Fact Checking Python Packages

lenz-io

Official Python SDK + CLI for the Lenz fact-checking API — extract claims from AI output, assess or verify them, and get sourced verdicts with citations.

web-researcher-mcp

Give your AI assistant real web search, full-page reading, and multi-source research with citations that are never fabricated.

proofpath

Verify that the sources behind a claim actually say what the claim says — citation existence, retraction and entailment checks in one offline-first CLI.

jev-judge-mcp

Typed judgment tools for MCP agents. TypeSafe's Jev model as verify, screen, find, classify, rerank, decide, compare, extract, review, gate, and score: the model judges, policy decides auto, review, or escalate.

citevahti

Run unit tests on your manuscript. Check every manuscript claim against its cited evidence. Human-first, AI-second, Zotero-audited, local-first.

naragate-mcp

AI evidence engine that detects financial claims in Indonesian market narratives and verifies them against real financial data (Sectors v2).

sooth

Claim-by-claim fact-checking for AI output, designed for CI. PASS/FAIL/REVIEW with calibrated probabilities and source evidence.

openfactcheck

An Open-source Factuality Evaluation Demo for LLMs

halu

Python SDK for Komplex AI — a hallucination detector for LLM output. Score any response for hallucination risk in one call. Includes an MCP server.

corvee

A local, multi-agent-aware CLI task tracker and fact store for AI coding agents, with humans as a secondary user.

lastsearch

Reliable research infrastructure for AI agents. Evidence-backed web search with citations, confidence scores, and Clarity anti-hallucination. MCP server, REST API, Python SDK.

doubleblind-audit

Three layers that cannot see each other's mistakes: re-derive every number in prose from a file you committed, brief a reviewer that was told nothing, and audit the figure a reader will actually see. Works with Claude Code, Codex, DeepSeek, Kimi.

citefact

Do your sources actually say what you claim? Audits a manuscript against the full text of its cited sources: citations exist, quotes verbatim, claims supported.

footnote-mcp

Web research MCP server with claim verification — 45 tools for Claude Desktop and Cursor

aurelius-mcp

A fact-checked research MCP server — screen a topic, draft it, and verify every citation and claim against live web sources. Works in Claude, Gemini CLI, Cursor, and any MCP app.

argus-debate-ai

Debate-native multi-agent AI framework that eliminates LLM hallucination, overconfidence, and opacity. Structures knowledge evaluation as adversarial multi-round debates over a Conceptual Debate Graph (C-DAG) with Bayesian aggregation, CRUX protocol, 8 novel Evolution extensions, 27+ LLM providers, 50+ tools, and W3C-compliant provenance tracking.

researchzosho

Open-source deep research assistant with citations and memory. Ask a question and it searches the web, papers, old newspapers, archives and GitHub, writes a report, checks its citations against the sources, and keeps what it found. Use it for a literature review or your family tree. It runs with a local LLM (Ollama, llama.cpp) or a hosted API.

nikasha

Proof, not prose. Fact-check vulnerability reports against the real code at the exact version they name: an evidence dossier and sandboxed reproduction for incoming reports.

llm-sidecar

Local sidecar that gives every tool on your machine grounded, cited, routed AI — no API key required. Library + OpenAI-compatible daemon + MCP server + dashboard.

semviqa

[ACL 2026] SemViQA: A Semantic Question Answering System for Vietnamese Information Fact-Checking

onus

A claim checker: verifies a document's claims against its evidence, numbers deterministically

numaudit

Check that every number written in a document appears in the data it came from

touchneedle

Verify that the citations in a document are real, accurately described and consistently used — catches fabricated and hallucinated references in Markdown or .docx

langchain-graciousquotes

LangChain tools that check who really said a quote: verdict, source and citation from Gracious Quotes' fact-checked records.