Bob Research Tools

bob_factcheck

Read-only

Checks one factual claim against the live web and returns {verdict, explanation, sources}, where verdict is supported, contradicted or unclear, usually in 4 to 9 seconds. Use it to verify a specific statement; use bob_research for open questions. Check one claim per call, phrased as a plain statement such as 'The Eiffel Tower is in Berlin'; split a compound claim into separate calls. Each call needs an x402 payment; if it cannot answer in time or the input is invalid, it fails and you are not charged.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`claim`	Yes	The factual claim to check, 1 to 500 characters, written as a statement.

Output Schema

TableJSON Schema

Name	Required	Description
`sources`	No	Source URLs behind the verdict.
`verdict`	Yes	How the live web treats the claim.
`explanation`	No	One or two sentences on why.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 3, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "additionalProperties": true,
+  "properties": {
+    "explanation": {
+      "description": "One or two sentences on why.",
+      "type": "string"
+    },
+    "sources": {
+      "description": "Source URLs behind the verdict.",
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "verdict": {
+      "description": "How the live web treats the claim.",
+      "enum": [
+        "supported",
+        "contradicted",
+        "unclear"
+      ],
+      "type": "string"
+    }
+  },
+  "required": [
+    "verdict"
+  ],
+  "type": "object"
+}

Changed1 schema field changedOct 3, 2026

addedInput schema / properties / claim / description

Added value: +"The factual claim to check, 1 to 500 characters, written as a statement."

First observedOct 3, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations cover the safety profile (readOnlyHint, openWorldHint, destructiveHint=false), yet the description adds non-obvious context beyond them: the x402 payment requirement per call, the 4-9 second latency, and the failure semantics ('if it cannot answer in time or the input is invalid, it fails and you are not charged'). This is exactly the kind of behavioral detail the annotations cannot convey.

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?

Purpose and output are front-loaded, and every sentence carries non-redundant information (payment, latency, failure handling, compound-claim splitting). Slightly dense but no filler; a small trim would be possible without losing substance.

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 an output schema present the description need not detail return values, and it doesn't over-explain them; combined with annotations covering safety and the description covering payment, timing, failure, and input constraints, an agent has everything needed to invoke this correctly.

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

Parameters4/5

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

Schema coverage is 100% and the single parameter is already documented as 1-500 characters written as a statement. The description nonetheless adds value with a concrete example and the 'one claim per call / split compound claims' rule, which guides correct input construction beyond the schema text.

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 ('Checks one factual claim against the live web'), names the output shape, and explicitly distinguishes itself from the sibling bob_research for open questions. An agent can route correctly 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?

Gives explicit when-to-use ('verify a specific statement') and the alternative ('use bob_research for open questions'), plus the constraint to check one claim per call and split compound claims. Nothing is left to inference.

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

All Bob Research Tools tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?