How do I install the Truthcheck skill?

Run npx skillmds add modbender/truthcheck in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Truthcheck safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: makes network calls. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Truthcheck?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Truthcheck free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Truthcheck?

modbender (@modbender) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Truthcheck by modbender — Agent Skill

Name: Truthcheck
Rating: 4.2 (5 reviews)
Author: modbender

Truthcheck

Verify claims, fact-check content, check URL trustworthiness, and trace claims to their origin using the TruthCheck CLI. Use when: (1) user asks to fact-check or verify a claim, (2) user wants to check if a URL/source is trustworthy, (3) user wants to trace where a claim originated, (4) user asks about misinformation or content verification. Requires: pip install truthcheck

modbender ebc7cd1 3.3 KB Updated Sep 9, 2026 12 repo stars

File contents

TruthCheck Skill

AI content verification CLI. Verify claims, check URLs, and trace misinformation.

Commands

Verify a claim

truthcheck verify "claim text" --llm gemini

Returns TruthScore 0-100 with breakdown (publisher, content, corroboration, fact-checks)
--llm is optional but improves accuracy
Add --json for structured output

Check URL trustworthiness

truthcheck check https://example.com
truthcheck check "text with multiple URLs"
truthcheck check -f file.txt

Detects hallucinated URLs that don't exist
Rates publisher credibility

Trace a claim to its origin

truthcheck trace "claim text"           # balanced, ~1-2 min
truthcheck trace "claim text" --quick   # fast, ~30 sec
truthcheck trace "claim text" --deep    # thorough, ~3-5 min

Finds original source and builds propagation tree

Look up a publisher

truthcheck lookup "publisher name"

Sync publisher database

truthcheck sync

Run periodically to keep publisher ratings current.

Interpreting TruthScore

Score	Label	Meaning
80-100	TRUE	Strong evidence supports the claim
60-79	POSSIBLY TRUE	Some supporting evidence, inconclusive
40-59	UNCERTAIN	Mixed or insufficient evidence
20-39	POSSIBLY FALSE	Evidence leans against the claim
0-19	FALSE	Strong evidence contradicts the claim

LLM Integration (Optional)

TruthCheck works without any LLM, but adding --llm improves content analysis accuracy.

truthcheck verify "some claim" --llm gemini    # recommended, fast & free tier
truthcheck verify "some claim" --llm openai    # GPT models
truthcheck verify "some claim" --llm anthropic # Claude models
truthcheck verify "some claim" --llm ollama    # local models, fully offline

Privacy: API keys are stored in your local environment only. TruthCheck never sends your keys to any external service — they are used solely for direct API calls to the respective LLM provider.

Environment Variables

Variable	When needed	Description
`GEMINI_API_KEY`	`--llm gemini`	Google AI API key (free tier available)
`OPENAI_API_KEY`	`--llm openai`	OpenAI API key
`ANTHROPIC_API_KEY`	`--llm anthropic`	Anthropic API key
`BRAVE_API_KEY`	`--search brave`	Brave Search API key

No keys needed for --llm ollama (runs locally) or default DuckDuckGo search.

Tips

Verify commands can take 15-60 seconds depending on search results
Without --llm: basic scoring using publisher reputation, corroboration, and fact-checks
With --llm: adds AI content analysis for better accuracy
--search brave gives better search results than default DuckDuckGo
For batch verification, loop through claims individually

---name: truthcheckdescription: Verify claims, fact-check content, check URL trustworthiness, and trace claims to their origin using the TruthCheck CLI. Use when: (1) user asks to fact-check or verify a claim, (2) user wants to check if a URL/source is trustworthy, (3) user wants to trace where a claim originated, (4) user asks about misinformation or content verification. Requires: pip install truthcheck--- # TruthCheck Skill AI content verification CLI. Verify claims, check URLs, and trace misinformation. ## Commands ### Verify a claim ```bash truthcheck verify "claim text" --llm gemini ``` - Returns TruthScore 0-100 with breakdown (publisher, content, corroboration, fact-checks) - `--llm` is optional but improves accuracy - Add `--json` for structured output ### Check URL trustworthiness ```bash truthcheck check https://example.com truthcheck check "text with multiple URLs" truthcheck check -f file.txt ``` - Detects hallucinated URLs that don't exist - Rates publisher credibility ### Trace a claim to its origin ```bash truthcheck trace "claim text" # balanced, ~1-2 min truthcheck trace "claim text" --quick # fast, ~30 sec truthcheck trace "claim text" --deep # thorough, ~3-5 min ``` - Finds original source and builds propagation tree ### Look up a publisher ```bash truthcheck lookup "publisher name" ``` ### Sync publisher database ```bash truthcheck sync ``` Run periodically to keep publisher ratings current. ## Interpreting TruthScore | Score | Label | Meaning | |-------|-------|---------| | 80-100 | TRUE | Strong evidence supports the claim | | 60-79 | POSSIBLY TRUE | Some supporting evidence, inconclusive | | 40-59 | UNCERTAIN | Mixed or insufficient evidence | | 20-39 | POSSIBLY FALSE | Evidence leans against the claim | | 0-19 | FALSE | Strong evidence contradicts the claim | ## LLM Integration (Optional) TruthCheck works without any LLM, but adding `--llm` improves content analysis accuracy. ```bash truthcheck verify "some claim" --llm gemini # recommended, fast & free tier truthcheck verify "some claim" --llm openai # GPT models truthcheck verify "some claim" --llm anthropic # Claude models truthcheck verify "some claim" --llm ollama # local models, fully offline ``` **Privacy:** API keys are stored in your local environment only. TruthCheck never sends your keys to any external service — they are used solely for direct API calls to the respective LLM provider. ## Environment Variables | Variable | When needed | Description | |----------|-------------|-------------| | `GEMINI_API_KEY` | `--llm gemini` | Google AI API key (free tier available) | | `OPENAI_API_KEY` | `--llm openai` | OpenAI API key | | `ANTHROPIC_API_KEY` | `--llm anthropic` | Anthropic API key | | `BRAVE_API_KEY` | `--search brave` | Brave Search API key | No keys needed for `--llm ollama` (runs locally) or default DuckDuckGo search. ## Tips - Verify commands can take 15-60 seconds depending on search results - Without `--llm`: basic scoring using publisher reputation, corroboration, and fact-checks - With `--llm`: adds AI content analysis for better accuracy - `--search brave` gives better search results than default DuckDuckGo - For batch verification, loop through claims individually

Frequently asked questions