Claim Grounding

by io.github.truepointmarketingpartners-dotcom

Deep verify

deep_verify

Read-onlyIdempotent

Use when a claim is high-stakes, or when check_answer or extract_claims marks it unsure (their next_step gives the exact request). Verifies up to three claims against Wikipedia, Wikidata, Google News, Europe PMC, FRED and SEC EDGAR; returns verdict, confidence, evidence for and against with URLs, and flags contradictions. Async: poll GET /v1/jobs/{job_id} free. $0.75 USDC on Base via x402. Read-only.

Input Schema

Name	Required	Description
`answer`	Yes	The claim or short text to verify (up to three claims are checked).
`sources`	No	Optional. Up to 10 sources of your own, used as extra evidence next to the public sources and cited with provider and source_type "caller". The response lists what was used in sources_used.
`sources_only`	No	Optional. true = judge the claim only against your sources (no public-source lookups). Needs a non-empty sources array.

Output Schema

Name	Required	Description
`tool`	Yes	Tool name.
`result`	No	Paid result: { mode: 'deep', status: 'queued', job_id, receipt }. Poll GET /v1/jobs/{job_id} for { verdict, confidence, contradiction, evidence_for[], evidence_against[], citations[] }.
`status`	Yes	payment_required: pay the HTTP route with x402 to get the result. ok: result is included.
`message`	Yes	Human-readable summary.
`payment`	No	Payment instructions. MCP tools/call does not charge or run the paid work; call the HTTP route with x402.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 13, 2026

addedInput schema / properties / sources

Added value: +{
+  "description": "Optional. Up to 10 sources of your own, used as extra evidence next to the public sources and cited with provider and source_type \"caller\". The response lists what was used in sources_used.",
+  "items": {
+    "additionalProperties": false,
+    "anyOf": [
+      {
+        "required": [
+          "url"
+        ]
+      },
+      {
+        "required": [
+          "text"
+        ]
+      }
+    ],
+    "description": "One source: {url} for a public https page we fetch, or {text, title?, url?} for text you already have.",
+    "properties": {
+      "text": {
+        "description": "Source text to check the claim against (up to 20,000 characters). When given, no fetch is made.",
+        "maxLength": 20000,
+        "minLength": 1,
+        "type": "string"
+      },
+      "title": {
+        "description": "Optional title shown in citations.",
+        "maxLength": 200,
+        "type": "string"
+      },
+      "url": {
+        "description": "Public https URL. Fetched with a 3.5 s timeout and a 512 KB cap; http, file and other schemes, private / loopback / link-local / metadata addresses, IP-literal hosts, custom ports and URLs with credentials are rejected (HTTP 400, not charged). With text, it is only the citation link.",
+        "format": "uri",
+        "maxLength": 2048,
+        "type": "string"
+      }
+    },
+    "type": "object"
+  },
+  "maxItems": 10,
+  "type": "array"
+}

addedInput schema / properties / sources_only

Added value: +{
+  "default": false,
+  "description": "Optional. true = judge the claim only against your sources (no public-source lookups). Needs a non-empty sources array.",
+  "type": "boolean"
+}

First observedOct 12, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover safety (readOnly, idempotent, openWorld), but the description adds genuinely non-inferable behavior: asynchronous execution with a free polling endpoint (GET /v1/jobs/{job_id}), a concrete price and payment rail ($0.75 USDC on Base via x402), and the full response shape (verdict, confidence, pro/con evidence with URLs, contradiction flags). These are traits no annotation or schema field conveys.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Five tight sentences, front-loaded with the usage trigger before capability, output, and cost details. Slight redundancy: 'Read-only' merely echoes readOnlyHint=true, and the pricing clause is wedged mid-paragraph, but overall density is high and waste is minimal.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With a rich output schema covering return values and annotations covering the safety profile, the description fills the remaining gaps an agent needs: when to select it over siblings, the async/polling flow, and the paid-invocation cost. Nothing required to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents `answer`, `sources`, and `sources_only` in detail, including URL/text tradeoffs and limits. The description only restates the 'up to three claims' cap and adds nothing about parameters beyond the schema, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource — 'Verifies up to three claims' — and enumerates the exact public sources consulted (Wikipedia, Wikidata, Google News, Europe PMC, FRED, SEC EDGAR). It also names sibling tools (check_answer, extract_claims) and the conditions that route to this one, so an agent can distinguish it without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit when-to-use: 'when a claim is high-stakes, or when check_answer or extract_claims marks it unsure (their next_step gives the exact request).' This names both trigger conditions and the upstream tools whose output drives the call, leaving nothing to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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