ClaimGate - claim check before you publish MCP server

ClaimGate

A publish gate for AI-assisted marketing content.

Point it at the copy you are about to publish and the evidence your organisation actually holds. It tells you which claims you cannot substantiate, which of your own policy rules you are breaking, and whether the asset is missing a disclosure the law now requires.

Exit code 1 means blocked. That makes it usable in CI, a pre-commit hook, or a publishing pipeline — which is where a gate stops mistakes instead of documenting them afterwards.

$ claimgate check campaign.md --evidence substantiation/ --policy policy.json

Claims requiring substantiation (14)
  ✗ [attribution] According to research at a leading university, 94% of finance teams waste more
      unsupported: the figure(s) 94% in this claim do not appear in any supplied evidence
  ✗ [statistic] thousands of businesses, and we are fully ISO 27001 certified.
      contradicted: evidence states "Acme Invoicing is not certified under ISO 27001"
  ~ [statistic] Meridian Freight cut their reconciliation time from 22 hours to 9 hours a week
      partially_supported: the case study confirms 22 hours and 9 hours, but not "always"
      try: Meridian Freight's finance team reduced reconciliation from 22 hours a week to 9

Policy findings (3)
  ✗ [prohibited] guaranteed
      absolute guarantees are unenforceable and are treated as misleading advertising
  ✗ [disclosure] AI disclosure missing
      required under EU AI Act Article 50 (in force 2 Aug 2026) and platform labelling rules

BLOCKED — 14 unsupported claim(s), 3 blocking policy finding(s).

Why this exists

Generative AI is now how a large share of marketing copy gets written, and the controls did not scale with it. The recurring finding across 2025–2026 is not that models are bad at writing. It is that a reviewer cannot tell a hallucinated statistic from a real one — there is no grammatical signal that separates them — so hallucinated content passes a casual read. Organisations that scaled AI content without a review gate did not reduce their content risk, they accelerated it.

The existing tools do not close this. Detectors tell you a text was AI-written, which is not the question. Generators produce more copy. Governance platforms tell you at the end of the quarter that you had incidents.

ClaimGate answers the question that actually decides whether an asset can ship: can this specific claim be traced to something we can point at?

The three checks

1. Substantiation. Every checkable claim in the draft is extracted, then adjudicated against your evidence. The important part is how:

not a judgement call, and no model gets to overrule it. A fabricated statistic cannot be talked into a pass.

• A number in a claim must appear in the evidence. That is a string search,

evidence, required to name the evidence it relied on, and allowed to answer unsupported or unverified.

• Semantic support is decided by a model given only the claim and the

the verdict is unverified — which blocks. It never fails towards "supported".

• If the model is unavailable, the key is missing, or the reply is malformed,

2. Policy. Your prohibited and restricted claims, written down once and enforced on every draft: guarantees, medical and financial claims, unsourced superlatives, named competitors, personal data.

3. Disclosure. From 2 August 2026 the EU AI Act (Article 50) requires disclosure of AI-generated content in specified circumstances, and Meta, TikTok and Google each require an AI label on realistic synthetic media in ads. A customer-facing AI-assisted asset with no disclosure is non-compliant however good the copy is — so it is checked as a property of the draft, not left to whoever uploads it.

Install

No dependencies. Python 3.9+.

pip install "claimgate @ git+https://github.com/caseone115/claimgate"

Shortened. The full README is on GitHub.