Fact-check claims against live web sources: verbatim evidence, coherence-gated verdict.
Maintain this server? Claim it
Call this server's tools from your browser. Nothing to install.
Requests go through mcptry because browsers can't call most MCP servers directly. Header values are sent to the server for that request only and are never stored or logged.
Tool list from our last check. Connect live to refresh it.
PAID tool ($0.25 USDC via x402, Base). Fact-check a claim against live web sources: the claim is decomposed into sub-claims, sources are fetched live, Jev jurors judge per-source-family entailment with verbatim-quote evidence that must pass an anti-hallucination substring gate, and the verdict is coherence-gated (coherence = |sum(w*d)| / sum(w) over source families, weights 3/2/1 by source class) and sealed as a stored receipt. Send the x402 PAYMENT-SIGNATURE header on the /mcp request; without payment the call returns the canonical x402 challenge (HTTP 402, amount 250000 = $0.25 USDC, payTo of the canonical SML receiver). If the jury is not configured the call fails before any payment is requested, so nobody pays for a check that cannot run.
The claim to fact-check, as a single statement or a short paragraph.
Optional public HTTPS source URLs to check against (max 8). When omitted or fewer than 2 are usable, ClaimGate searches the live web.
Optional caller-provided decomposition of the claim into sub-claims (max 4). When omitted, the claim text is split into sentences.
This tool isn't marked read-only, so it may change something on the server or in an account you connected.
Pick your client. Values in capitals, like YOUR_TOKEN, are yours to fill in.
claude mcp add --transport http claimgate https://claimgate.onrender.com/mcp
PAID tool ($0.25 USDC via x402, Base). Fact-check a claim against live web sources: the claim is decomposed into sub-claims, sources are fetched live, Jev jurors judge per-source-family entailment with verbatim-quote evidence that must pass an anti-hallucination substring gate, and the verdict is coherence-gated (coherence = |sum(w*d)| / sum(w) over source families, weights 3/2/1 by source class) and sealed as a stored receipt. Send the x402 PAYMENT-SIGNATURE header on the /mcp request; without payment the call returns the canonical x402 challenge (HTTP 402, amount 250000 = $0.25 USDC, payTo of the canonical SML receiver). If the jury is not configured the call fails before any payment is requested, so nobody pays for a check that cannot run.
| Argument | Type | Description |
|---|---|---|
| claim* | string | The claim to fact-check, as a single statement or a short paragraph. |
| sources | array | Optional public HTTPS source URLs to check against (max 8). When omitted or fewer than 2 are usable, ClaimGate searches the live web. |
| sub_claims | array | Optional caller-provided decomposition of the claim into sub-claims (max 4). When omitted, the claim text is split into sentences. |
{
"type": "object",
"required": [
"claim"
],
"properties": {
"claim": {
"type": "string",
"maxLength": 2000,
"minLength": 10,
"description": "The claim to fact-check, as a single statement or a short paragraph."
},
"sources": {
"type": "array",
"items": {
"type": "string",
"maxLength": 2048
},
"maxItems": 8,
"description": "Optional public HTTPS source URLs to check against (max 8). When omitted or fewer than 2 are usable, ClaimGate searches the live web."
},
"sub_claims": {
"type": "array",
"items": {
"type": "string",
"maxLength": 2000,
"minLength": 8
},
"maxItems": 4,
"description": "Optional caller-provided decomposition of the claim into sub-claims (max 4). When omitted, the claim text is split into sentences."
}
},
"additionalProperties": false
}The full public ClaimGate methodology: coherence formula, source-class weights, verdict thresholds, the anti-hallucination verbatim-quote gate, family independence rules, and honest limits. calibrated:false — thresholds are stated, not fitted.
No arguments.
{
"type": "object",
"properties": {},
"additionalProperties": false
}Free preview: decompose a claim into sub-claims, fetch the sources live (or search for them), classify each source and group sources into independent families, and show exactly what a paid fact_check_claim would check. No verdict, no jury calls, no payment.
| Argument | Type | Description |
|---|---|---|
| claim* | string | The claim to fact-check, as a single statement or a short paragraph. |
| sources | array | Optional public HTTPS source URLs to check against (max 8). When omitted or fewer than 2 are usable, ClaimGate searches the live web. |
{
"type": "object",
"required": [
"claim"
],
"properties": {
"claim": {
"type": "string",
"maxLength": 2000,
"minLength": 10,
"description": "The claim to fact-check, as a single statement or a short paragraph."
},
"sources": {
"type": "array",
"items": {
"type": "string",
"maxLength": 2048
},
"maxItems": 8,
"description": "Optional public HTTPS source URLs to check against (max 8). When omitted or fewer than 2 are usable, ClaimGate searches the live web."
}
},
"additionalProperties": false
}Fetch a stored ClaimGate receipt by receipt_id (the sealed record of a paid fact check: sub-claims, sources, per-family verdicts with validated verbatim quotes, coherence, verdict, and payment).
| Argument | Type | Description |
|---|---|---|
| receipt_id* | string | Receipt id returned by fact_check_claim, e.g. cg_..._........ |
{
"type": "object",
"required": [
"receipt_id"
],
"properties": {
"receipt_id": {
"type": "string",
"maxLength": 128,
"minLength": 4,
"description": "Receipt id returned by fact_check_claim, e.g. cg_..._........"
}
},
"additionalProperties": false
}Check whether ClaimGate is live, whether the Jev jury is configured, which x402 facilitator is selected, how many receipts are stored, and the paid-check price.
No arguments.
{
"type": "object",
"properties": {},
"additionalProperties": false
}We read every tool's name, description and inputs the way the model will, looking for instructions hidden from you. A clean result means no warning signs, not a guarantee. Scanned Nov 1, 2026.