ClaimGate checks every claim in a draft against the evidence your organisation actually holds — the spec sheet, the case study, the paper. It enforces your prohibited-claims policy, and it flags the AI disclosure the law now requires. If a claim cannot be substantiated, the build fails.
Free: the starter kit — policy file, evidence folder, six-question checklist and a CI job. MIT source, no dependencies, Python 3.9+.
Claims requiring substantiation (14) ✗ [attribution] According to research at a leading university, 94% of teams… unsupported: the figure(s) 94% do not appear in any supplied evidence ✗ [statistic] …and we are fully ISO 27001 certified. contradicted: evidence states "…is not certified under ISO 27001" ~ [statistic] Meridian cut reconciliation from 22 hours to 9 hours partially_supported: the case study confirms both figures try: Meridian's finance team reduced reconciliation from 22 hours a week to 9 Policy findings (3) ✗ [prohibited] guaranteed absolute guarantees are unenforceable and treated as misleading advertising ✗ [disclosure] AI disclosure missing required under EU AI Act Article 50 and by platform labelling rules BLOCKED — 14 unsupported claim(s), 3 blocking policy finding(s). (exit 1)
The same check runs as an MCP server, so an agent can gate a draft before
it publishes instead of someone remembering to. Two entries are listed in
the official MCP Registry, and neither needs an account or anything
installed beyond uv:
io.github.caseone115/claimgate for the full engine, and
io.github.caseone115/claimgate-kit for the free starter kit,
which writes the policy, the evidence folder and the CI job into your
repository before it checks anything.
{
"mcpServers": {
"claimgate": {
"command": "uv",
"args": ["run", "--with", "mcp", "python", "server.py"]
}
}
}
The engine entry gives five tools: check_draft,
check_draft_json, list_claims,
check_policy_only and about. It fails closed the
same way the command line does —
with no evidence it answers “unverified”, never “fine”.
Source and setup.
The problem with AI-assisted copy is not that it reads badly. It is that a reader cannot tell a fabricated statistic from a real one — there is no signal in the prose that separates them. So it passes.
AI-generated articles removed for hallucinated content in a single quarter. Hallucination-driven takedowns are routine, not rare.
now require human review before AI creative publishes — but reviewing at AI volume is precisely what does not scale.
EU AI Act Article 50 transparency obligations applied. AI-generated content must be disclosed in defined circumstances.
They tell you a text was AI-written. Nobody was ever blocked from publishing over that. The question that decides whether an asset ships is whether this claim can be traced to something you can point at.
Most style guides already say this. Nothing checks it, so under deadline pressure it erodes. ClaimGate makes it mechanical, and makes the build fail when it is broken.
Every finding quotes the text it is about, says what is missing, and says what to do. A gate an editor cannot argue with is a gate they turn off — so nothing here is a black box.
Every checkable claim is extracted and adjudicated against your evidence. Any number in a claim must appear in the evidence — that check is a string search, not a judgement call, so a fabricated figure cannot be talked into a pass.
Your prohibited and restricted claims, written down once and enforced on every draft: guarantees, medical and financial claims, unsourced superlatives, named competitors, personal data.
A customer-facing AI-assisted asset with no AI disclosure is non-compliant however good the copy is. Checked as a property of the draft, not left to whoever uploads it.
unverified
— which blocks. It never fails towards "supported". The tests assert this,
because it is the one behaviour that makes the tool safe to trust.
Adjacent tools are useful and none of them do this.
| Question | Detectors | Governance suites | ClaimGate |
|---|---|---|---|
| Was this written by AI? | Yes | — | Not asked |
| Is every claim substantiated? | No | No | Yes |
| Enforces your banned-claim list? | No | Partly | Yes |
| Checks AI disclosure obligations? | No | Partly | Yes |
| Blocks the publish, in CI? | No | No | Exit code 1 |
| Can you read the rule that fired? | No | Rarely | Every finding quotes it |
The engine is MIT-licensed and public — read every line before you pay for anything. The starter kit is genuinely, permanently free.
List price $149. The launch price is $39 while the launch is running — no code needed on this link, and the list price is what it returns to.
Send the copy you are least confident about — reply to this email with the draft pasted in. You will get back a gate report naming every claim you cannot substantiate. Free, and no account required. If it finds nothing, you have lost nothing.