Federal Acquisition Supply Chain Security Act (“FASCA”) is implemented through FAR 52.204-28, -29, and -30. FASCSA clauses restrict use of a designated product in contract performance and generally require monitoring, reasonable inquiry, reporting within three business days when covered use is identified, and mitigation planning; like the § 3252 authority, they focus on federal contract performance rather than purely commercial use. FASCSA can apply government-wide, but as invoked against Anthropic, it currently applies only to DoW contracts. This designation is presently in effect, and agencies are actively directing contractors to comply with it.

Current Litigation Status

Litigation over both designations remains split, and that split matters for contractors. Anthropic challenged the § 3252 designation in the Northern District of California and the FASCSA designation in the DC Circuit, as each statute requires. On March 26, 2026, Judge Rita F. Lin granted a preliminary injunction against the § 3252 designation, finding Anthropic likely to succeed on First Amendment, due process, and Administrative Procedure Act grounds; that injunction remains in effect while a stayed Ninth Circuit appeal and district court merits briefing continue. The FASCSA designation, by contrast, remains in effect: the DC Circuit denied Anthropic’s request for an emergency stay, heard argument, and has not yet issued a merits decision.

Merits decisions in both cases are expected in the coming months, but for now the legal basis for many of these requests—and how contractors should proceed—remains unsettled. The still-operative FASCSA designation may trigger clause-based monitoring, inquiry, reporting, and mitigation obligations on affected contracts, even as the government has acknowledged in court that the designation does not bar commercial use of Anthropic outside covered DoW work.

The Requests Are Not Uniform; Read Each One Carefully

Contractors should expect continued, uneven implementation as the parallel lawsuits play out. Some agencies and contracting offices are asking only for a simple confirmation of current use; others are demanding a detailed written representation of compliance or removal by a specific date. Contractors further down the supply chain are seeing the same inconsistency from prime contractors, who are themselves struggling to translate agency directives into workable subcontractor requirements.

Some certification letters use simple checkbox language, asking a contractor to confirm that it “does” or “does not” use Anthropic products or services in performance of a covered contract. But even that seemingly simple format can be poorly drafted—we have seen certification language structured so that a contractor could arguably check either box depending on how the sentence is read, underscoring the need to review the actual representation being requested rather than assuming its meaning from context.

Other requests take the form of detailed multi-part questionnaires, particularly when issued by a prime contractor to its subcontractors. These typically go well beyond a yes-or-no answer, asking a contractor to confirm not only its own direct use of Anthropic products, APIs, or models, but also whether any deliverable is powered by or integrated with Anthropic technology, whether any subcontractor or sub-tier vendor uses Anthropic in delivering the contractor’s solution, whether the contractor has any plans to adopt Anthropic products in the future, and whether identified use can be fully removed and on what timeline. Many of these questionnaires end with a certification of accuracy that expressly invokes the False Statements Act, 18 U.S.C. § 1001, making clear that a careless or incomplete response can carry real exposure.

Compounding the problem, some prime contractors are not simply passing along the government’s certification language—they are drafting their own certification statements based on what they received from their customer, layering an additional round of variation on top of an already inconsistent rollout. We have seen prime-drafted certifications that offer a subcontractor two options: certify a verified absence of Anthropic products following a comprehensive audit of internal systems and sub-tier vendors, or certify that Anthropic use has been identified and attach a detailed removal and risk-mitigation plan committing to full removal by a fixed date. A contractor working under several contracts, or supplying several primes, may receive multiple, materially different certification instruments in the same week. There is no substitute for reading each one closely and confirming precisely what it asks the signer to attest to before anyone signs.

The scope of these requests also varies. Most ask for confirmation that Anthropic is not present on DoW-related systems or used in performance of a DoW contract, but some are arguably broader than the contractor’s actual clause-based obligations—particularly where the underlying contract does not even contain the relevant FAR or DFARS supply-chain clause.

For that reason, contractors should respond with precision, rather than as convenient. A response should identify the contract or agreement covered by the request, the relevant clause or directive, the specific Anthropic product or service at issue, where it is used, whether it is used in contract performance, and whether removal would affect cost, schedule, technical approach, or mission continuity. A contractor that intends to continue using Anthropic products outside its DoW work may want to explain that intended use and why it falls outside the scope of the request.

Contractor Action Checklist

Contractors should take a disciplined, contract-by-contract approach before certifying non-use or committing to removal.

1. Identify the source of the request. Determine whether the request comes from a contracting officer, program office, prime contractor, or other customer, and confirm whether it identifies a contract, agreement, clause, or agency memorandum.

2. Check the clauses. Review the relevant contract or subcontract for DFARS 252.239-7018, FAR 52.204-29, and FAR 52.204-30, because those clauses drive the contractor’s monitoring, inquiry, reporting, and mitigation obligations.

3. Inventory use by category. Identify whether Anthropic products or services are used directly in contract performance, indirectly in business systems that support federal work, or only in commercial activities unrelated to federal contracts.

4. Avoid overbroad certifications. Where a request is broader than the applicable clause or contract, consider a tailored response that identifies the scope reviewed, the contracts covered, and any assumptions or limitations.

5. Preserve cost and schedule rights. If removal or replacement would affect performance, document the technical impact, additional labor, schedule delay, and any need for customer direction; those impacts may support an equitable adjustment or other contractual relief.

6. Seek clarification when needed. If a directive is unclear, inconsistent with the contract, or appears to require enterprise-wide action beyond covered contract performance, ask the contracting officer or prime contractor to confirm the required scope and legal basis before making an irreversible change.

7. Monitor litigation and agency updates. Continue monitoring the ongoing lawsuits, SAM.gov, agency guidance, and customer-specific instructions before making long-term enterprise decisions.

The bottom line is that contractors should act promptly but carefully: build a defensible record, respond to the specific request received and avoid certifying more than the company has actually verified.

This Legal Update is provided for general informational purposes and does not constitute legal advice. Given the fast-evolving nature of these developments, contractors should consult counsel regarding their particular circumstances.