← All articles

Fact-Checker Agent: Verify Research Claims & Sources Locally

A fact-checker agent is a specialized AI that validates research claims, cross-checks web results, and surfaces contradictions between sources. With MyBenAI's on-device fact-checker agent, you can verify information locally without relying on any single LLM as your authoritative source.

The Problem With Trusting One AI

When you ask a language model a factual question, you're relying on its training knowledge and reasoning ability. But a single model—whether 1.7B or 70B parameters—can be wrong. It can hallucinate, conflate sources, or miss recent information. In research, trusting a single AI model is like trusting a single person's opinion: better than nothing, but risky.

What if you could ask multiple agents to examine the same sources independently? What if one agent retrieves sources, another agent questions their accuracy, and a third synthesizes what's true and what's suspect? That's the insight behind MyBenAI's multi-agent research approach, and the fact-checker agent is the critical piece that catches errors.

What Is a Fact-Checker Agent?

The fact-checker agent is a specialized component in MyBenAI's research system. Its job is simple: given a claim and a set of sources, check whether the sources actually support that claim. It doesn't ask "Is this true in the real world?" (that's unknowable from a phone). Instead, it asks "Do the sources we have say this?"

For example, suppose a researcher agent finds a source claiming "The Paris Agreement was signed in 2015" and another saying "The treaty was finalized in 2016." The fact-checker agent reads both sources, notes the discrepancy, and flags it: "Source A says 2015, Source B says 2016. These contradict. Human should verify." This keeps your research honest and highlights where sources disagree.

How the Research Workflow Works

MyBenAI's multi-agent research follows a clear workflow. You kick off a research request—for instance, "Verify claims about AI safety regulations across countries." Behind the scenes:

  1. Researcher agent: Searches for sources (via optional web search or your local documents), retrieves relevant pages or papers, and identifies key claims to verify.
  2. Fact-checker agent: Takes each claim and cross-checks it against the sources. It notes agreements, contradictions, and unsupported claims.
  3. Summarizer agent: Synthesizes the fact-checker's findings into a coherent summary, highlighting what is well-supported, what is contested, and where you need caution.

This is different from a single pass. With sub-agents working in parallel, the researcher and fact-checker can run simultaneously on different aspects, then converge on a final report.

Catching Contradictions

Fact-checking's primary strength is catching contradictions. When sources disagree on a fact, the agent flags it clearly. For example:

  • Source A claims "Company X was founded in 2010"; Source B claims "Company X was founded in 2011."
  • The fact-checker reports: "Contradiction detected. Source 1 says 2010 (URL: ...), Source 2 says 2011 (URL: ...). Verify which is correct."

You, the human, then decide: look up the company website, check the incorporation filing, or note that both dates might refer to different events (founding vs. public launch). The agent doesn't pretend to know; it highlights the disagreement and hands it back to you.

Querying Sources for Support

Beyond simple contradictions, the fact-checker agent can query: "Does this source actually support this claim?" A source might be tangentially related but not directly confirm a claim. The agent identifies when:

  • A claim appears in a source, but only as speculation or reported speech, not as fact.
  • A source discusses a related topic but doesn't explicitly state the claim.
  • A claim is inferred but not directly stated in the source.

This is where function calling and tool use matter. The fact-checker can call a "quote-source" tool to retrieve exact excerpts from documents and PDFs, not just summaries. This ensures verification is based on the actual text, not paraphrases.

Honest Limitations of On-Device Fact-Checking

On-device fact-checking has real constraints. A small model (1.7B–4B parameters) is weaker at reasoning than Claude or GPT-4. It may miss subtle inferences or overlook weak support for claims. It also can't access the live internet unless you've enabled optional web search with your own API key, and even then, it's checking cached results, not real-time facts.

Additionally, the fact-checker can only work with sources it has access to. If the relevant source is paywalled or offline, the agent can't check claims against it. And if all your sources agree on something false, the fact-checker won't catch it—it can only spot contradictions and unsupported claims within your collection.

Think of the fact-checker as a research assistant who flags inconsistencies, not an oracle. It augments your judgment; it doesn't replace it.

Multi-Agent Verification on Mobile

Running multiple agents in parallel on a phone requires careful resource management. MyBenAI's multi-agent system is battery-capped: the number of parallel agents scales based on whether your device is charging. On a full charge, you might run up to 4 agents in parallel. On battery, the system backs off to 2 or 1 agent, serializing fact-checking to preserve battery life. Each agent also has a 90-second timeout and a token budget, so no single query dominates inference time.

This means fact-checking is best-effort on a phone, not guaranteed to be exhaustive. For deep research with many sources, you might run the fact-checker overnight while plugged in, or export your sources to a desktop for more intensive verification.

Use Cases for On-Device Fact-Checking

Academic research: Verify claims across multiple papers or textbooks. Flag contradictions between sources so you can investigate further.

Journalism and reporting: Check quotes and facts from interviews or documents against each other. Catch when a source makes a claim unsupported by the evidence.

Legal review: Verify statements in contracts or agreements against referenced clauses. Flag inconsistencies.

Fact-checking personal claims: If someone makes a claim and provides sources, use the agent to verify whether the sources actually support the claim.

In all these cases, the agent doesn't declare truth; it highlights where sources conflict and where claims are unsupported.

Combining Fact-Checking With Research and Summarization

The fact-checker is most powerful as part of MyBenAI's full research assistant workflow with web search and citations. When you run a deep research request, the researcher finds sources, the fact-checker verifies them against each other, and the summarizer synthesizes the findings into a final report. This three-agent approach catches more errors than any single step alone.

Getting Started With Fact-Checking

To use the fact-checker agent in MyBenAI, start a research request with your question. The app will prompt you to choose agents: select "Fact-Checker" along with "Researcher" or "Summarizer." Give the agents 2–5 minutes to run (less if you're on low battery). The output will be a report showing:

  • Claims identified by the researcher agent.
  • Contradictions or unsupported claims flagged by the fact-checker.
  • A synthesis showing what is well-supported, contested, or unclear.

You review the report, investigate further if needed, and build your own conclusions. The agents work for you, not instead of you.

Trust Verification, Not Automation

The philosophy behind fact-checking agents is honest: automate the search for contradictions and gaps, but leave judgment to humans. A local, on-device fact-checker can't know absolute truth, but it can systematically highlight where your sources conflict. That's valuable. It transforms research from "ask one AI for answers" into "organize sources, find contradictions, and decide for yourself."

Ready to run verification on your research? Get MyBenAI and try the fact-checker agent. Explore how sub-agents orchestrate parallel research, dive into the full research workflow with citations and web search, or learn how the summarizer synthesizes contradictory sources into coherent insights.